https://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&feed=atom&action=historyCoastal and marine sediments - Revision history2024-03-29T08:32:37ZRevision history for this page on the wikiMediaWiki 1.31.7https://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=80604&oldid=prevDronkers J at 15:33, 30 December 20232023-12-30T15:33:53Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 15:33, 30 December 2023</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>See also: [[Biogeomorphology of coastal systems]], [[Sandy shore habitat]], [[Meiofauna of Sandy Beaches]].</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>See also: [[Biogeomorphology of coastal systems]], [[Sandy shore habitat]], [[Meiofauna of Sandy Beaches]].</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>====Vertical segregation====</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>====Vertical segregation<ins class="diffchange diffchange-inline">, bed armoring</ins>====</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>A graded sediment bed stirred by an oscillatory current can undergo inverse grading by a process called 'kinematic vertical sorting'<del class="diffchange diffchange-inline"><ref>Legros, F. 2002. Can dispersive pressure cause inverse grading in grain flows? Journal of Sedimentary Research 72: 166– 170</ref>. This phenomenon has been observed, for example</del>, <del class="diffchange diffchange-inline">in the case of wave-induced </del>[[<del class="diffchange diffchange-inline">sheet flow</del>]]<del class="diffchange diffchange-inline"><ref>Hassan, W.N. and Ribberink, J.S. 2005. Transport processes of uniform and mixed sands in oscillatory sheet flow. Coastal Engineering 52: 745– 770</ref>. When a coarse sediment particle is lifted from its position in the soil matrix its place is readily filled by finer particles, preventing it from bouncing back</del>. <del class="diffchange diffchange-inline">The coarsest </del>sediments are <del class="diffchange diffchange-inline">therefore </del>lifted gradually to the surface leading to the formation of <del class="diffchange diffchange-inline">an </del>armor top layer <del class="diffchange diffchange-inline">covering </del>a sublayer of finer sediment. <del class="diffchange diffchange-inline">This armor layer inhibits suspension of the fine </del>sediments<del class="diffchange diffchange-inline">, whilst the coarser particles </del>are <del class="diffchange diffchange-inline">more exposed and set in motion more easily. The term 'inverse grading' points to the intuition that one would expect a layer of fine sediment at the surface rather than beneath it</del>.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>A graded sediment bed stirred by an oscillatory current can undergo inverse grading by a process called 'kinematic vertical sorting', <ins class="diffchange diffchange-inline">see </ins>[[<ins class="diffchange diffchange-inline">Seabed armoring</ins>]]. <ins class="diffchange diffchange-inline">Coarse </ins>sediments are lifted gradually to the <ins class="diffchange diffchange-inline">seabed </ins>surface<ins class="diffchange diffchange-inline">, </ins>leading to the formation of <ins class="diffchange diffchange-inline">a coarse </ins>armor top layer <ins class="diffchange diffchange-inline">that covers </ins>a sublayer of finer sediment. <ins class="diffchange diffchange-inline">These finer </ins>sediments are <ins class="diffchange diffchange-inline">therefore better protected from erosion</ins>.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>====Horizontal segregation====</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>====Horizontal segregation====</div></td></tr>
</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=80598&oldid=prevDronkers J at 10:07, 30 December 20232023-12-30T10:07:41Z<p></p>
<table class="diff diff-contentalign-left" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 10:07, 30 December 2023</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l188" >Line 188:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>See also: [[Biogeomorphology of coastal systems]], [[Sandy shore habitat]], [[Meiofauna of Sandy Beaches]].</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>See also: [[Biogeomorphology of coastal systems]], [[Sandy shore habitat]], [[Meiofauna of Sandy Beaches]].</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Spontaneous segregation of graded sediment can occur under certain conditions. This segregation generates contiguous patches of different types of sediment. The underlying feedback mechanism links sedimentation of fine material on a smooth muddy seabed to a locally reduced degree of turbulence <ref> Murray, A.B. and Thieler, E.R. 2004. A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and ‘rippled scour depressions’. Continental Shelf Res. 24: 295-315</ref>. As a result, fine material will mainly deposit in places where fine material already dominates on the seabed, so that these muddy patches increase in size and in mud content. This continues until no fine material is available any more from neighboring patches of coarser deposits from which the fines have been winnowed.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">====Vertical segregation====</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">A graded sediment bed stirred by an oscillatory current can undergo inverse grading by a process called 'kinematic vertical sorting'<ref>Legros, F. 2002. Can dispersive pressure cause inverse grading in grain flows? Journal of Sedimentary Research 72: 166– 170</ref>. This phenomenon has been observed, for example, in the case of wave-induced [[sheet flow]]<ref>Hassan, W.N. and Ribberink, J.S. 2005. Transport processes of uniform and mixed sands in oscillatory sheet flow. Coastal Engineering 52: 745– 770</ref>. When a coarse sediment particle is lifted from its position in the soil matrix its place is readily filled by finer particles, preventing it from bouncing back. The coarsest sediments are therefore lifted gradually to the surface leading to the formation of an armor top layer covering a sublayer of finer sediment. This armor layer inhibits suspension of the fine sediments, whilst the coarser particles are more exposed and set in motion more easily. The term 'inverse grading' points to the intuition that one would expect a layer of fine sediment at the surface rather than beneath it.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">====Horizontal segregation====</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Spontaneous <ins class="diffchange diffchange-inline">horizontal </ins>segregation of graded sediment can occur under certain conditions. This segregation generates contiguous patches of different types of sediment. The underlying feedback mechanism links sedimentation of fine material on a smooth muddy seabed to a locally reduced degree of turbulence <ref> Murray, A.B. and Thieler, E.R. 2004. A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and ‘rippled scour depressions’. Continental Shelf Res. 24: 295-315</ref>. As a result, fine material will mainly deposit in places where fine material already dominates on the seabed, so that these muddy patches increase in size and in mud content. This continues until no fine material is available any more from neighboring patches of coarser deposits from which the fines have been winnowed.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>      </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>      </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Bedforms===</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Bedforms===</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The bedforms described above do not occur with deposits of fine cohesive material (mud). Dewatering of freshly deposited mud is a slow process and mud layers therefore remain fluid for a long time as so-called [[Definitions of coastal terms#Mud|fluid mud]], see for example the article [[Dynamics of mud transport]]. Once consolidated, the erosion resistance is high, so that no bed ripples can form. Mud layers therefore have a smooth surface and exert little friction on the flow.  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The bedforms described above do not occur with deposits of fine cohesive material (mud). Dewatering of freshly deposited mud is a slow process and mud layers therefore remain fluid for a long time as so-called [[Definitions of coastal terms#Mud|fluid mud]], see for example the article [[Dynamics of mud transport]]. Once consolidated, the erosion resistance is high, so that no bed ripples can form. Mud layers therefore have a smooth surface and exert little friction on the flow.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>===<del class="diffchange diffchange-inline">Sediment </del>sorting===</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>===<ins class="diffchange diffchange-inline">Large-scale sediment </ins>sorting===</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Sediment sorting <del class="diffchange diffchange-inline">is </del>the spatial segregation of different types of sediment deposits. As indicated earlier, sediment deposition requires suitable hydrodynamic conditions, which depend on the type of sediment. Fine sediments cannot settle in high-energy environments (strong waves, strong currents). Temporary settling is possible when currents are weak (neap tide, slack tide) and in the absence of strong wave action. However, in situations where low-energy and high-energy conditions alternate, these temporary deposits will disappear. Although currents generally carry a mixture of different types of sediment, remaining deposits will only comprise grainsizes that cannot be resuspended under the most energetic conditions among the alternating conditions that occur at a specific location. Grain size analysis of sediment deposits therefore can provide an indication of the maximum hydrodynamic shear stresses that occur at a particular location<ref>Ward, S.L., Neill, S.P., Van Landeghem, K.J.J. and Scourse, J.D. 2015. Classifying seabed sediment type using simulated tidal-induced bed shear stress. Marine Geology 367: 94–104</ref><ref>Escobara, C.A., Mayerle, R. and Restrepo, D. 2019. Estimation of sediment grain sizes in a mesotidal area, Dithmarschen Bight,</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Sediment sorting<ins class="diffchange diffchange-inline">, </ins>the spatial segregation of different types of sediment deposits<ins class="diffchange diffchange-inline">, is a characteristic of mobile sediment beds</ins>. As indicated earlier, sediment deposition requires suitable hydrodynamic conditions, which depend on the type of sediment. Fine sediments cannot settle in high-energy environments (strong waves, strong currents). Temporary settling is possible when currents are weak (neap tide, slack tide) and in the absence of strong wave action. However, in situations where low-energy and high-energy conditions alternate, these temporary deposits will disappear. Although currents generally carry a mixture of different types of sediment, remaining deposits will only comprise grainsizes that cannot be resuspended under the most energetic conditions among the alternating conditions that occur at a specific location. Grain size analysis of sediment deposits therefore can provide an indication of the maximum hydrodynamic shear stresses that occur at a particular location<ref>Ward, S.L., Neill, S.P., Van Landeghem, K.J.J. and Scourse, J.D. 2015. Classifying seabed sediment type using simulated tidal-induced bed shear stress. Marine Geology 367: 94–104</ref><ref>Escobara, C.A., Mayerle, R. and Restrepo, D. 2019. Estimation of sediment grain sizes in a mesotidal area, Dithmarschen Bight, German North Sea. Marine Geology 417, 106006</ref>. A qualitative overview of the types of sediment deposits that form the seabed top layer under different hydrodynamic conditions is indicated in Table 3 for sandy coastal environments, together with the associated sediment transport modes and bedforms. These bedforms are themselves cause of sediment sorting. In low-energetic environments (weak currents, waves) the coarsest sediments accumulate in the troughs (swales) by preferential downward motion along the slip face of the bedforms<ref name=BN></ref>. In the case of stronger waves and currents the coarsest sediments are found at the bedform crest where fine sediments are most easily brought in suspension <ref>Van Oyen, T., Blondeaux, P. and Van den Eynde, D. 2013. Sediment sorting along tidal sand waves: A comparison between field observations and theoretical predictions. Continental Shelf Research 63: 23–33</ref>.  </div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>German North Sea. Marine Geology 417, 106006</ref>. A qualitative overview of the types of sediment deposits that form the seabed top layer under different hydrodynamic conditions is indicated in Table 3 for sandy coastal environments, together with the associated sediment transport modes and bedforms. These bedforms are themselves cause of sediment sorting. In low-energetic environments (weak currents, waves) the coarsest sediments accumulate in the troughs (swales) by preferential downward motion along the slip face of the bedforms<ref name=BN></ref>. In the case of stronger waves and currents the coarsest sediments are found at the bedform crest where fine sediments are most easily brought in suspension <ref>Van Oyen, T., Blondeaux, P. and Van den Eynde, D. 2013. Sediment sorting along tidal sand waves: A comparison between field observations and theoretical predictions. Continental Shelf Research 63: 23–33</ref>.  </div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l332" >Line 332:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Estuarine turbidity maximum]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Estuarine turbidity maximum]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Coastal mud belt]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Coastal mud belt]]</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>:[[Wave-induced soil liquefaction]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>:[[ Wave-induced soil liquefaction]]</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
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</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=80596&oldid=prevDronkers J at 22:18, 27 December 20232023-12-27T22:18:02Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 22:18, 27 December 2023</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l148" >Line 148:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* Quartz:  silicon dioxide crystal (SiO<sub>2</sub>);</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* Quartz:  silicon dioxide crystal (SiO<sub>2</sub>);</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://en.wikipedia.org/wiki/Mica Mica]: complex silicate minerals comprising elements K or Na and metal cations such as Al, Mg and Fe, that form crystals with a sheet-like arrangement of atoms;</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* [https://en.wikipedia.org/wiki/Mica Mica]: complex silicate minerals comprising elements K or Na and metal cations such as Al, Mg and Fe, that form crystals with a sheet-like arrangement of atoms;</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* Clay:  hydrous silicates that contain metal cations, generally aluminum. Most common clay minerals are [https://en.wikipedia.org/wiki/Kaolinite kaolinite]  (Al<sub>2</sub>Si<sub>2</sub>O<sub>5</sub>(OH)<sub>4</sub>), [https://en.wikipedia.org/wiki/Illite illite], [https://en.wikipedia.org/wiki/Smectite smectite] (incl. [https://en.wikipedia.org/wiki/Montmorillonite montmorillonite]), [https://en.wikipedia.org/wiki/Vermiculite vermiculite] and [https://en.wikipedia.org/wiki/Bentonite bentonite]. Their basic building blocks are sheets of silica (Si) tetrahedra and oxygen (O) and hydroxyl (OH) octahedra. Micas and clay minerals result originally from chemical weathering of igneous rocks and feldspars. For example, weathering of gabbro or basalt releases smectite, while weathering of granite or rhyolite releases illite. Clay minerals are present in many sedimentary rocks, e.g., sandstone, greywacke, shale, mudstone, siltstone, and slate.  </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* Clay:  hydrous silicates that contain metal cations, generally aluminum. Most common clay minerals are [https://en.wikipedia.org/wiki/Kaolinite kaolinite]  (Al<sub>2</sub>Si<sub>2</sub>O<sub>5</sub>(OH)<sub>4</sub>), [https://en.wikipedia.org/wiki/Illite illite], [https://en.wikipedia.org/wiki/Smectite smectite] (incl. [https://en.wikipedia.org/wiki/Montmorillonite montmorillonite]), [https://en.wikipedia.org/wiki/Vermiculite vermiculite] and [https://en.wikipedia.org/wiki/Bentonite bentonite]. Their basic building blocks are sheets of silica (Si) tetrahedra and oxygen (O) and hydroxyl (OH) octahedra. Micas and clay minerals result originally from chemical weathering of igneous rocks and feldspars. For example, weathering of gabbro or basalt releases smectite, while weathering of granite or rhyolite releases illite<ins class="diffchange diffchange-inline"><ref>Zhao, T., Xu, S. and Hao, F. 2023. Differential adsorption of clay minerals: Implications for organic matter enrichment. Earth-Science Reviews 246, 104598</ref></ins>. Clay minerals are present in many sedimentary rocks, e.g., sandstone, greywacke, shale, mudstone, siltstone, and slate.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The specific densities (density relative to water <math>s=\rho_{mineral}/\rho_{water}</math>) of these minerals is given in Table 2.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The specific densities (density relative to water <math>s=\rho_{mineral}/\rho_{water}</math>) of these minerals is given in Table 2.</div></td></tr>
</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=80561&oldid=prevDronkers J at 12:00, 16 December 20232023-12-16T12:00:31Z<p></p>
<a href="https://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=80561&oldid=80308">Show changes</a>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=80308&oldid=prevDronkers J at 15:49, 2 July 20232023-07-02T15:49:37Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 15:49, 2 July 2023</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l190" >Line 190:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Deposition of sediment on the seabed takes place when conditions are suitable. These conditions are different for each type of sediment.  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Deposition of sediment on the seabed takes place when conditions are suitable. These conditions are different for each type of sediment.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>When a sediment-laden water mass reaches an area of lower flow strength and wave activity, part of the carried material is deposited. Sediment particles with the greatest fall velocity settle first and particles entrained as bedload (rolling and jumping along the bottom) come to rest. When the current strength and wave activity further decrease, the fine suspended material also settles. Most sedimentation takes place in the period around slack <del class="diffchange diffchange-inline">tide </del>(flow reversal). Part of the deposited material will afterwards be resuspended by the recovering tidal flow, but another part will remain. This can lead to temporary or permanent deposition. Deposits are temporary if they are insufficiently consolidated and re-eroded during conditions of strong currents (e.g., spring tide) or strong wave action (storm). Permanent deposits have a layered character; each layer represents a deposition period. Successive layers may contain different types of sediment if they have been deposited under different conditions. The layered sediment deposits in estuarine channels sometimes exhibit thin intermediate mud drapes deposited in short periods around high-water or low-water slack tide<del class="diffchange diffchange-inline">)</del><ref name=MB>Martinius, A.W. and van den Berg, J.H. 2011. Atlas of sedimentary structures in estuarine and tidally influenced river deposits of the Rhine-Meuse-Scheldt system. EAGE Publ. ISBN 978-90-73834-11-8</ref>.  </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>When a sediment-laden water mass reaches an area of lower flow strength and wave activity, part of the carried material is deposited. Sediment particles with the greatest fall velocity settle first and particles entrained as bedload (rolling and jumping along the bottom) come to rest. When the current strength and wave activity further decrease, the fine suspended material also settles. Most sedimentation takes place in the period around <ins class="diffchange diffchange-inline">[[</ins>slack <ins class="diffchange diffchange-inline">water]] </ins>(flow reversal). Part of the deposited material will afterwards be resuspended by the recovering tidal flow, but another part will remain. This can lead to temporary or permanent deposition. Deposits are temporary if they are insufficiently consolidated and re-eroded during conditions of strong currents (e.g., spring tide) or strong wave action (storm). Permanent deposits have a layered character; each layer represents a deposition period. Successive layers may contain different types of sediment if they have been deposited under different conditions. The layered sediment deposits in estuarine channels sometimes exhibit thin intermediate mud drapes deposited in short periods around <ins class="diffchange diffchange-inline">[[Slack water|</ins>high-water or low-water slack tide<ins class="diffchange diffchange-inline">]]</ins><ref name=MB>Martinius, A.W. and van den Berg, J.H. 2011. Atlas of sedimentary structures in estuarine and tidally influenced river deposits of the Rhine-Meuse-Scheldt system. EAGE Publ. ISBN 978-90-73834-11-8</ref>.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Graded sediment===</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Graded sediment===</div></td></tr>
</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=79997&oldid=prevDronkers J at 19:01, 4 January 20232023-01-04T19:01:37Z<p></p>
<table class="diff diff-contentalign-left" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 19:01, 4 January 2023</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l306" >Line 306:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:GrainsizeBeachslope.jpg|thumb|400px|left|Figure 9: Relation between fall velocity (sediment type) and beach slope as a function of the Dean parameter <math>\Omega</math>. Redrawn after (Flemming and Fricke, 1983)<ref>Flemming, B.W. and Fricke, A.H. 1983. Beach and nearshore habitats as a function of internal geometry, primary sedimentary structures and grain size. In: McLachlan, A., Ersamus, T. (Eds.), Sandy Beaches as Ecosystems. Dr. W. Junk Publishers, The Hague, pp. 115–132</ref>.]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:GrainsizeBeachslope.jpg|thumb|400px|left|Figure 9: Relation between fall velocity (sediment type) and beach slope as a function of the Dean parameter <math>\Omega</math>. Redrawn after (Flemming and Fricke, 1983)<ref>Flemming, B.W. and Fricke, A.H. 1983. Beach and nearshore habitats as a function of internal geometry, primary sedimentary structures and grain size. In: McLachlan, A., Ersamus, T. (Eds.), Sandy Beaches as Ecosystems. Dr. W. Junk Publishers, The Hague, pp. 115–132</ref>.]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Sediments on the foreshore and subaerial beach are derived from nearby rivers or from ancient offshore river deposits. The foreshore is a highly energetic environment due to the activity of waves, which prevent settling of fine sediments. Sand and gravel are the dominant seabed sediments, depending on the supply of these sediments. The coarsest sediments are found in the breaker zone, especially in the higher part where the waves collapse on the beach. The finer fractions are found in the offshore zone and also on the backshore and the dunes, which are fed from the dry beach by aeolian transport. The type of sediment on the shoreface largely determines the equilibrium shoreface slope for a given wave climate. The relationship between sediment grain size, wave climate and <del class="diffchange diffchange-inline">shoreface </del>slope can be characterized by the Dean parameter  </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Sediments on the foreshore and subaerial beach are derived from nearby rivers or from ancient offshore river deposits. The foreshore is a highly energetic environment due to the activity of waves, which prevent settling of fine sediments. Sand and gravel are the dominant seabed sediments, depending on the supply of these sediments. The coarsest sediments are found in the breaker zone, especially in the higher part where the waves collapse on the beach. The finer fractions are found in the offshore zone and also on the backshore and the dunes, which are fed from the dry beach by aeolian transport. The type of sediment on the shoreface largely determines the equilibrium shoreface slope for a given wave climate. The relationship between sediment grain size, wave climate and <ins class="diffchange diffchange-inline">beach </ins>slope can be characterized by the Dean parameter  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><math>\Omega = H / (w T) ,  </math>  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><math>\Omega = H / (w T) ,  </math>  </div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:BeachSlopeGrainSizeData.jpg|thumb|400px|right|Figure 10: Correlation between sediment grainsize and related beach slope from 78 field studies, adapted from Bujan et al. (2019)<ref name=Bu>Bujan, N., Cox, R. and Masselink, G. 2019. From fine sand to boulders: Examining the relationship between beach-face slope and sediment size. Marine Geology 417, 106012</ref>. The violet area indicates the scatter of the data points.]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:BeachSlopeGrainSizeData.jpg|thumb|400px|right|Figure 10: Correlation between sediment grainsize and related beach slope from 78 field studies, adapted from Bujan et al. (2019)<ref name=Bu>Bujan, N., Cox, R. and Masselink, G. 2019. From fine sand to boulders: Examining the relationship between beach-face slope and sediment size. Marine Geology 417, 106012</ref>. The violet area indicates the scatter of the data points.]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Figure 9 suggests a positive correlation between sediment grainsize and beach slope. This is substantiated by a study of Bujan et al. (2019)<ref name=Bu></ref>, who compiled data on grainsize and associated beach slope (<math>\beta</math>) from a large number of field sites. The result is shown in Fig. 10, where the violet area represents more than 95% of the data points. The dark blue line is a fit to the observed values represented by the empirical relation <math>\tan \beta = -0.154(D_{50}-0.125)^{-0.145} + 0.268</math>. The large bandwidth around this line reflects the different characteristics of the field sites (wave climate, tides, beach profile, sediment sorting, ...) and the different data collection and analysis methods used in the underlying studies. Grainsize and beach slope are positively correlated. For large grainsizes, [[Swash zone dynamics|wave up- and downrush]] is reduced by infiltration into the the sediment bed. This is a plausible explanation for the weak dependence of beach slope on grainsize for coarse sediment, compared to the strong dependence for fine-medium sediment<ref name=Bu></ref>.     </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Figure 9 suggests a positive correlation between sediment grainsize and beach slope <ins class="diffchange diffchange-inline">(the beach slope is defined as the average slope of the beach face, the zone between the low-water line and the beach berm)</ins>. This is substantiated by a study of Bujan et al. (2019)<ref name=Bu></ref>, who compiled data on grainsize and associated beach slope (<math>\beta</math>) from a large number of field sites. The result is shown in Fig. 10, where the violet area represents more than 95% of the data points. The dark blue line is a fit to the observed values represented by the empirical relation <math>\tan \beta = -0.154(D_{50}-0.125)^{-0.145} + 0.268</math>. The large bandwidth around this line reflects the different characteristics of the field sites (wave climate, tides, beach profile, sediment sorting, ...) and the different data collection and analysis methods used in the underlying studies. Grainsize and beach slope are positively correlated. For large grainsizes, [[Swash zone dynamics|wave up- and downrush]] is reduced by infiltration into the the sediment bed. This is a plausible explanation for the weak dependence of beach slope on grainsize for coarse sediment, compared to the strong dependence for fine-medium sediment<ref name=Bu></ref>.     </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For a more detailed discussion of the shoreface equilibrium profile the reader is referred to the article [[Shoreface profile]], which deals with sandy coasts. Coasts with abundant fine sediment sources are dealt with in the article [[Coastal mud belt]]. <br clear=all></div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For a more detailed discussion of the shoreface equilibrium profile the reader is referred to the article [[Shoreface profile]], which deals with sandy coasts. Coasts with abundant fine sediment sources are dealt with in the article [[Coastal mud belt]]. <br clear=all></div></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l342" >Line 342:</td>
<td colspan="2" class="diff-lineno">Line 342:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Estuarine turbidity maximum]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Estuarine turbidity maximum]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Coastal mud belt]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Coastal mud belt]]</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">:[[Flocculation cohesive sediments]]</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">:[[Fluid mud]]</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
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</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=79822&oldid=prevDronkers J at 14:39, 31 August 20222022-08-31T14:39:58Z<p></p>
<table class="diff diff-contentalign-left" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
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<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 14:39, 31 August 2022</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l342" >Line 342:</td>
<td colspan="2" class="diff-lineno">Line 342:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Estuarine turbidity maximum]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Estuarine turbidity maximum]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Coastal mud belt]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:[[Coastal mud belt]]</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">:[[Flocculation cohesive sediments]]</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">:[[Fluid mud]]</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
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</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=79571&oldid=prevDronkers J at 11:39, 20 February 20222022-02-20T11:39:00Z<p></p>
<table class="diff diff-contentalign-left" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 11:39, 20 February 2022</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l162" >Line 162:</td>
<td colspan="2" class="diff-lineno">Line 162:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Fall velocity===</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Fall velocity===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:FallVelocityQuartz.jpg|thumb|300px|left|Figure 3: Fall velocity of quartz spheres (specific density <math>s=\rho/\rho_{water}=2.65</math>) in still water at temperature <math>\theta=20^{o}C</math>. The fall velocity at other temperatures <math>\theta</math> can be deduced by multiplying grainsizes <math>d[mm]</math> by <math>1-0.016*(\theta-20)</math>. ]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:FallVelocityQuartz.jpg|thumb|300px|left|Figure 3: Fall velocity of quartz spheres (specific density <math>s=\rho/\rho_{water}=2.65</math>) in still water at temperature <math>\theta=20^{o}C</math>. The fall velocity at other temperatures <math>\theta</math> can be deduced by multiplying grainsizes <math>d[mm]</math> by <math>1-0.016*(\theta-20)</math>. ]]</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l298" >Line 298:</td>
<td colspan="2" class="diff-lineno">Line 295:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Oceans===</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Oceans===</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The deep oceans have four main sediment sources <ref name=T></ref>:</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">[[File:SeafloorSediment.png|thumb|400px|right|Fig. 8. Distribution of sediment types on the seafloor. From [https://en.wikibooks.org/wiki/Historical_Geology/Marine_sediments Wikibooks].]]</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># Clastic fluvial sediments. Large quantities of fine sediments (silt, clay and fine sand) are deposited by the world's major rivers at the edges of the continental shelfs <del class="diffchange diffchange-inline">(see Fig. 1)</del>. These deposits destabilize the continental shelf slope, causing the sediment to slide down to the ocean floor by slumping or through gravity currents. These deposits are confined along the shelf break and are not further spread over the ocean floor.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The deep oceans have four main sediment sources <ref name=T></ref> <ins class="diffchange diffchange-inline">(Fig. 8)</ins>:</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Clastic fluvial sediments. Large quantities of fine sediments (silt, clay and fine sand) are deposited by the world's major rivers at the edges of the continental shelfs. These deposits destabilize the continental shelf slope, causing the sediment to slide down to the ocean floor by slumping or through gravity currents. These deposits are confined along the shelf break and are not further spread over the ocean floor.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Atmospheric dust. A large part of the fine sediments entrained by wind from arid land areas and ash from volcanic eruption plumes is deposited in the oceans (e.g., red clay deposits, manganese nodules). This contribution to ocean sedimentation is relatively small nowadays.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Atmospheric dust. A large part of the fine sediments entrained by wind from arid land areas and ash from volcanic eruption plumes is deposited in the oceans (e.g., red clay deposits, manganese nodules). This contribution to ocean sedimentation is relatively small nowadays.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Carbonaceous ooze. The remains of calcareous algae, mainly coccoliths and foraminifera, are a major component of the seafloor sediment in large parts of the ocean. Below depths of 3 to 4 km, however, they do not occur, because the scales dissolve here as a result of too high a pressure and too high a concentration of carbon dioxide.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Carbonaceous ooze. The remains of calcareous algae, mainly coccoliths and foraminifera, are a major component of the seafloor sediment in large parts of the ocean. Below depths of 3 to 4 km, however, they do not occur, because the scales dissolve here as a result of too high a pressure and too high a concentration of carbon dioxide.</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Beach and foreshore===</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Beach and foreshore===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[Image:GrainsizeBeachslope.jpg|thumb|400px|left|Figure <del class="diffchange diffchange-inline">8</del>: Relation between fall velocity (sediment type) and beach slope as a function of the Dean parameter <math>\Omega</math>. Redrawn after (Flemming and Fricke, 1983)<ref>Flemming, B.W. and Fricke, A.H. 1983. Beach and nearshore habitats as a function of internal geometry, primary sedimentary structures and grain size. In: McLachlan, A., Ersamus, T. (Eds.), Sandy Beaches as Ecosystems. Dr. W. Junk Publishers, The Hague, pp. 115–132</ref>.]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[Image:GrainsizeBeachslope.jpg|thumb|400px|left|Figure <ins class="diffchange diffchange-inline">9</ins>: Relation between fall velocity (sediment type) and beach slope as a function of the Dean parameter <math>\Omega</math>. Redrawn after (Flemming and Fricke, 1983)<ref>Flemming, B.W. and Fricke, A.H. 1983. Beach and nearshore habitats as a function of internal geometry, primary sedimentary structures and grain size. In: McLachlan, A., Ersamus, T. (Eds.), Sandy Beaches as Ecosystems. Dr. W. Junk Publishers, The Hague, pp. 115–132</ref>.]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Sediments on the foreshore and subaerial beach are derived from nearby rivers or from ancient offshore river deposits. The foreshore is a highly energetic environment due to the activity of waves, which prevent settling of fine sediments. Sand and gravel are the dominant seabed sediments, depending on the supply of these sediments. The coarsest sediments are found in the breaker zone, especially in the higher part where the waves collapse on the beach. The finer fractions are found in the offshore zone and also on the backshore and the dunes, which are fed from the dry beach by aeolian transport. The type of sediment on the shoreface largely determines the equilibrium shoreface slope for a given wave climate. The relationship between sediment grain size, wave climate and shoreface slope can be characterized by the Dean parameter  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Sediments on the foreshore and subaerial beach are derived from nearby rivers or from ancient offshore river deposits. The foreshore is a highly energetic environment due to the activity of waves, which prevent settling of fine sediments. Sand and gravel are the dominant seabed sediments, depending on the supply of these sediments. The coarsest sediments are found in the breaker zone, especially in the higher part where the waves collapse on the beach. The finer fractions are found in the offshore zone and also on the backshore and the dunes, which are fed from the dry beach by aeolian transport. The type of sediment on the shoreface largely determines the equilibrium shoreface slope for a given wave climate. The relationship between sediment grain size, wave climate and shoreface slope can be characterized by the Dean parameter  </div></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l312" >Line 312:</td>
<td colspan="2" class="diff-lineno">Line 310:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><math>\Omega = H / (w T) ,  </math>  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><math>\Omega = H / (w T) ,  </math>  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>where <math>H</math> is the significant offshore wave height (before breaking), <math>w</math> the sediment fall velocity and <math>T</math> the peak wave period. This relationship is schematically shown in Fig. <del class="diffchange diffchange-inline">8</del>.  </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>where <math>H</math> is the significant offshore wave height (before breaking), <math>w</math> the sediment fall velocity and <math>T</math> the peak wave period. This relationship is schematically shown in Fig. <ins class="diffchange diffchange-inline">9</ins>.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[Image:BeachSlopeGrainSizeData.jpg|thumb|400px|right|Figure <del class="diffchange diffchange-inline">9</del>: Correlation between sediment grainsize and related beach slope from 78 field studies, adapted from Bujan et al. (2019)<ref name=Bu>Bujan, N., Cox, R. and Masselink, G. 2019. From fine sand to boulders: Examining the relationship between beach-face slope and sediment size. Marine Geology 417, 106012</ref>. The violet area indicates the scatter of the data points.]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[Image:BeachSlopeGrainSizeData.jpg|thumb|400px|right|Figure <ins class="diffchange diffchange-inline">10</ins>: Correlation between sediment grainsize and related beach slope from 78 field studies, adapted from Bujan et al. (2019)<ref name=Bu>Bujan, N., Cox, R. and Masselink, G. 2019. From fine sand to boulders: Examining the relationship between beach-face slope and sediment size. Marine Geology 417, 106012</ref>. The violet area indicates the scatter of the data points.]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Figure <del class="diffchange diffchange-inline">8 </del>suggests a positive correlation between sediment grainsize and beach slope. This is substantiated by a study of Bujan et al. (2019)<ref name=Bu></ref>, who compiled data on grainsize and associated beach slope (<math>\beta</math>) from a large number of field sites. The result is shown in Fig. <del class="diffchange diffchange-inline">9</del>, where the violet area represents more than 95% of the data points. The dark blue line is a fit to the observed values represented by the empirical relation <math>\tan \beta = -0.154(D_{50}-0.125)^{-0.145} + 0.268</math>. The large bandwidth around this line reflects the different characteristics of the field sites (wave climate, tides, beach profile, sediment sorting, ...) and the different data collection and analysis methods used in the underlying studies. Grainsize and beach slope are positively correlated. For large grainsizes, [[Swash zone dynamics|wave up- and downrush]] is reduced by infiltration into the the sediment bed. This is a plausible explanation for the weak dependence of beach slope on grainsize for coarse sediment, compared to the strong dependence for fine-medium sediment<ref name=Bu></ref>.     </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Figure <ins class="diffchange diffchange-inline">9 </ins>suggests a positive correlation between sediment grainsize and beach slope. This is substantiated by a study of Bujan et al. (2019)<ref name=Bu></ref>, who compiled data on grainsize and associated beach slope (<math>\beta</math>) from a large number of field sites. The result is shown in Fig. <ins class="diffchange diffchange-inline">10</ins>, where the violet area represents more than 95% of the data points. The dark blue line is a fit to the observed values represented by the empirical relation <math>\tan \beta = -0.154(D_{50}-0.125)^{-0.145} + 0.268</math>. The large bandwidth around this line reflects the different characteristics of the field sites (wave climate, tides, beach profile, sediment sorting, ...) and the different data collection and analysis methods used in the underlying studies. Grainsize and beach slope are positively correlated. For large grainsizes, [[Swash zone dynamics|wave up- and downrush]] is reduced by infiltration into the the sediment bed. This is a plausible explanation for the weak dependence of beach slope on grainsize for coarse sediment, compared to the strong dependence for fine-medium sediment<ref name=Bu></ref>.     </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For a more detailed discussion of the shoreface equilibrium profile the reader is referred to the article [[Shoreface profile]], which deals with sandy coasts. Coasts with abundant fine sediment sources are dealt with in the article [[Coastal mud belt]]. <br clear=all></div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For a more detailed discussion of the shoreface equilibrium profile the reader is referred to the article [[Shoreface profile]], which deals with sandy coasts. Coasts with abundant fine sediment sources are dealt with in the article [[Coastal mud belt]]. <br clear=all></div></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l323" >Line 323:</td>
<td colspan="2" class="diff-lineno">Line 321:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Estuaries===</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Estuaries===</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The sediment distribution in estuaries is particularly complex. Sediment deposits depend on the supply of river sediment, the supply of sediment from the sea and on local flow and wave conditions, in relation with a generally intricate topography. In addition, deposits are influenced by strong fluctuations in river discharge, tides and wave conditions at various timescales. Nevertheless, the sediment distribution in estuaries generally displays a characteristic pattern that is shown in Fig. <del class="diffchange diffchange-inline">10 </del>and discussed below.  </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The sediment distribution in estuaries is particularly complex. Sediment deposits depend on the supply of river sediment, the supply of sediment from the sea and on local flow and wave conditions, in relation with a generally intricate topography. In addition, deposits are influenced by strong fluctuations in river discharge, tides and wave conditions at various timescales. Nevertheless, the sediment distribution in estuaries generally displays a characteristic pattern that is shown in Fig. <ins class="diffchange diffchange-inline">11 </ins>and discussed below.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[Image:EstuarineBedSedimentDistribution.jpg|thumb|700px|center|Figure <del class="diffchange diffchange-inline">10</del>: Typical example of the spatial distribution of bed sediments in a coastal plain estuary, schematically represented (not at scale). Adapted from Dalrymple et al. (1992)<ref>Dalrymple, R.W., Zaitlin, B.A., Boyd, R., 1992. Estuarine facies models: conceptual basis and stratigraphic implications. Journal of Sedimentary Petrology 62, 1130–1146 </ref>.]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[Image:EstuarineBedSedimentDistribution.jpg|thumb|700px|center|Figure <ins class="diffchange diffchange-inline">11</ins>: Typical example of the spatial distribution of bed sediments in a coastal plain estuary, schematically represented (not at scale). Adapted from Dalrymple et al. (1992)<ref>Dalrymple, R.W., Zaitlin, B.A., Boyd, R., 1992. Estuarine facies models: conceptual basis and stratigraphic implications. Journal of Sedimentary Petrology 62, 1130–1146 </ref>.]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=79306&oldid=prevDronkers J at 13:16, 4 October 20212021-10-04T13:16:45Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 13:16, 4 October 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l199" >Line 199:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Sediment deposits in coastal areas are not always layered; mixed deposits occur frequently. These deposits are referred to as graded sediment. Layered sediment deposits can be mixed when the seabed is strongly perturbated. Mixing also takes place through bioturbation: soil animals (mainly worms and molluscs) bring material from deeper layers to the surface through ingestion and excretion <ref>Baumfalk, Y.A. 1979. Heterogeneous grain size distribution in tidal flat sediment caused by bioturbation activity of Arenicola marina (polychaeta). Netherlands Journal of Sea Research 13: 428-440</ref><ref> Gallagher, E.D. 2008. Bioturbation. Biol. Ocean. Processes, EEOS 630</ref>. Deposition of mixed sediment also takes place by excretion of filter feeders in the form of fecal pellets. Terminology for mixed deposits is indicated in Fig. 5 for different mixtures of gravel, sand and mud. Mud is itself a mixture of particles with a grain size of less than 0.063 mm, consisting of very fine sand, silt, clay and organic matter.  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Sediment deposits in coastal areas are not always layered; mixed deposits occur frequently. These deposits are referred to as graded sediment. Layered sediment deposits can be mixed when the seabed is strongly perturbated. Mixing also takes place through bioturbation: soil animals (mainly worms and molluscs) bring material from deeper layers to the surface through ingestion and excretion <ref>Baumfalk, Y.A. 1979. Heterogeneous grain size distribution in tidal flat sediment caused by bioturbation activity of Arenicola marina (polychaeta). Netherlands Journal of Sea Research 13: 428-440</ref><ref> Gallagher, E.D. 2008. Bioturbation. Biol. Ocean. Processes, EEOS 630</ref>. Deposition of mixed sediment also takes place by excretion of filter feeders in the form of fecal pellets. Terminology for mixed deposits is indicated in Fig. 5 for different mixtures of gravel, sand and mud. Mud is itself a mixture of particles with a grain size of less than 0.063 mm, consisting of very fine sand, silt, clay and organic matter.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>See also: [[Biogeomorphology of <del class="diffchange diffchange-inline">aquatic </del>systems]], [[Sandy shore habitat]], [[Meiofauna of Sandy Beaches]].</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>See also: [[Biogeomorphology of <ins class="diffchange diffchange-inline">coastal </ins>systems]], [[Sandy shore habitat]], [[Meiofauna of Sandy Beaches]].</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Spontaneous segregation of graded sediment can occur under certain conditions. This segregation generates contiguous patches of different types of sediment. The underlying feedback mechanism links sedimentation of fine material on a smooth muddy seabed to a locally reduced degree of turbulence <ref> Murray, A.B. and Thieler, E.R. 2004. A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and ‘rippled scour depressions’. Continental Shelf Res. 24: 295-315</ref>. As a result, fine material will mainly deposit in places where fine material already dominates on the seabed, so that these muddy patches increase in size and in mud content. This continues until no fine material is available any more from neighboring patches of coarser deposits from which the fines have been winnowed.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Spontaneous segregation of graded sediment can occur under certain conditions. This segregation generates contiguous patches of different types of sediment. The underlying feedback mechanism links sedimentation of fine material on a smooth muddy seabed to a locally reduced degree of turbulence <ref> Murray, A.B. and Thieler, E.R. 2004. A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and ‘rippled scour depressions’. Continental Shelf Res. 24: 295-315</ref>. As a result, fine material will mainly deposit in places where fine material already dominates on the seabed, so that these muddy patches increase in size and in mud content. This continues until no fine material is available any more from neighboring patches of coarser deposits from which the fines have been winnowed.</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* Consolidation. Fine sediment can be easily resuspended when it has just been deposited. Freshly deposited fine sediment has a large pore volume filled with seawater that can be set in motion under the influence of horizontal pressure gradients of the surface water. Over time, the seawater is forced out of the pores by the weight of the consolidating deposit. The bulk density of the deposit increases while the permeability decreases. This causes a sharp increase of the critical shear stress for erosion<ref name=M21>Mohr, H., Draper, S., White, D.J. and Cheng, L. 2021. The effect of permeability on the erosion threshold of fine-grained sediments. Coastal Engineering 163, 103813</ref>.  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* Consolidation. Fine sediment can be easily resuspended when it has just been deposited. Freshly deposited fine sediment has a large pore volume filled with seawater that can be set in motion under the influence of horizontal pressure gradients of the surface water. Over time, the seawater is forced out of the pores by the weight of the consolidating deposit. The bulk density of the deposit increases while the permeability decreases. This causes a sharp increase of the critical shear stress for erosion<ref name=M21>Mohr, H., Draper, S., White, D.J. and Cheng, L. 2021. The effect of permeability on the erosion threshold of fine-grained sediments. Coastal Engineering 163, 103813</ref>.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* Clay content of the deposit. The molecular structure of clay particles enables the formation of electrochemical bonds that significantly increase the resistance of the deposit against erosion. This effect already occurs at a clay content of just 10%. A deposit with a sufficiently high clay content retains the water for a long time and consolidates slowly. Once consolidated, the deposit forms a hard layer that can withstand very high shear stresses. See [[Sediment deposition and erosion processes]] for further details.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* Clay content of the deposit. The molecular structure of clay particles enables the formation of electrochemical bonds that significantly increase the resistance of the deposit against erosion. This effect already occurs at a clay content of just 10%. A deposit with a sufficiently high clay content retains the water for a long time and consolidates slowly. Once consolidated, the deposit forms a hard layer that can withstand very high shear stresses. See [[Sediment deposition and erosion processes]] for further details.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* Biota. Living organisms can strongly alter the erosion strength of seabed deposits. Various large organic molecules, called EPS (extracellular polymeric substances), secreted by micro-organisms, bind sediment particles together and form biofilms at the sediment surface, especially in intertidal areas. Erosion resistance of sediment deposits is also favored by the formation of microbial mats, often called algal mats. Erosion resistance is diminished by other organisms, bivalves in particular, that disturb the sediment bed by so-called bioturbation and graze on microalgae. More details can be found in [[Biogeomorphology of <del class="diffchange diffchange-inline">aquatic </del>systems]].</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* Biota. Living organisms can strongly alter the erosion strength of seabed deposits. Various large organic molecules, called EPS (extracellular polymeric substances), secreted by micro-organisms, bind sediment particles together and form biofilms at the sediment surface, especially in intertidal areas. Erosion resistance of sediment deposits is also favored by the formation of microbial mats, often called algal mats. Erosion resistance is diminished by other organisms, bivalves in particular, that disturb the sediment bed by so-called bioturbation and graze on microalgae. More details can be found in [[Biogeomorphology of <ins class="diffchange diffchange-inline">coastal </ins>systems]].</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The amount of sediment <math>E</math> [kg s<sup>-1</sup>m<sup>-2</sup>] that is brought in suspension when the shear stress <math>\tau</math> exceeds the critical stress <math>\tau_{cr}</math> for initiation of erosion, primarily depends on the excess shear stress <math>\tau - \tau_{cr}</math>. However, it also depends on many other factors. For fine non-cohesive sand, the relation can be represented by the empirical formula<ref> Mehta, A. J. and Partheniades, E. 1982. Resuspension of deposited cohesive sediment beds. Procs. 18th International Conference on Coastal Engineering, Cape Town, South Africa</ref></div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The amount of sediment <math>E</math> [kg s<sup>-1</sup>m<sup>-2</sup>] that is brought in suspension when the shear stress <math>\tau</math> exceeds the critical stress <math>\tau_{cr}</math> for initiation of erosion, primarily depends on the excess shear stress <math>\tau - \tau_{cr}</math>. However, it also depends on many other factors. For fine non-cohesive sand, the relation can be represented by the empirical formula<ref> Mehta, A. J. and Partheniades, E. 1982. Resuspension of deposited cohesive sediment beds. Procs. 18th International Conference on Coastal Engineering, Cape Town, South Africa</ref></div></td></tr>
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</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Coastal_and_marine_sediments&diff=79191&oldid=prevDronkers J at 16:02, 17 August 20212021-08-17T16:02:00Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Definition|title=Marine sediment  </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Definition|title=Marine sediment  </div></td></tr>
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