Glacial marine sediments

King LH (1967) Isolation and Characterization of Organic Matter from Glacial-Marine Sediments on the Scotian Shelf. Report BIO 67-4, pp 1-18... 

Ice rafting is responsible for 7% of the terrigenous input of siliclastic particles to the ocean. When the ice melts, the particles settle to the seafloor to form glacial marine deposits. These are currently forming at latitudes greater than 40°N and 50° S. Most of the glacial marine sediments are poorly sorted deposits composed of relatively unweathered materials with chlorite being the dominant clay mineral. In the North Atlantic, layers... 

The continental shelves cover most of the seafloor in the Arctic Ocean, making this the shallowest ocean. Thus, most of the sediments are neritic. Because of light limitation, primary production is inhibited, so river runoff and ice rafting supply most of the particles to this ocean. As a result, lithogenous and glacial marine sediments are most common. 

Tillites The Mthified remains of unsorted glacial marine sediments. Contains large fragments of unweathered Mthogenous particles. 

Macpherson a. j. (1987) The Mackay Glacier/Granite Harbour system (Ross Dependency, Antarctica)—a study in near shore glacial marine sedimentation. Ph.D. Thesis, Victoria University of Wellington, New Zealand, 173 pp. 

PoweU, R.D. 1983. Glaciomarine sedimentation processes and Uthofacies of temperate tidewater glaciers in Glacier Bay, Alaska. In Glacial-Marine Sedimentation, Molnia, B.F., ed. Plenum Press, New York, pp. 185-232. 

Records of past environmental change are preserved in a broad range of Earth materials. Past environments are inferred from "proxy" records, meaning measurements of physical and chemical parameters of marine and terrestrial sediment, polar ice, and other materials that were in some way influenced by their environment during accumulation. Examples of proxy records are the distribution of glacial deposits, the isotopic composition of terrestrial and marine sediments and ice, the abundance and species composition of plant and animal fossils, and the width of tree rings. 

Yu E-F, Francois R, Bacon M (1996) Similar rates of modem and last-glacial ocean thermohaline circulation inferred from radiochemical data. Nature 379 689-694 Zheng Y, Anderson RF, van Geen A, Fleisher MQ (2002) Preservation of particulate non-lithogenic uranium in marine sediments. Geochim Cosmochim Acta 66(17) 3085-3092. 

Using the rock cycle as an example, we can compute the turnover time of marine sediments with respect to river input of solid particles from (1) the mass of solids in the marine sediment reservoir (1.0 x 10 g) and (2) the annual rate of river input of particles (1.4 X lO g/y). This yields a turnover time of (1.0 x 10 " g)/(14 x lO g/y) = 71 X lo y. On a global basis, riverine input is the major source of solids buried in marine sediments lesser inputs are contributed by atmospheric feUout, glacial ice debris, hydrothermal processes, and in situ production, primarily by marine plankton. As shown in Figure 1.2, sediments are removed from the ocean by deep burial into the seafloor. The resulting sedimentary rock is either uplifted onto land or subducted into the mantle so the ocean basins never fill up with sediment. As discussed in Chapter 21, if all of the fractional residence times of a substance are known, the sum of their reciprocals provides an estimate of the residence time (Equation 21.17). 

The neritic sediments surroimding the continent of Antarctica are dominated by glacial marine deposits. Divergence at 60°S causes oceanic upwelling, which transports cold, nutrient-rich waters to the euphotic zone. Since diatoms are the dominant phytoplankton, diatomaceous oozes encircle Antarctica between the latitudes 50° and 70°S. 

Mahowald, N., et al. (1999). Dust sources and deposition during the last glacial maximum and current climate A comparison of model results with paleodata from ice cores and marine sediments. 

Mahowald N., Kohfeld K., Hannson M., BaUcanski Y., Harrison S. P., Prentice I. C., Schulz M., and Rodhe H. (1999) Dust sources during the last glacial maximum and current climate a comparison of model results with paleodata from ice cores and marine sediments. J. Geophys. Res. 104, 15895-15916. 

The previous discussions focused on utilizing long-lived radioactive systems, either dissolved in seawater or in authigenic precipitates. Here we discuss its utility in silicate detritus or individual minerals in marine sediments to follow the history of northern hemisphere ice sheets during the last glacial period. This is merely one example of the powerful potential of radiogenic isotopes as provenance tracers wih paleoceanographic implication. 

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