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Book ChapterDOI

Regional Clay Mineral Fades in Estuaries and Continental Margin of the United States East Coast

01 Jan 1972-Geological Society of America Memoirs (Geological Society of America)-Vol. 133, pp 293-316
About: This article is published in Geological Society of America Memoirs.The article was published on 1972-01-01. It has received 48 citations till now. The article focuses on the topics: Continental margin.
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Journal ArticleDOI
TL;DR: The history of sediment and its movement in the Atlantic drainage demonstrate some of the difficulties of modeling sediment on a river-basin scale as discussed by the authors, and large quantities of eroded material are still stored on hillslopes and in stream valleys where they continue to augment the sediment loads of the rivers.
Abstract: The history of sediment and its movement in the Atlantic drainage demonstrate some of the difficulties of modeling sediment on a river-basin scale. Soil erosion was accelerated by a factor of at least 10 when European settlers cleared forests and planted crops. Although increasing soil-conservation practice and decreasing crop farming have since reduced the rates of erosion, large quantities of eroded material are still stored on hillslopes and in stream valleys where they continue to augment the sediment loads of the rivers. The sediment from this episode of erosion that is largely past can be expected to emerge from storage for many decades and perhaps even several centuries to come. The reservoirs that have been built on many of the major rivers trap significant portions of the moving sediment which, in some places, may be remobilized by large floods. Essentially all the river sediment that reaches the Atlantic coastal zone is trapped in estuaries and coastal marshlands. Probably less than 5% is deposi...

446 citations

Book ChapterDOI
01 Jan 1978
TL;DR: The overall sedimentary sequence is therefore a potential record of coastal history; it may reveal complete successions from original estuary, delta, lagoon, or bay floors to the highest intertidal flat, including lateral variations in contemporaneous facies or subfacies as discussed by the authors.
Abstract: Salt marshes, which represent the final stage in the leveling of marine delta plains or the filling of depressions, embayments, and other irregularities along coasts, are to some extent a measure of coastal stability or equilibrium. The overall sedimentary sequence is therefore a potential record of coastal history; it may reveal complete successions from original estuary, delta, lagoon, or bay floors to the highest intertidal flat, including lateral variations in contemporaneous facies or subfacies. Associated mineral suites are equally important indicators of both sources and possible recycling of coastal sediments. As habitable dwelling space for numerous organisms, some of which are uniquely adapted to stressful conditions, salt marsh substrates record many details of significance in paleoecology, ichnology, and environmental reconstruction.

301 citations

Journal ArticleDOI
TL;DR: In this paper, a geochemical model for the covariation was developed, verified and used to guide the statistical modeling approach, which improved the comparability of metal levels in sediments by correcting for variable background concentrations that only serve to increase total data variability and reduce detection of spatial and temporal differences.

171 citations

Journal ArticleDOI
01 May 1988
TL;DR: In this article, sediment cores were collected from the continental shelf and slope along the SEEP-I transect (71°W) south of New England, and profiles of 210Pb and of 239,240Pu were measured in the cores.
Abstract: Sediment cores were collected from the continental shelf and slope along the SEEP—I transect (71°W) south of New England. Profiles of 210Pb and of239,240Pu were measured in the cores. Measurable amounts of Pu and of unsupported 210Pb occurred to the same depth in every core where both were measured, indicating that the distributions of tracers added to the slope sediments during the past 100 years are controlled by sediment mixing processes. Mixing coefficients of 0.14–1.0 cm2 y−1 were obtained from the210Pb and Pu distributions in slope sediments. A sediment mixing model that incorporates these mixing rates and a sedimentation rate of about 0.01 g cm−2 y−1 determined from other information predicts the measured distributions of DDT and related compounds in one core from the slope. An upper limit for the deposition of organic carbon in the slope sediments of 2.5 g C m−2 y−1 is obtained, significantly lower than earlier estimates. The measured 14C age of surface sediments is greater than predicted from a model for steady-state accumulation of planktonic detritus, suggesting that some of the carbon deposited on the slope is older reworked material, possibly derived from the continent or eroded from other marine deposits.

106 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the relationship of numerous genera and species to bottom-water environmental conditions such as dissolved oxygen and bottomwater temperatures, and found that ostracodes display a narrow depth zonation controlled by dissolved oxygen, and species diversity is high for a bathyal zone.

104 citations