A Revised Pre-break up fit of NO and Greenland: Implications for Regional Correlations, Paleostress and the COB Puzzle

Ebbe Hartz

Traditional plate reconstructions of the Northeast Atlantic advocate relatively orthogonal drift. In contrast, we present a new reconstruction fitting microcontinents and major plates in the North Atlantic applying particular focus to the Northwards drift of Greenland during the Late Mesozoic-Early Cenozoic. This new reconstruction has several implications: Firstly, displacing Greenland to the south (backwards in time) clarifies gaps and overlaps of the continent-ocean boundary (COB) between NO and Greenland. This solves long standing enigmas by specifically providing room for Hovgård, and East Greenland Ridge along the west Barents Margin, and furthermore provides space for a much expanded continental plate of the Jan Mayen microcontinent extending from North of the Jan Mayen Island and to SE Iceland. Secondly, we show that the displacement vectors of the Cretaceous opening of the Arctic Ocean, and the Late Mesozoic to Mid Cenozoic opening between Greenland and North America are almost 90 degrees from the displacement vectors of the Cenozoic of the NO-Greenland Sea. This implies a near reversal of faults so that old strike slip faults are reactivated as normal faults and visa versa. The microcontinents of the region appear cut off their greater plate by a combination of extension and shear that directly correlate to the predictions of our small circle models. Furthermore, the new model explains transpressional and transtensional features observed both on land East Greenland, and on the continental shelfs. Thirdly, we test the effect of sheared versus extended break up in 3D thermal models and suggest that a sheared margin is substantially more heated than an extended due to the intense effect of the passing mid oceanic ridge. This influences the evaluation of Norwegian frontier areas including the Lofoten-Vesterålen (extended) margin, versus the sheared margin of the western Barents Sea. The double break up of microcontinents, also calls for dedicated studies of thermal maturation, given that hot oceanic rocks once bordered these narrow slivers of continent. In short, our results suggest that within the outer 50 km of a continent, the thermal history is significantly affected by the break up process.

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