二叠纪Guadalupian与Lopingian之交菊石类的绝灭高峰

EXTINCT SUMMIT OF AMMONOIDS NEAR THE BOUNDARY BETWEEN GUADALUPIAN AND LOPINGIAN OF PERMIAN

除P/T界线间菊石类几乎全部绝灭之外,在二叠纪Guadalupian世Capitanian期与Loingian世Wuchiapingian期之间,存在着另一次菊石类的全球性大规模选择性绝灭高峰.即菊石类由Guadalupian世Roadian—Capitanian期(茅口期)的高度繁盛阶段,历经高速率、大规模选择性灭绝,迅速进入Lopingian世Wuchiapingian期的衰退阶段,继而发生了二叠纪末的P/T之交菊石类绝灭高峰.因而,Guadalupian世Capitanian期与Lopingian世Wuchiapingian期之交菊石类绝灭事件,可视为P/T界线间更强烈的绝灭事件的预兆.这一事件可能与全球性构造运动、海平面下降和火山活动等地内地质事件有关.

Besides the Permian-Triassic extinction there was another world-wide massive extinction summit of Ammonoids at the boundary between the Capitanian of the Guadalupian Epoch and the Wuchiapingian of the Lopingian Epoch in Permian. Cross the aforesaid boundary, Ammonoids fastly changed from the flourishing stage during the Roadian-Capitanian(Maokouan) into the decline stage during the Wuchiapingian after a rapid(more than 1 families/Ma and 6 genera/Ma) and large -scale(more than 10 families and 60 genera)extinction.The alternative mass extinctive event at the boundary between the Capitanian and the Wuchiapingian, which was probably related with some geological events, such as global tectonic movement,lowering of sea level and volcanic activity etc., consequently can be regarded as an omen of the severe mass extinctive event at the Permian-Triassic boundary.In order to compare the extinction of Ammonoids at the boundary between Capitanian of Guadalupian Epoch and Wuchiapingian of Lopingian Epoch with the extinction at Permian-Triassic boundary, four time intervals are adopted as follows:1. Artinskian-Kubergandian(roughly e-qual to Chihsian), 2. Roadian-Capitanian( roughly equal to Maokouan), 3. Wuchiapingian( roughly equal to Dzhulfian) and 4. Changhsingian(roughly equal to Dorashamian), as basic statistical u-nit to depict the rise and fall of the Permian Ammonoids. Using a certain time interval as statistic unit to depict the rise and fall of the Permian Ammonoids. Using a certain time interval as statistic unit for concerned data is universally adopted by many geologists.