| 英文摘要: | RUI, Collaborative Research: A High resolution Paleontological, Ichnological, and Chemostratigraphic Study of Late Devonian Mass Extinctions
by
Diana Boyer, EAR-1348981, SUNY Oswego
Gordon Love, EAR-1348988, Univ. California, Riverside
ABSTRACT
The rock record preserves a detailed history of past events in life history, and understanding these events, particularly episodes of unusual biotic turnover, is of paramount importance, particularly in this time of our current diversity crises. There have been many large scale extinction events throughout geologic history, and despite extensive study, the Late Devonian mass extinction events in the Frasnian-Famennian still remain enigmatic in terms of a causal mechanism. Although numerous kill mechanisms have been proposed, marine anoxia is widely thought to be a major contributing factor, in part because of the pervasiveness of organic-rich black shale. This study will test for extensive anoxic and/or pervasive euxinic (sulfidic water column) conditions associated with several biotic turnover events preserved in a Laurentian basin. PIs will use an integrated paleontological, inorganic geochemical, and lipid biomarker approach performed at high spatial resolution to reconstruct secular changes in ancient microbial and metazoan source organism inputs, and marine redox structure in these ancient epeiric seaways. They will test for a correlation between the magnitude and timing of extinction events and patterns of oxygen and euxinic stress which prevailed.
The utility of combining paleontological and geochemical proxies to recognize bottom water oxygen levels on a fine-scale in black shale facies has been realized (Boyer et al., 2011), but not yet applied to understand the dynamics of major events in the history of life. The new light we are shedding on Late Devonian biospheric and environmental evolution in North America will inform and direct future work in biogeochemistry, paleontology/paleobiology, evolutionary biology, and ocean-atmosphere evolution. Central to this research is a unique bridging of organic and inorganic geochemical methods with paleontology within a broad field-based template to yield high-resolution bio- and chemostratigraphic records that span the Late Devonian mass extinction events and their aftermath. At the heart of this research proposal is the training and education of a group of talented graduate, undergraduate and K-12 school students in the geosciences at UCR and SUNY Oswego, many from underrepresented ethnic groups, through a combination of direct involvement in the research project or through a variety of outreach ventures. |