Similarity Curves as Indicators of Stratigraphic Discontinuities
Hilary Clement Olson, Anthony Gary, Garry D. Jones, 2003. "Similarity Curves as Indicators of Stratigraphic Discontinuities", Micropaleontologic Proxies for Sea-Level Change and Stratigraphic Discontinuities, Hilary Clement Olson, R. Mark Leckie
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An unconventional application of traditional similarity coefficients, the similarity curve, is presented to assist in the identification and interpretation of stratigraphic discontinuities. Similarity curves are generated for an entire stratigraphic sequence by comparing each sample to the sample immediately above it in stratigraphic sequence. Similarity coefficients are calculated for each sample pair on the basis of their contained foraminiferal assemblages, and a similarity curve is then generated for the stratigraphic section. By examining the breaks in these curves and comparing the total assemblage similarity curve to similarity curves generated individually for planktonic and benthic groups, we interpret candidates for discontinuities from a well in the Gulf of Mexico. Furthermore, we discuss these discontinuities and relate them to factors such as potential sea-level change, changes in sedimentation locus, and dissolution effects.
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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.