| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | July 21, 2016 |
| Latest Amendment Date: | July 21, 2016 |
| Award Number: | 1624302 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Dena Smith-Nufio
dmsmith@nsf.gov (703)292-7431 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2016 |
| End Date: | August 31, 2020 (Estimated) |
| Total Intended Award Amount: | $190,345.00 |
| Total Awarded Amount to Date: | $190,345.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
4120 MAYFLOWER HILL WATERVILLE ME US 04901-8841 (207)859-4342 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
ME US 04901-5807 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
Sedimentary Geo & Paleobiology, SURFACE EARTH PROCESS SECTION |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Earth's biosphere experienced its greatest mass extinction ~251.9 million years ago at the end of the Permian Age. In approximately 60,000 years, the oceans experienced a loss of 90% of marine life. Many workers believe that a similar change co-occurred on land, but rock-and-fossil records from the continents are not well dated. For more than a century, the Karoo Basin, South Africa, has served as the center for interpreting the response of terrestrial ecosystems to this crisis. The current proposal uses a multidisciplinary, international team of geoscientists to refine the physical and chemical conditions around which the biological event is believed to have occurred in this basin. Field-and-laboratory training of undergraduate STEM students continues to be an integral component of the project, educating the next generation of geoscientists in an understanding of Earth Systems in deep time.
Mechanisms responsible for the end-Permian biodiversity loss are attributed to changes in atmospheric and oceanic chemistries. These were a consequence of the emplacement of basalt in a large igneous province, the Siberian Traps. Increasing atmospheric gas concentrations, accompanied by increasing global temperatures, stressed the physiological limits of the plants and animals. It is essential to know if these stresses affected both marine and terrestrial ecosystems, concurrently, or if their responses are temporally out of phase. This project will use stratigraphy, sedimentology, magnetic rock properties, and whole-rock and stable-isotope geochemistry to look at the physical and chemical conditions, in addition to paleontology and palynology to determine the biological components, and constrain these in time (employing high resolution geochronology). An empirical model will be developed to assess the stratigraphic applicability of paleobiological data, leading to a better interpretation of the latest Permian to earliest Triassic terrestrial transition.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Nearly 252 million years ago, Earth experienced the most severe biodiversity crisis in our history. This crisis is known as the end-Permian extinction event where nearly 90% of marine organisms ceased to exist over a geologically short interval of time, estimated between 40,000 and 60,000 years. Scientific consensus about the cause of the extinction focuses on increasing concentrations of carbon dioxide, methane, sulfur dioxide, and other atmospheric gasses resulting for the long-term volcanic activity associated with the Large Igneous Province known as the Siberian Traps. The idea that there was a coincident loss of lfe on land, affecting both plants and animals, has been long held in the scientific community. This idea is based on the fossil record of vertebrates from time-equivalent rocks in the Karoo Basin, South Africa. The Karoo Basin model is widely accepted and used to explain trends in all other continental land masses at that time. Our international, multidisciplinary research group has tested this widely held model, with results that are significantly different. We have demonstrated that:
- there is a decoupled response of terrestrial and marine ecosystems in the latest Permian, based on high precision geochronological dating of volcanic deposits;
- there is no evidence to support the long held idea of a vertebrate-fossil based boundary between the Permian and Triassic-aged rocks in the basin;
- a reverse magnetic polarity chron exists in the section of rock spanning the purported PTB on the Bethel farm, Free State, where the end-Permian extinction model orginated. The end-Permian extinction crisis in the oceans is located in a normal polarity chron;
- the fossil-plant record of pollen and spores from a previously reported post-extinction horizon is that of the pre-extinction vegetation which has been reported to be extinct;
- fossil wood in reportedly post-extinction rocks exhibit a ?complacent? wood anatomy (wood with little annual variationin growth rings, indicating a mild and consistent climate that did not limit growth from year to yea) along with impressions of Glossopteris leaves, both indicative of a wet landscape, where hyper-arid condtions have been proposed;
- the data on which the end-Permian extinction of vertebrates, in all localities, is problematic and both the reported patterns and trends can not be replicated using the original database; that have been used to propose an end-Permian mass extinction event wherein we have identified significant problems with the original database on which the crisis is identified;
- there is no physical or geochemical evidence to support the presence of arid, evaporite (playa) lake deposits in any interval associated with the previously reported extinction event; rather
- paleoclimate estimates of Mean Annual Temperature and Mean Annual Precipitation, based on geochemistry of calcium-rich ancient soils of the latest Permian, indicate a cool (MAT 10? C) and humid (900-1100 mm/yr MAP) climate, which are in contrast to the prevailing model of increasing temperatures and aridity that precedes the reported vertebrate extinction event.
In summary, the current NSF funded project has resulted in the need to reassess the global response to what has been termed the "Mother of Mass Extinction" events, based on multidisciplinary data of high stratigraphic and analytical resolution.
Last Modified: 10/14/2020
Modified by: Robert A Gastaldo
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