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Spatial characterization of Western Interior Seaway paleoceanography using foraminifera, fuzzy sets and Dempster-Shafer theory
Lockshin, Sam

2016, Master of Science (MS), Bowling Green State University, Geology.
The spatial paleoceanography of the entire Western Interior Seaway (WIS) during the
Cenomanian-Turonian Oceanic Anoxic Event has been reconstructed quantitatively for the first
time using Geographic Information Systems. Models of foraminiferal occurrences—derived
from Dempster-Shafer theory and driven by fuzzy sets of stratigraphic and spatial data—reflect
water mass distributions during a brief period of rapid biotic turnover and oceanographic
changes in a greenhouse world. Dempster-Shafer theory is a general framework for approximate
reasoning based on combining information (evidence) to predict the probability (belief) that any
phenomenon may occur. Because of the inherent imprecisions associated with paleontological
data (e.g., preservational and sampling biases, missing time, reliance on expert knowledge),
especially at fine-scale temporal resolutions, Dempster-Shafer theory is an appropriate technique
because it factors uncertainty directly into its models. Locality data for four benthic and one
planktic foraminiferal species and lithologic and geochemical data from sites distributed
throughout the WIS were compiled from four ammonoid biozones of the Upper Cenomanian and
Early Turonian stages. Of the 14 environmental parameters included in the dataset, percent silt,
percent total carbonate, and depositional environment (essentially water depth) were associated
with foraminiferal occurrences. The inductive Dempster-Shafer belief models for foraminiferal
occurrences reveal the positions of northern and southern water masses consistent with the
oceanographic gyre circulation pattern that dominated in the seaway during the Cenomanian-
Turonian Boundary Event. The water-mixing interface in the southwestern part of the WIS was
mostly restricted to the Four Corners region of the US, while the zone of overlap of northern and
southern waters encompassed a much larger area along the eastern margin, where southern
waters occasionally entered from the tropics. In addition to its paleospatial significance, this
study introduces a rigorous, quantitative methodology with which to analyze paleontological
occurrence data, assess the degree of uncertainty and prioritize regions for additional data
collection.
Margaret Yacobucci, Dr. (Advisor)
Peter Gorsevski, Dr. (Committee Member)
Andrew Gregory, Dr. (Committee Member)
132 p.

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Lockshin, S. (2016). Spatial characterization of Western Interior Seaway paleoceanography using foraminifera, fuzzy sets and Dempster-Shafer theory. (Electronic Thesis or Dissertation). Retrieved from https://etd.ohiolink.edu/

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Lockshin, Sam. "Spatial characterization of Western Interior Seaway paleoceanography using foraminifera, fuzzy sets and Dempster-Shafer theory." Electronic Thesis or Dissertation. Bowling Green State University, 2016. OhioLINK Electronic Theses and Dissertations Center. 10 Dec 2017.

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Lockshin, Sam "Spatial characterization of Western Interior Seaway paleoceanography using foraminifera, fuzzy sets and Dempster-Shafer theory." Electronic Thesis or Dissertation. Bowling Green State University, 2016. https://etd.ohiolink.edu/

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