Cretaceous marine invertebrates: A geochemical perspective.

Cretaceous marine invertebrates: A geochemical perspective.

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dc.contributor.advisor Veizer, J., en
dc.contributor.author Morrison, Joan Olivia. en
dc.date.accessioned 2009-03-23T16:03:15Z
dc.date.available 2009-03-23T16:03:15Z
dc.date.created 1991 en
dc.date.issued 2009-03-23T16:03:15Z
dc.identifier.citation Source: Dissertation Abstracts International, Volume: 53-03, Section: B, page: 1251. en
dc.identifier.isbn 9780315680470 en
dc.identifier.uri http://hdl.handle.net/10393/7784
dc.description.abstract A diagenetic evaluation was performed on marine fossil shell material from Cretaceous sediments of North America, the Arctic, the Antarctic and several localities in Europe. Trace element chemistry, XRD, SEM and stable isotope geochemistry were consistent in their results. Preservation of the original shell material of the low-Mg calcite organisms, brachiopods and belemnites, and the numerous aragonitic organisms was slightly variable with the majority of samples well preserved. Those samples that were altered underwent diagenetic stabilization in both reducing and oxic environments. Using the chemical data from only well preserved fossil shell material, basin paleo-reconstructions showed that from Aptian to Maastrichtian time, the Cretaceous seas were generally aerobic with some dysaerobia evident at the sediment/water interface and in the shallow sediment column. Paleosalinities fluctuated from brackish to normal marine, especially in the Western Interior Seaway of North America and the Paris Basin. The Lower Saxony basin, the Arctic and Antarctic were mainly normal marine with brackish conditions developing on occasion. Paleotemperatures determined from $\partial\sp $O data of preserved aragonite and low-Mg calcite shell material, also showed some variance. The Arctic and Antarctic were coolest, with Campanian/Maastrichtian temperatures about 12 or 13$\sp\circ$C, whereas the Lower Saxony basin and the Western Interior Seaway were slightly warmer, ranging from 11 to 20$\sp\circ$C. The Barremian/Aptian appeared to be the warmest time and a cooling trend was fairly consistent from then on. en
dc.format.extent 279 p. en
dc.publisher University of Ottawa (Canada). en
dc.subject.classification Paleontology. en
dc.title Cretaceous marine invertebrates: A geochemical perspective. en
dc.type Ph.D.Thesis (Ph.D.)--University of Ottawa (Canada), 1991. en

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