AMMONOIDS AND THE TRIASSIC/JURASSIC BOUNDARY IN THE HIMALAYAS OF SOUTHERN TIBET

  1. JIARUN YIN1,
  2. PAUL L. SMITH2,
  3. JÓZSEF PÁLFY3,
  4. RAYMOND ENAY4

Article first published online: 17 MAY 2007

DOI: 10.1111/j.1475-4983.2007.00648.x

Issue

Palaeontology

Palaeontology

Volume 50, Issue 3, pages 711–737, May 2007

Additional Information

How to Cite

YIN, J., SMITH, P. L., PÁLFY, J. and ENAY, R. (2007), AMMONOIDS AND THE TRIASSIC/JURASSIC BOUNDARY IN THE HIMALAYAS OF SOUTHERN TIBET. Palaeontology, 50: 711–737. doi: 10.1111/j.1475-4983.2007.00648.x

Author Information

  1. 1

    China University of Geosciences, 29 Xueyuan Lu, Beijing 100083, China; e-mail: yjr@cugb.edu.cn

  2. 2

    Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC, V6T 1Z4, Canada; e-mail: psmith@eos.ubc.ca

  3. 3

    Research Group for Palaeontology, Hungarian Academy of Sciences, Hungarian National Museum, POB 137, Budapest, H-1431 Hungary; e-mail: palfy@nhmus.hu

  4. 4

    Université Claude-Bernand Lyon 1, UFR des Sciences de la Terre, Boulevard du 11 November 1918, 69622 Villeurbanne Cedex, France 43; e-mail: raymond.enay@univ-lyon1.fr

Publication History

  1. Issue published online: 17 MAY 2007
  2. Article first published online: 17 MAY 2007
  3. Typescript received 2 September 2005; accepted in revised form 6 July 2006

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Keywords:

  • Triassic/Jurassic boundary;
  • eastern Tethys Ocean;
  • Tibetan Himalayas;
  • ammonoids;
  • biostratigraphy

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.

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