--> Abstract: New Sedimentological Investigations in Triassic Strata of Peary Land on North Greenland: Scope of Study, Preliminary Results and Palaeogeographic Significance for the Southwestern Margin of the Barents Shelf, by Hans-Ivar Sjulstad; #90177 (2013)

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New Sedimentological Investigations in Triassic Strata of Peary Land on North Greenland: Scope of Study, Preliminary Results and Palaeogeographic Significance for the Southwestern Margin of the Barents Shelf

Hans-Ivar Sjulstad

The NPD is currently carrying out a palaeogeography project meant to focus specifically on the southwestern margin of the Barents Sea and its geo-historic link to sedimentary basins and tectonics of North Greenland. Plate Tectonic reconstructions indicate a very tight pre-spreading link between the Wandel Sea Basin and the southwestern margin of the Barents Shelf. The Post-Caledonian/Post-Ellesmerian sedimentary succession of the Wandel Sea Basin bears significant resemblance to its stratigraphic counterparts in the western Barents Sea and the Archipelago of Svalbard, and the two regions were probably parts of the same depositional systems during certain episodes of the geological past. Careful and detailed sedimentological studies of sedimentary strata of the Wandel Sea Basin is therefore considered to be vital in the process of improving the understanding of the geological history of the western margin of the Barents Shelf. In the light of these acknowledgements the NPD is taking part in GEUS` 2012-2014 geological field campaign to North Greenland .The Wandel Sea Basin comprises strata ranging in age from Visean to Paleogene. During the first field season during summer 2012, the NPD elected to work at the northernmost peninsula of Peary Land, paying specific attention towards the Late Permian Midnatfjeld Formation, the two Triassic formations Parish Bjerg and Dunken, and the Late Cretaceous Herlufsholm Strand Formation. Sedimentological descriptions and field logging with special emphasis on ichnology and sedimentary structures were carried out. The formations were sampled for thin sections, micropalaeontology and provenance. This communication is limited to deal with the Triassic formations, and presents preliminary results and suggestions regarding reinterpretations of depositional environments. The Triassic Parish Bjerg Formation and Dunken Formation, have in the past been broadly interpreted as shallow marine in origin. Findings from this study suggests that there are basis for more specific designations regarding depositional environments. For the investigated part of the Parish Bjerg Formation, a slight upward shallowing system from storm and wave dominated lower shoreface environments towards tidally influenced marginal marine and delta front environments are suggested. For the Dunken formation, a somewhat more distinct shallowing upward trend is recognized. This formation displays sub-tidal heterolithics at the base, but shallows rapidly upwards into shoreface-dominated strata. The cycle is topped by fluvio-deltaic facies associations. This mega-cycle apparently ends near the top of the type-section where an abrupt transgression is apparent. Palaeo-flow measurements in investigated strata suggest predominant sediment transport directions towards the east, south and north. Hence, the investigated Triassic sedimentary systems of Peary Land may have influenced the rock record of the southwestern margin of the Barents Shelf.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013