US-South Africa Cooperative Research: Event Stratigraphy across the Permo-Triassic Boundary in the Karoo Basin

该奖项支持华盛顿大学地质科学系Peter Ward和南非开普敦南非博物馆Roger Smith之间的合作研究项目。 该项目名为“卡鲁盆地二叠纪-三叠纪边界的事件地层学”，将研究南非2.5亿年前二叠纪-三叠纪边界的大型脊椎动物灭绝和稳定同位素组成变化的记录。 新的生物地层学，化学地层学和磁性地层学的结果从两个陆地二叠纪-三叠纪边界网站（Bethulie和Lootsberg通行证）产生新的洞察力的克里思和严重程度的大规模灭绝结束二叠纪在南非卡鲁地区。 南非地质调查局（Geological Survey of South Africa）先前的工作表明，卡鲁地区陆生脊椎动物的大规模灭绝是灾难性的，超过三分之二的物种在二叠纪顶部消失。 灭绝事件的持续时间可以通过校准在二叠纪卡鲁盆地积累20米河流沉积物所需的时间来估计。 这可能是超过10，000和不到100，000年。 二叠纪/三叠纪大灭绝事件的一个可能原因是短暂的热脉冲，可能是由海洋翻转引起的二氧化碳流入大气，再加上西伯利亚陷阱的排放。 拟议中的美国-南非合作研究将通过产生大量新的化石材料和一套用于同位素分析的碳酸盐样品来完善这些估计。 新的化石信息将使人们能够更精确地估计这一地区的灭绝速度。 该项目由国际方案司和地球科学司联合支助。

This award supports a cooperative research project between Peter Ward, Department of Geological Sciences, University of Washington, and Roger Smith, South African Museum, Cape Town, South Africa. The project, which is entitled "Event Stratigraphy across the Permo-Triassic Boundary in the Karoo Basin," will examine the record of large vertebrate animal extinctions and changes in stable isotope composition across the 250 million year old Permian-Triassic boundary in South Africa. New biostratigraphic, chemostratigraphic, and magnetostratigraphic results obtained from two terrestrial Permo-Triassic boundary sites (Bethulie and Lootsberg Pass) yield new insight into the tempo and severity of the mass extinction ending the Permian Period in the Karoo region of South Africa. Previous work by the Geological Survey of South Africa has demonstrated that the mass extinction among terrestrial vertebrates was catastrophic in the Karoo, with over two-thirds of all species disappearing at the top of the Permian. The duration of the extinction event can be estimated by calibrating the time necessary to accumulate 20m of fluvial sediments in the Permian Karoo basin. This probably is more than 10,000 and less than 100,000 years. A suggested cause of the Permo/Triassic mass extinction event was a short-lived heat pulse, probably produced by a flux of carbon dioxide into the atmosphere caused by oceanic overturn, combined with emissions from the Siberian Traps. The proposed US-South African collaborative research will refine these estimates by producing a wealth of new fossil material and a suite of carbonate samples to be used for isotopic analysis. The new fossil information will allow a much more precise estimate of the rates of extinction in this region. The project is supported jointly by the Division of International Programs and the Division of Earth Sciences.