ASU Electronic Theses and Dissertations
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It has been hypothesized that the ~25 km Rochechouart-Chassenon impact structure (RCIS) in the NW Massif Central, France, was formed during a Late Triassic (ca. 214 Ma) terrestrial impact event that produced a catena of several large craters. Testing this hypothesis, and assessing its possible impacts on biological evolution, requires both accurate and precise dating of candidate impact structures. Like many of these structures, the age of the RCIS is controversial because geochronological datasets yield contradictory results, even when a single isotopic system is used; for example, the two most recent 40Ar/39Ar studies of RCIS yielded statistically inconsistent dates of …
- Horne, Audrey, Hodges, Kip V., van Soest, Matthijs, et al.
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East African extensional basins have played a crucial role in revealing the evolution and characteristics of the early stages of continental rifting and for providing the geological context of hominin evolution and innovation. The numerous volcanic eruptions, rapid sedimentation and burial, and subsequent exposure through faulting and erosion, provide excellent conditions for the preservation of tectonic history, paleoenvironment data, and vertebrate fossils. The reconstruction of depositional environments and provision of geochronologic frameworks for hominin sites have been largely provided by geologic investigations in conjunction with paleontological studies, like the Ledi-Geraru Research Project (LGRP). High-resolution paleoclimate records that can be directly …
- Garello, Dominique Ines, Arrowsmith, Ramon, Campisano, Chris J, et al.
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