Physical Sciences and Mathematics Commons^™

The Diatom Dark Ages: Identification Of Mid-Cretaceous Arctic Platform Diatoms From The Basal Transgression Of The Kanguk Formation, Devon Island, Nunavut, Canada, Megan Heins

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The lower part of the mid-Cretaceous Kanguk Formation (Lower Turonian interval) contains an important paleontological record crucial to the characterization of a poorly known interval of fossil marine diatoms history. Kanguk Formation mudstones are exposed in a ~200 m-thick section on Devon Island, Nunavut, Canadian High Arctic. Diatoms at this location are well-preserved due to shallow burial on this Arctic Platform site. The rock sequence was protected from glacial erosion that removed much of the Cretaceous record by being down-faulted in a linear graben. Study of these well-preserved fossil diatoms allows for a documentation of the assemblage, identification of potentially …

Stratigraphy And Sedimentology Of The Cretaceous Mowry Shale In The Northern Bighorn Basin Of Wyoming: Implications For Unconventional Resource Exploration And Development, Jordan M. Bremer

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Mowry Shale (Albian-Cenomanian) is an extensive mudrock dominated unit historically believed to represent a single, long-term deep water sequence within the Western Cordilleran Foreland Basin of North America. While the Mowry Shale has received study for almost a century, detailed stratigraphic context is still lacking. Such an understanding will be required as the formation is increasingly explored as an unconventional resource play.

This study examines the stratigraphy of the interval between the Muddy sandstone and the Frontier Formation, focusing on the Mowry Shale both at outcrop and in the subsurface of the Bighorn Basin of northwestern Wyoming. Detailed measured …

Upper Albian To Lower Cenomanian Calcareous Nannofossil Biostratigraphy Of The Proto-North Atlantic, Shamar Chin

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Lower Cenomanian calcareous nannofossil assemblages from Deep Sea Drilling Project (DSDP) Sites 137 and 547 in the proto-North Atlantic Ocean were analyzed quantitatively to examine the fidelity of the widely used CC and UC calcareous nannofossil Zonal schemes. Datasets from Ocean Drilling Program (ODP) holes 1050C and 1052E (Blake Nose) and Tanzania Drilling Project (TDP) Site 24 were integrated into this dataset. Four biozones spanning the upper Albian through middle Cenomanian were determined using the method of unitary associations (UA). Data were also used from these sequences to generate a ranking and scaling (RASC) optimum sequence. A new reliability index …

Plankton Evolution Driven By Paleoceanographic Change: Prediscosphaera From The Mid-Cretaceous In The Western North Atlantic, Kristen L. Mitchell

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Well-preserved nannofossil assemblages in late Albian and Cenomanian hemipelagic sections from Ocean Drilling Program (ODP) Leg 171B preserve a record of the early history and adaptive radiation of the calcareous nannofossil genus Prediscosphaera. There was a significant rise in the abundance of the genus (from an average of 2% in the early late Albian to about 6% in the latest Albian and Cenomanian. This rise, and other shorter term pulses of increased generic abundance, corresponds to black shale deposition episodes. Twelve distinct morphotypes that were derived from the long-ranging Prediscosphera columnata and Prediscosphaera spinosa, are recognized and differentiated …

Stratigraphy, Sedimentology, And Ichnology Of The Upper Cretaceous Frontier Formation In The Alkali Anticline Region, Bighorn County, Wyoming, Charles K. Clark

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Upper Cretaceous Frontier Formation was studied along two strike-parallel cliff-lines in the Alkali Anticline region of the northeastern Bighorn Basin, Bighorn County, Wyoming. The unit comprises up to 145 m of mudrock, sandstone, conglomerate, and volcanic fallout sediments deposited along the western margin of the Cretaceous Western Interior Seaway (KWIS) in the mid- to late-Cenomanian. Eighteen facies, comprising six facies associations are identified from physical and biogenic sedimentary features. Sediments were deposited in open marine offshore to shoreface and subaqueous deltaic to delta platform environments. The observed trace fossil suites record departures from the archetypal ichnofacies. Such departures record …