PLATE TECTONIC UNCERTAINTIES IN THE CENTRAL ARCTIC OCEAN AND THEIR IMPLICATIONS FOR PETROLEUM POTENTIAL ON THE RUSSIAN ARCTIC SHELF

SCOTT, Robert A., CASP, Department of Earth Sciences, University of Cambridge, West Building, 181A Huntingdon Road, Cambridge CB3 0DK United Kingdom, [email protected]

As a percentage of the total marine area, the Arctic Ocean has the most extensive continental shelves of any ocean basin (approximately 53% of the total marine area), of which the vast majority lie within Russian territorial waters. These shelves remain underexplored, and vast areas are virtually unknown, particularly east of the New Siberian Islands: the Russian Arctic region therefore constitutes a huge frontier province for hydrocarbon exploration. The preparation of plate reconstructions and palaeogeographic maps is an important element in developing hydrocarbon exploration strategies for frontier areas; however, a major obstacle to this procedure in the Arctic is the controversy that surrounds opening of the Arctic Ocean.

The Arctic Ocean contains two deep-water oceanic basins, the Eurasia and Amerasia basins, separated by the submarine Lomonosov Ridge, a continental fragment that crosses the Arctic Ocean from Canada to Siberia. Spreading in the Eurasia Basin began in Paleocene time when the Lomonosov Ridge was detached from the Barents/Kara shelf, and continues today on the Gakkel Ridge. Opening of the Eurasia Basin is well constrained by the pattern of linear magnetic anomalies in oceanic crust, and corroborated by the excellent fit of the Lomonosov Ridge against the Barents/Kara margin.

The Amerasia Basin is generally considered to be predominantly of Cretaceous age. In contrast to the Eurasia Basin, there is no easily interpretable pattern of magnetic anomalies, and, furthermore, the origins of several component features in the Amerasia Basin are controversial. Unsurprisingly, therefore, the mechanism responsible for opening the Amerasia Basin is disputed. Different spreading mechanisms imply profoundly different geological histories for the Russian Arctic shelves. Using 3 D GIS to interrogate bathymetric, gravity and magnetic datasets, and to implement plate reconstructions, we seek to test these different models using geological constraints, and to consider their implications for hydrocarbon exploration on the Russian shelves.