Arctic Heat-flow Prediction from Gravity Inversion Mapping of Crustal Thickness and Continental Lithosphere Thinning
Nick J. Kusznir1 and Andy Alvey2
1Earth Interior Dynamics, Liverpool University, Liverpool, United Kingdom.
2Badley Geoscience, Hundleby, United Kingdom.
The basins of the Arctic formed during the Late Jurassic, Cretaceous and Tertiary as a series of small distinct ocean basins and rifts leading to a complex distribution of oceanic crust, rifted continental margins, micro-continents and ridges. The prediction of heat flow in such a complex tectonic region presents a substantial scientific and technical exploration challenge. We determine top basement heat-flow for the Amerasia and Eurasia Basins of the Arctic and their adjacent continental shelves using gravity inversion mapping of crustal thickness and continental lithosphere thinning. Crustal thickness, continental lithosphere thinning factors and ocean-continent transition location have been determined using a new gravity inversion method which incorporates a lithosphere thermal gravity anomaly correction. Data used in the gravity inversion is public domain gravity, bathymetry and sediment thickness data. Moho depths predicted from gravity inversion calibrate well with against seismic refraction estimates from the TransArctica-Arctica profiles across the Eurasia, Podvodnikov and Makarov Basins, and the Lomonosov Ridge. Continental lithosphere thinning and post-breakup residual thicknesses of continental crust determined from gravity inversion have been used to predict the preservation of continental crustal radiogenic heat productivity and the transient lithosphere heat-flow contribution within thermally equilibrating rifted continental margin and oceanic lithosphere. The resulting residual crustal radiogenic productivity and lithosphere transient heat flow components, together with base lithosphere background heat-flow, are used to produce regional maps of present-day Arctic top-basement heat-flow. The sensitivity of present-day Arctic top basement heat-flow to initial continental crustal radiogenic heat productivity, continental breakup age and oceanic lithosphere age has been examined.
AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.���������������������������