Sediment continental margin

Sloss, L. L. and Speed, R. C. (1974). Relationships of cratonic and continental-margin tectonic episodes. In "Tectonics and Sedimentation" (W. R. Dickenson, ed.), pp. 98-119. Society of Economic Paleontologists and Mineralogists, Tulsa, Oklahoma, SEPM Special Publication 22. 

Anschutz, P., Zihong, S., Sundby, B., Mucci, A., and Gobeil, C. (1998). Burial efficiency of phosphorus and the geochemistry of iron in continental margin sediments. Limnol. Oceanogr. 43,53-64. 

Ruttenberg, K. C. and Berner, R. A. (1993). Authigenic apatite formation and burial in sediments from non-upwelling, continental margin environments. Geochim. Cosmochim. Acta 57,991-1007. 

Heussner S, Cherry RD, Heyraud M (1990) Po-210 and Pb-210 in sediment trap particles on a Mediterranean continental margin. Cont. Shelf Res 10 989-100 Heyraud M, Cherry RD (1983) Correlation of Po-210 and Pb-210 enrichments in the sea-surface microlayer with neuston biomass. Cont Shelf Res 1 283-293 Honeyman BD, Santschi PH (1989)The role of particles and colloids in the transport of radionuclides and trace metals in the oceans. In Environmental particles. Buffle J, van Leewen HP (eds) Lewis Publishers, Boca Raton, p 379-423... 

Other applications of °Thxs profiling to assess accumulation rates of sedimentary components include carbonate accumulation in the Western Equatorial Atlantic (Rtihlemann et al. 1996) biogenic and terriginous particle accumulation on the Australian continental margin (Veeh et al. 2000) sedimentation rates in the North East Atlantic (McManus et al. 1998 Thomson et al. 1993 ) (Fig. 5) sedimentation rates during key... 

Thamdrup B, Canfield DE (1996) Pathways of carbon oxidation in continental margin sediments off central Chile. Limnol Oceanogr 41 1629-1650... 

Table 12.3 Electron Acceptors in (a) Pelagic Sediments and (b) Continental Margin Sediments. ... 

Some of the clays that enter the ocean are transported by river input, but the vast majority of the riverine particles are too large to travel fer and, hence, settle to the seafloor close to their point of entry on the continental margins. The most abundant clay minerals are illite, kaolinite, montmorillonite, and chlorite. Their formation, geographic source distribution and fete in the oceans is the subject of Chapter 14. In general, these minerals tend to undergo little alteration until they are deeply buried in the sediments and subject to metagenesis. 

Where the waves and currents weaken, resuspended sediment settles back down to the seafloor. Given the small particle sizes of the suspended material (mostly 3 to 10 pm), redeposition can take many years. The resulting redistribution of sediments creates patches of clay, mud, and exposed rock on the continental margins. In other words, resuspension from waves and currents can cause some sediments to become reUct deposits. Hard bottoms can serve as good habitats for some members of the benthos as they promote the formation of coral reefs. For paleoceanographers, relict deposits are problematic because they represent gaps, or imconformities, in the sedimentary record. 

Turbidity and contour currents resuspend and transport the sediments that lie on the continental margin. These sediments are redeposited when the currents weaken. 

Based on thermodynamic considerations, sediments that lie at depths below the saturation horizon should have 0% CaCOj. This then explains why calcareous oozes are restricted to sediments lying on top of the mid-ocean ridges and rises and why the sediments of the North Pacific are nearly devoid of calcite and aragonite. (The low %CaCOj in the sediments of the continental margin is a result of dilution by terrestrial clay minerals.)... 

The geographic distribution of opal in the surfece sediments is controlled by (1) the local rain rate of biogenic silica, (2) the degree of its preservation in the sediments, and (3) the relative rate of accumulation of other types of particles. Preservation is promoted by rapid burial as this isolates BSi from seawater. But if the BSi is buried by other particle types, the relative contribution of BSi to the sediment is diluted. This dilution effect causes the BSi content of most continental margin sediments to be low despite high rain rates. Preservation efficiency is also dependent on (1) the intensity of bioturbation and suspension feeding and (2) the various factors that control... 

Significant amounts of manganese and phosphorite deposits are present on the top of the Blake Plateau, which lies at the foot of the continental margin off the southeastern United States at depths of 500 to 900 m. The Gulf Stream has eroded most of the unconsolidated sediments at this location, leaving only a carbonate platform, which has become covered with pavements of manganese and phosphorite covering an area of 5000 km ... 

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