Author

Kaylyn Oates

Publication Date

2012

Document Type

Honors Thesis

Department

Geosciences

Keywords

Glacial landforms-Death Valley (Calif. and Nev.), Sedimentology, Paleobiology, Fossils, Snowball Earth (Geology), Death Valley, Neoproterozoic, Microfossils, Cap carbonate

Abstract

During the late Neoproterozoic era (Cryogenian, 840–635 Ma), there is evidence for low latitude glaciations capped by enigmatic carbonate deposits, which imply the entire earth at that time was entombed in ice. This phenomenon is known as Snowball Earth. Death Valley, CA contains Neoproterozoic including glacial deposits and carbonate rocks. Neoproterozoic, however correlating these deposits globally has proved challenging. In eastern Death Valley, the provenance of the Virgin Springs Limestone, located within the Kingston Peak Formation, as a possible cap carbonate has been uncertain. In this study, the sedimentological and paleobiological observations of the Virgin Springs Limestone combined with the geochemical and field-mapping data allow for the placement of this otherwise enigmatic unit within the greater Death Valley stratigraphy. We report discovery of vase shaped microfossils (VSMs) here. The presence of these forms is consistent with geochemical and geological relationships that suggest that the Virgin Springs Limestone was deposited before the Sturtian glaciation episode of Snowball Earth. Correlations suggest these VSMs formed between 742 and 717Ma, filling a gap in the fossil record.

Language

English

Comments

iv, 42 p. : ill. (some col.) Honors project-Smith College, Northampton, Mass., 2012. Includes bibliographical references (p. 40-42)

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