东喜马拉雅地区晚三叠世—早侏罗世的菊石类

Late Triassic and Early Jurassic Ammonoids from Eastern Himalayas

在东喜马拉雅范围以内的西藏康马、洛扎和隆子地区有国内首次发现的晚三叠世诺利期—早侏罗世Glyphidites、Phormedites、Epideroceras、Phricodoceras Uptonia等菊石。晚三叠世诺利期有Tibetites sp.、Anatibetites sp.、Glyphidites sp.、Cyrtopleurites sp.、Parajuvavites sp.、Sagenites sp.和Phormedites sp.。早侏罗世辛涅缪尔期有Arnioceras ceratoides、Angulaticeras sp.、Arnioceras sp.、Juraphyllites sp.、Epideroceras sp.以及普林斯巴赫期Phricodoceras cf.cornutum、Uptonia sp.、Galaticeras sp.、Gleviceras cf.paniceum等。东喜马拉雅地区的菊石动物群在晚三叠世—早侏罗世期间的幕式出现与海侵和沉积环境变深有关,代表受海平面变化控制的晚三叠世的诺利中期(Columbianus带)、早侏罗世的辛涅缪尔期(Semico-statum带)、以及普里斯巴赫早期(Jamestoni带)的全球性菊石动物群扩散和迁移。

Late Triassic and Lower Jurassic ammonoids were newly collected from Kongma, Lhozag and Lonzi, eastern Himalayas, including Tibetites sp. , Anatibetites sp. , Glyphidites sp. , Cyrtopleurites sp. , Parajuvavites sp. , Sagenites sp. , Phormedites sp. （Middle Norian） , Arnioceras ceratoides, Angulaticeras sp. , Arnioceras sp. , Juraphyllites sp. , Epideroceras sp. （Sinemurian） , and Phricodoceras cf. cornutum, Uptonia sp. , Galaticeras sp. , Gleviceras cf. paniceum （Pliensbachian）. Glyphidites, Phormedites, Epideroceras, Phricodoceras and Uptonia are known in China for the first time. The ammonoid assemblages stratigraphically exhibit an episodic appearance, or a discontinuous sequence, dating the Columbianus, Semicostatum and Jamestoni Zones; the faunal migration or dispersal are referred to as global bio-events, forced by sea-level changes.