Publication Date:
2018-06-06
Description:
Tidal currents and waves have caused some reworking and redistribution of Holocene sediments in the northern North Sea, with preferential deposition of fines in topographic depressions. This has led to a patchy distribution of sediments in terms of their textural, mineralogical and chemical composition. Nevertheless discernable relationships are found to exist between mean grain size and composition of the sediments. The relative abundance of biogenic components (primarily benthic Foraminifera) in the sand-size fraction of the sediments increases as mean grain size decreases, thus biogenic components are relatively more abundant in bathymetric lows. Coarse-grained sediments rich in detrital quartz show higher values of Si/ AI than do fine-grained sediments. Smectite is concentrated in the finest-grained sediments, whereas illite is relatively more abundant in coarser deposits. Thus clay mineral segregation processes previously reported to occur near river mouths also occur in an open shelf environment. Fine-grained, smectite-rich sediments show correspondingly higher values of Fe/ AI and lower values of K/ AI compared to the coarser deposits enriched in illite.
Type:
Article
,
NonPeerReviewed
Format:
text
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