Foraminifera as Proxies for Sea-Level Change on Siliciclastic Margins
R. Mark Leckie, Hilary Clement Olson, 2003. "Foraminifera as Proxies for Sea-Level Change on Siliciclastic Margins", Micropaleontologic Proxies for Sea-Level Change and Stratigraphic Discontinuities, Hilary Clement Olson, R. Mark Leckie
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Foraminifera of siliciclastic and mixed siliciclastic–carbonate continental margins are sensitive to changes in sea level because of the complex biological, chemical, and physical oceanographic variables that help to shape foraminiferal niche space. Data on foraminiferal distribution and abundance provide useful proxies for paleoenvironment. Here we emphasize the importance of salinity, temperature, seasonality, food supply (productivity), and dissolved oxygen in controlling the nature of marginal marine, neritic, and upper bathyal foraminiferal biofacies. We also elaborate on the paleoecologic significance and utility of using planktic:benthic ratios, diversity indices, and similarity coefficients for interpreting changes in relative sea level. The recognition and correlation of the systems tracts that define sequence stratigraphic architecture reliably hinge on multi-proxy micropaleontologic evidence, particularly that provided by benthic and planktic foraminifera, coupled with sedimentology and geochemistry.
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Micropaleontology and biostratigraphy play vital roles for deciphering the stratigraphic record produced by changes in relative sea level, interpreting the history of global sea-level change, and testing models for the causes of sea-level fluctuations due to the variable influences of tectonics, glacio-eustasy, and climate. The stratigraphic architecture developed in response to changing eustasy, accommodation space, and sediment supply along continental margins, in epicontinental seas, and on carbonate platforms can be interpreted using the tools of marine micropaleontology. Microfossils provide chronostratigraphic control and a wealth of paleoenvironmental information about depositional environments as well as post-depositional changes to those environments. This volume demonstrates clearly that micropaleontologic proxies of environmental change provide a powerful dimension to the interpretive potential of stratigraphic sequences produced by changes in relative sea level and eustasy. Studies in the volume range from paralic to bathyal environments, span Pennsylvanian through Holocene stratigraphy, encompass a variety of microfossil groups and include a wide spectrum of techniques and paleoenvironmental proxies. The volume has been designed for graduate students and professionals interested in a wide range of subjects.