摘要
在拉萨以东约１００ ｋｍ 处的下波郎和得中等地， 广泛出露着以火山岩系沉积为主体的叶巴组， 新近从中发现了大量的双壳类化石， 以Ｋｏｂａｙａｓｈｉｔｅｓ ｈｅｍｉｃｙｌｉｎｄｒｉｃｕｓ Ｈａｙａｍｉ， Ｐｒｏｐｅａｍｕｓｓｉｕｍ （ Ｐｒｏｐｅａｍｕｓｓｉｕｍ） ｌａｅｖｉｒａｄｉａｔｕｍ （ Ｗａａｇｅｎ） ， Ｐｒｏｎｏｅｌｌａ ｐｉｎｄｉｒｏｅｎｓｉｓ Ｃｏｘ 和Ｃｏｒｂｉｃｅｌｌｏｐｓｉｓｌａｅｖｉｓ （Ｓｏｗｅｒｂｙ） 为代表， 共计１９ 属２０ 种。双壳类动物群古生物地理面貌同北侧羌塘—印支地块早—中侏罗世双壳类动物群以及欧洲和日本同期双壳类动物群有极大的相似性， 在某种程度上又具有东亚区、欧洲区以及埃塞俄比亚区的某些特征属， 在一定程度上显示出不同生物地理区动物群的混生面貌。从生物地理区系的角度来看， 班公湖—怒江缝合带虽然有可能是侏罗纪一度出现的洋盆， 但其张开的幅度和持续的时间不足以导致其南。
The fossil materials in this paper were collected from the Yeba Formation outcropping over the Dezhong\|Xiabolang area, about 100km east of Lhasa, Tibet. Twenty bivalve species of 19 genera are recognized. Few fossil was found from the volcanic rocks in this area before, and most of bivalve fossils are reported by the author for the first time, such as Kobayashites hemicylindricus Hayami, Propeamussium(Propeamussium)laeviradiatum (Waagen), Pronoella pindiroensis Cox and Corbicellopsis laevis (Sowerby),etc.The bivalve fauna of the Lhasa area exhibits an affinity to the Middle Jurassic faunas of Qiangtang area(including north Tibet, south Qinghai, west Yunan, Burma, and Vietnam), East Tethys(Japan), and west Tethys(Europe),also contains a few elements of the Ethiopian province. It indicates somewhat transitional distinction between these biogeographic provinces. Judging from the bivalve\|paleobiogeographic viewpoints, the width of the so\|called Bangong\|Nujiang Ocean seems not to have played a significant barrier\|role in both oceanal scale and duration for faunal exchange between the Lhasa and Qiangtang blocks.\;
出处
《现代地质》
CAS
CSCD
北大核心
1999年第3期291-297,T001,共8页
Geoscience
基金
国家自然科学基金
关键词
拉萨地块
早-中侏罗世
双壳类
古生物地理
the Lhasa Block, Early and Middle Jurassic, bivalve, paleogeography
