The Henson Gletscher Formation, North Greenland, and its bearing on the global Cambrian Series 2–Series 3 boundary

 

Authors: Geyer G, Peel JS

Published in: Bulletin of Geosciences, volume 86, issue 3; pages: 465 - 534; Received 30 December 2010; Accepted in revised form 2 September 2011; Online 23 September 2011

Keywords: Lower–Middle Cambrian boundary, trilobite biostratigraphy, global correlation, GSSP, Henson Gletscher Formation, Greenland,

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Abstract

The Henson Gletscher Formation of North Greenland yields moderately diverse trilobite faunas which bracket the Cambrian Series 2–Series 3 boundary interval. A number of the trilobite taxa permit correlation into other parts of Laurentia and to other Cambrian continents, thus enhancing correlation within this stratigraphical interval of the traditional Lower–Middle Cambrian boundary. In particular, the occurrence of Ovatoryctocara granulata and O. yaxiensis substantially improves the intercontinental recognition of the O. granulata level, a prime GSSP candidate. In contrast, the level with Oryctocephalus indicus cannot be located in a number of Cambrian continents with sufficient precision, making this level unsuitable for the definition of a GSSP for the base of the Cambrian Series 3 and Stage 5. Further support for the correlation potential of the base of the range of Ovatoryctocara granulata comes from recent carbon isotope studies that indicate a striking negative excursion in sections of South China (ROECE event) that probably coincides with similar excursions in Laurentia. Four new trilobite species are described: Zacanthopsis blakeri sp. nov., Protoryctocephalus arcticus sp. nov., Eoptychoparia pearylandica sp. nov. and Onchocephalus? freucheni sp. nov.

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