Carbon Isotope studies of Phanerozoic Mass Extinction Events

点击翻译按钮获取中文摘要

Carbon isotope studies of marine limestones detect shifts in the depositional ratio of organic carbon to carbonate carbon; profiles of 13C are correlative with major mass extinction events and changes in sea level. During the proposed renewal period we will complete characterization of the carbon isotope profile through the Late Paleozoic and the Permian/Triassic boundary. A sequence of two dozen profiles through the Permian/Triassic boundary in classic sections of the Tethys Sea, from the Alps to China, will be completed and published. A core of over 300 m through the Permian/Triassic boundary in a critical section at Gartnerkofel in the Carnic Alps of Austria, taken in September- October, 1986, will be the subject of a cross-disciplinary study by a consortium of 12 specialists. The earlier manifestations of the Late Paleozoic carbon isotope anomaly, previously detected by us and others in the Late Pennsylvanian, will be confirmed by new collections in the western USA. Geophysical and geochemical models for shifts in the carbon cycle, sea level and other geological parameters will be considered in relation to extinction events.