Paleontology Commons^™

Depositional Model Of A Late Cretaceous Dinosaur Fossil Concentration, Lance Formation, Summer Rose Weeks

Loma Linda University Electronic Theses, Dissertations & Projects

A large Maastrichtian, nearly monospecific bonebed in the Lance Formation in eastern Wyoming has yielded 13,000 bones and fragments since 1996. Though excavation of the site continues, little is known of the circumstances and processes of deposition. This study aims to provide a depositional model for the bonebed. To accomplish this task we utilized 1D facies analysis of surrounding units and 3D analysis of the bonebed. The nature of the outcrop limited facies analysis to 1D. Four measured stratigraphic sections, each containing the bonebed unit, were taken and used in facies analysis. In addition, laterally continuous units were observed and …

The Growth And Ecology Of Upper Cambrian Microbialite Biostromes From The Notch Peak Formation In Utah, Ken P. Coulson

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure of carbonate rocks within the uplifted mountains of southwestern Utah presents a unique opportunity to study the growth, morphology and ecology of two upper Cambrian microbialite reefs located within the Hellnmaria Member of the Notch Peak Formation. The first reef contains meter-length, strongly elongate microbialites that grew in a deep, subtidal marine environment. These elongate microbialites formed as a result of coalescence of round ‘algal’ heads, a process known to produce compound microbialite structures in shallow water, but seldom explored as a key factor in the elongation of deep, subtidal forms that grew in ancient environments. The second reef …

Taphonomy Of A Lance Formation(Maastrichtian, Wy) Dinosaur Bonebed With A Focus On Tooth Traces, Matthew A. Mclain

Loma Linda University Electronic Theses, Dissertations & Projects

The Rose Quarry bonebed found in the Maastrichtian Lance Formation of eastern Wyoming possesses a complex blendof taphonomic signatures. Disarticulated, disassociated, fragmented bones of various states of abrasion from dinosaurs, turtles, and crocodilians are clustered together in a channelized sandstone unit. The mismatched taphonomic signatures of the bonebed suggest that it is amixed assemblage, containing bones with different taphonomic histories that were washed together by a flood event. Sedimentological data,includingthe presence of large mud clasts in the bonebed,agree well with this hypothesis. The abundant breakage of the bones in the Rose Quarry bonebed is attributed mainly to trampling. This study …

An Avian Botulism Epizootic Affecting A Nesting Site Population Of Presbyornis : On A Carbonate Mudflat Shoreline Of Eocene Fossil Lake, V. Leroy Leggitt

Loma Linda University Electronic Theses, Dissertations & Projects

The shorebird-duck mosaic bird, Presbyornis, is best known from the Eocene Green River Formation where it often occurs in local monospecific bonebeds, suggestive of mass mortality events. The sedimentology, paleontology, taphonomy, XRD mineralogy, and the carbonate stable isotope signature (δ¹⁸O) of one of these bonebeds was studied on the southern margin of Eocene Fossil Lake.

A series of 408 standardized radiographs were used to construct the first large scale radiograph aided taphonomic map of a vertebrate fossil quarry (3,874 bones were recorded in 11.5 m²). A small group of 100 bones (including a complete skull …

Late Pleistocene Sciurids From Kokoweef Cave, H. Thomas Goodwin

Loma Linda University Electronic Theses, Dissertations & Projects

Three local (Tamias panamintinus, Ammospermophilus leucurus and Spermophilus variegatus) and five extralocal (Tamias minimus, Tamias palmeri, Marmota flaviventris, Spermophilus townsendii, and Spermophilus lateralis) sciurid species (Sciuridae) were identified from the late Pleistocene-early Holocene Kokoweef Cave paleofauna. This fauna was the first documentation of T. minimus, T. palmeri and S. townsendii from the Pleistocene of the Mohave Desert. The 30-ft sedimentary sequence apparently recorded the mid-to late-Wisconsian introduction of S. lateralis into the Kokweef fauna but otherwise documented general taxonomic stability. The ecological diversity of the fauna was consistent with--but did not require--the hypothesis of more equable late Pleistocene climates, and …

Late Tertiary Rodents From The Catamarca Province, Argentina : The Field Museum Collections, Lee A. Schremp

Loma Linda University Electronic Theses, Dissertations & Projects

The rodents collected in the 1920's by the Marshall Field Expedition for the Field Museum of Natural History, Chicago, are systematically reviewed and placed within the stratigraphic framework established at the time of collection. One new genus (Proeuryzygomys) and three new species (Abracoma intermedias, Proeuryzygomys diminutiva, and Cayiodon (Lelongia) catamarcensis) are proposed. Two distinct faunas are recognized corresponding to the Huayquerian and Montehermosan Land Mammal Ages respectively. Several computer programs were developed to aid in character analysis.

Depositional Environments Of The Miocene Esmeralda Formation, Stewart Basin, Stewart Valley, Nevada, Kevin E. Nick

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine specific depositional environments of the Miocene Esmeralda Formation in Stewart Basin (Stewart Valley), Mineral County, Nevada. Previous workers have concentrated on paleontological aspects of the basin and have described in detail the molluscs, mammals and macroflora. Less work has been done on the diatoms and spores and none on the fish, algae, wood or ostracodes. Recently, seven lithostratigraphics units of the Esmeralda Formation have been mapped in Stewart Valley (Clausen, 1983).

Detailed lithofacies are described in each of the seven lithostratigraphic units. Lithofacies 1 is composed of porcelanite and diatomite containing plant …