东昆仑阿尔格山二叠纪生物礁的特征及其古地理古气候的意义

Characteristics of the Permian reefs in Aergeshan,eastern Kunlun Mountains and their palaeogeographic and palaeoclimatic significance

东昆仑山脉西段二叠纪生物礁由早二叠世、中二叠世的栖霞期和茅口期三个层位组成 ,早二叠世的礁和中二叠世栖霞期的礁是我国首次发现的 ,填补了我国二叠纪礁的空白。早二叠世礁的时代相当于阿赛尔-萨克马尔 -阿丁斯克期 ,主要表现为海绵礁、苔藓虫礁和Shamovella (Tubiphytes) -古石孔藻礁。但缺失由Palaeoaplysina组成的礁。中二叠世栖霞期的礁表现为海绵 -苔藓虫礁、Shamovella -苔藓虫礁和叶状藻礁。中二叠世茅口期的礁与栖霞期的礁类型基本一致。阿尔格山礁是塔吉克斯坦 -喀拉昆仑地体的一个部分 ,该地体位于南纬 30°以北的东特提斯海内。此处的二叠纪礁由各种生物组成 ,包括珊瑚海绵、苔藓虫、Shamovella、古石孔藻、棘皮类、有孔虫、叶状藻、粗枝藻以及腹足类等 ,推测该礁形成于温暖和炎热气候条件下的暖水内 。

The huge and spectacular Permian reefs exposed in eastern Kunlun Mountains occur in three stratigraphic horizons They are the Lower Permian or Asselian Sakmarian Artinskian Stages,the Qixia Stage and Maokou Stage of Middle Permian,in which,the Lower Permian reefs and Middle Permian Qixia reefs are the first discoveries of Permian reefs in China,although some microbial reefs of Lower Permian were discovered in southern Qinling Mountains The Lower Permian reefs consist of three types of reefs: sponge reefs,bryozoan reefs and Shamovella Archaeolithoporella cement reefs The reefs in the Qixia Stage of Middle Permian are also composed of three types: sponge bryozoan reefs, Shamovella bryozoan reefs and phylloid algal reefs The reefs in the Maokou Stage of Middle Permian are generally the same as those of Qixia reefs The Permian reefs in the Aergeshan are regarded as a component part in Tadzhikistan Karakoram Terrane which was situated paleo latitudinally to the north of 30°S in the eastern Tethys The Permian reefs here are composed of various kinds of organisms,including coralline sponges,bryozoans, Shamovella,Archaeolithoporella ,phylloid and dasycladacean algae,echinoderms,foraminifers and gastropods,but no Palaeoaplysina Thus we could infer that these reefs were formed in warm seawater under temperate and tropical climate,rather than in cool water