AMMONOIDS AND THE TRIASSIC/JURASSIC BOUNDARY IN THE HIMALAYAS OF SOUTHERN TIBET
AMMONOIDS AND THE TRIASSIC/JURASSIC BOUNDARY IN THE HIMALAYAS OF SOUTHERN TIBET
复制标题
DOI：
10.1111/j.1475-4983.2007.00648.x
复制
发表时间：
2007-05
期刊：
影响因子：
2.6
通讯作者：
Jiarun Yin;Paul L. Smith;J. Pálfy;R. Énay
中科院分区：
文献类型：
--
作者：
Jiarun Yin;Paul L. Smith;J. Pálfy;R. Énay
摘要：西藏南部聂拉木地区的格米格剖面提供了含菊石、三叠系上部和侏罗纪基底地层的连续出露。描述了18个种（其中3个新种），并附有插图：Choristoceras marshi Hauer，C. aff。marshi，C.参见nobile Mojsisovics，C.尼亚拉芒斯新种（nyalamense sp. nov.）germigense Eopsiloceras sp. nov.，侧棘藻biformis（Sowerby）、Rhacophyllites sp.、Nevadaphyllites cf. psilomorphus（Neumayr），Neophyllites sp. indet.，Neophyllites cf biptychus（Lange）、西藏裸角石Psiloceras tibeticum sp. nov.、P. calliphyllum（Neumayr），Euphyllites cf. struckmanni（Neumayr），盾叶甲，Alsatites spp.，Kammerkarites frigga和K.菊石动物群显示出强烈的亲和力，北方石灰质阿尔卑斯山，虽然在Calliphyllum区的多样性明显较低。三叠纪/侏罗纪界线的菊石序列可划分为四个带：雷田期的Marshi带、海塘期的Basal Tibeticum带、海塘期的下Calliphyllum带和海塘期的中Pleuronotum带。它是特提斯域中唯一已知的跨越三叠纪/侏罗纪边界的未浓缩的层序。Marshi和Calliphyllum带与北方石灰质阿尔卑斯山的相同带相关。西藏带是一个新的局部带，它是马尔什带和丽蝇带之间的过渡带，既有离角兽，也有裸角兽。它的基底被认为是东特提斯侏罗纪的基底。
Abstract: The sections of Germig in the Nyalam area, southern Tibet, provide a continuous exposure of ammonoid‐bearing, uppermost Triassic and basal Jurassic strata. Eighteen species (three of them new) are described and illustrated: Choristoceras marshi Hauer, C. aff. marshi, C. cf. nobile Mojsisovics, C. nyalamense sp. nov., Eopsiloceras germigense sp. nov., Pleuroacanthites aff. biformis (Sowerby), Rhacophyllites sp., Nevadaphyllites cf. psilomorphus (Neumayr), Neophyllites sp. indet., Neophyllites cf. biptychus (Lange), Psiloceras tibeticum sp. nov., P. calliphyllum (Neumayr), Euphyllites cf. struckmanni (Neumayr), Discamphiceras pleuronotum (Canavari), Alsatites spp., Kammerkarites frigga, and K. sp. The ammonoid fauna shows a strong affinity to that of the Northern Calcareous Alps, although diversity in the Calliphyllum Zone is markedly lower. The ammonoid succession across the Triassic/Jurassic boundary is subdivided into four zones: the Rhaetian Marshi, the basal Hettangian Tibeticum, the lower Hettangian Calliphyllum, and the middle Hettangian Pleuronotum zones. It is the only known succession across the Triassic/Jurassic boundary in the Tethyan Realm that is not condensed. The Marshi and Calliphyllum zones are correlated with the same zones in the Northern Calcareous Alps. The Tibeticum Zone, a new local zone, is transitional between the Marshi and the Calliphyllum zones in that it yields both choristoceratids and psiloceratids. Its base is taken to mark the base of the Jurassic System in the eastern Tethys.