ABSTRACT

Microplankton biostratigraphic zones are established in the thickest exposed section of the Savik Formation in the Sverdrup Basin. This section is located at Vantage Point, Axel Heiberg Island. The ranges of the following key taxa subdivide a sequence that ranges in age from Toarcian to Volgian: Gonyaulacysta jurassica (M. Call -- ?Top of Jur.); G. jurassica var. longicornis (Oxf.); Acanthaulax spp. (M. Call. -- L. Oxf.); Nannoceratopsis pellucida (M. Bath. -- M. Call.); Paragonyaulacysta calloviense n. gen., n. sp. (L. Call.); Pareodinia tripartitus var. obtusus n. sp., n. var. (M. Bath. -- U. Bath.); P. sp. 2 (U. Baj. -- M. Bath.); Nannoceratopsis gracilis (?Toar. -- U. Baj.). The lateral extent of these zones is demonstrated by correlations between the Vantage Point section and sections located on Bjarnasson Island and on Fosheim Peninsula of Ellesmere Island.

Of the 34 microplankton species used in the zonation 8 are new. The following new taxa are named and described: Gonyaulacysta jurassica var. brevis n. var.; Paragonyaulacysta calloviense n. gen., n. sp.; Pareodinia tripartitus n. sp.; P. tripartitus var. obtusus n. sp., n. var.; P. tripartitus var. rotundus n. sp., n. var. The genus Pareodinia (Deflandre) is emended to include cysts with 3I archeopyles.

Reworked microplankton indicate that the late Middle Jurassic sediments in the centre of the basin were in part derived from earlier Jurassic deposits along the margin.

The level of organic metamorphism in samples from southern and western Axel Heiberg Island indicates that the prospects for liquid hydrocarbons in the pre-Cretaceous rocks of that area are minimal. Better prospects are indicated for rocks at least as old as early Jurassic on western Ellesmere Island.