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描述双壳类化石 42种 ,建立 1 0新种 :Grammatodon (Nanonavis)minumsp .nov.,Propeamussium(P .)tibetensesp.nov.,Plicatulahimalayensissp.nov.,Pseudolimeaduodecicostatasp .nov.,Pycnodonte (Phygraea)gambaensissp.nov.,Nototrigonia (N .)himalayensissp.nov.,Linearia (L .) gieumalensissp.nov.,Icanotiaxizan gensissp.nov.,Panopeaxizangensissp.nov.,Cuspidariatibiticasp.nov.。它们均产自西藏南部岗巴地区的岗巴群。其中大部分标本产自岗巴群的下中部 ,时代为Aptian至Albian期 ,少量产自岗巴群上部 ,时代大致为Cenomanian至Coniacian期。Aptian—Albian期双壳类有地区性属Astartoides和Yoldioides以及众多地区性种 (约占 6 1 % ) ,标志着一个地区性中心的存在。同时 ,它们又表现出与澳大利亚Aptian—Albian动物群有密切的联系 ,澳大利亚特有的属Eyrena,Maccoyella,Nototrigonia和特有的种 (约占 2 9% )在岗巴群下中部被找到 ,都是在北半球的首次记录。这个动物群与雅鲁藏布江缝合带以北同时期的动物群差别很明显 ,后者与东亚、西亚和欧洲的双壳类有密切的联系。这些事实说明 ,在Aptian—Albian时期 ,印度次大陆已经开始向北漂移 ,但漂移的距离还不远 ,位于印度次大陆北部边缘浅海的岗巴?
42 species of bivalve fossils were described and 10 new species were established: Grammatodon (Nanonavis) minumsp. Nov., Propeamussium (P.) Tibetensesp. Nov., Plicatulahimalayensissp. Nov., Pseudolimeaduodecicostatasp. Nov., Pycnodonte (Phygraea) gambaensissp.nov ., Nototrigonia (N.) Himalayensissp. Nov., Linearia (L.) gieumalensissp.nov., Icanotiaxizan gensissp.nov., Panopeaxizangensissp. Nov., Cuspidariatibiticasp. They are all produced from Gamba in the Gamba area in southern Tibet. Most of the specimens were from the lower middle part of Gamba Group, from the Aptian to Albian times, from the upper part of Gamba Group and from Cenomanian to Coniacian times. The Aptian-Albian period bivalves, Astartoides and Yoldiides, and numerous endemic species (about 61%) indicate the existence of a regional center. At the same time, they are also shown to be closely associated with the Australian Aptian-Albian fauna. The endemic genera Eyrena, Maccoyella, Nototrigonia and endemic species (29%) of Australia are found in the lower middle part of Gamba, both in the northern hemisphere The first record. This fauna is distinct from the fauna north of the Brahmaputra suture zone of the same period, which is closely linked to the bivalves in East Asia, West Asia and Europe. These facts show that during the Aptian-Albian period, the Indian subcontinent has begun to drift northward, but it is not far away. Is it located in the shallow sea on the northern edge of the Indian subcontinent?