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Abstract: Using Carbon Isotope Stratigraphy on Basin-Scale Problems: An Example from the Neoproterozoic-Cambrian "Grand Cycles" of eastern California


The nature of the carbonate half cycle in the formation of so called "grand cycles" has recently been debated for the Cambrian sections in the White-Inyo/Death Valley region of eastern California. In an attempt to clarify the nature of the carbonate half cycle, carbon isotopic data was collected from the Neoproterozoic-Cambrian Wood Canyon Formation (Death Valley) and the equivalent Deep Spring Formation (White-Inyo region) along an onshore-offshore transect. The chemostratigraphic sections were compared to the global {13}C reference curve for the Neoproterozoic-Cambrian interval. The data demonstrate that the middle sections are older (in a relative sense) than either the near-shore or off-shore sections. This suggests that the carbonate cycle of these grand cycles nucleated in mid-shelf areas and spread both seaward and landward through time, a conclusion that differs from the original grand cycle models, as well as more recent models (as based on limited trilobite biostratigraphy). Thus, it may be possible to use chemostratigraphy to solve basin-scale stratigraphic problems as well as global correlation issues.

Search and Discovery Article #90945©1997 AAPG Pacific Section Meeting, Bakersfield, California