Satellite Measurements and Global Datasets in the Arctic: The Benefits of the ASEP Method

Susann Wienecke¹, Christine Fichler¹, Erik Lundin¹, Christopher Stadtler², and Christian Gram^2
1TPD, Research and Development, Statoil ASA, Trondheim, Norway.
²Exploration Excellence, Statoil ASA, Stavanger, Norway.

For a global tectonic study in poorly explored areas there is a clear advantage in using the worldwide coverage of satellite data. The most important item that is addressed here is the investigation of the crustal architecture in terms of plate boundaries, oceanic-continental transition, large scale faults, failed ridges, lower crustal bodies and other tectonic elements.

The derived spatial distribution of equivalent elastic thickness (Te) indicates significant structural units within the crust as a function of their isostatic response. Te of the Earth’s crust can be estimated using the analytical solution of the elastic plate called “ASEP method”. This method overcomes drawbacks of spectral methods and allows the calculation of flexural rigidity and Te with a higher spatial resolution.

Input data include satellite measured seafloor topography and potential field data merged with airborne, surface and submarine data.

The Circum Arctic region is presented as a case example. Since satellite data are so readily available the ASEP is a powerful tool in areas with limited access to seismic data. Low costs and low environmental impact are also obvious advantages.

We used the Arctic Gravity Project data compilation that consists of free-air anomalies offshore and Bouguer anomalies onshore. Integrated 3D density modelling and Te calculation with the ASEP method allow us to identify regions with different petrophysical properties, which may reflect anomalous parts of the crust (e.g. sutures, rift zones, lower crustal bodies).

The regional structures and/or lineaments proposed by the Te distribution should always be calibrated against other data or methods in order to verify an interpretation. Our results have revealed an anomalous intra-plate crustal structure. The features correlate well with other geo-scientific results. Combining all observations the feature can be linked to the location of a proposed suture zone.

Global datasets of potential field data form important constraints on the crustal architecture, which in turn is a fundamental aspect in plate reconstructions. The Circum Arctic crustal thickness map derived by gravity inversion correlates very well with other results also brings out previously unknown or subtle features. An example is the improved definition of the Laptev rift.

 

AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.

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