Ultra-Slow Tectonics, Sediment Drifts, and Gas Hydrates in the Arctic Fram Strait
Monday, 15 December 2014: 9:15 AM
Sediment drifts form > 1000 m thick and > 100 km long elongated ridges along many carbon-rich continental margins creating potential reservoirs for gas and gas hydrate. Drifts develop under geostrophic currents that are often influenced on tectonic timescales by ocean basin development. Here, we discuss the tectono-sedimentary evolution of a growing Arctic gas and gas-hydrate charged sediment drift on oceanic crust in eastern Fram Strait, the tectonic controlled and only deep-water gateway between the subpolar North Atlantic and Arctic Ocean. Ultraslow-spreading between NW Svalbard and NE Greenland restricts ocean basin development here permitting the unique interaction of a mid-ocean ridge transform fault with a developing sediment drift since the Late Miocene. Geophysical data constrain the timing of a 30 km lateral offset of the gas hydrate-charged deep-water sediment drift across the Molloy Transform Fault. Our reconstruction shows the drift expanded greatly during the intensification of northern hemisphere glaciation at 2.7 Ma and was deposited across the transform and subsequently offset during the last 2 Ma. We describe an early gas charge model for the development of the deep-water gas hydrate system here and suggest it could be as old as 2 Ma.