Deep Magnetic High Domains of the Circum-Arctic — What are the Structural Implications of These Features?

Rick Saltus¹, Elizabeth Miller², and Carmen Gaina^3
1U.S. Geological Survey, Denver, CO.
²Stanford University, Stanford, CA.
³Norwegian Geological Survey, Trondheim, Norway.

We have classified 14 distinct domains of the circum-Arctic magnetic anomaly field as “Deep Magnetic Highs”. These magnetic anomaly features are characterized by continuous high amplitude, long wavelength zones of high magnetic anomaly. The magnetic character of these domains implies that they are fundamental features of the Earth’s crust and they represent significant thicknesses of highly-magnetic material within the crust. Detailed study of two of these domains that lie in northern Alaska and northwest Canada support the idea that these magnetic features may represent zones of relatively high lithospheric strength that may influence regional tectonics and structure. These two particular domains coincide with constrictions in the width of the Cordilleran mobile belt and perhaps map structures that influence the position and shape of the thrust front. Globally there are other examples of coincidence of similar broad magnetic features with bends in regional mobile belts. Among the most notable global examples are features of the Andean thrust front in South America, the Zagros Mountains in the Middle East, and the Himalayan front in Asia. Similarly, within the circum-Arctic several of the deep magnetic highs are coincident with the edges of mobile belts. These include previously mentioned North Alaska and Mackenzie river domains as well as the North Verkhoyansk and Novaya Zemlya domains. In addition, there are number of these domains that fall within shallow continental shelf areas where the structural framework is not so well known. These include the Wrangell Island, East Siberian Sea, New Siberian Islands, Gydansky, Franz Josef Land, Lincoln Sea, and Amundson Gulf domains. In this presentation we will tour the “Deep Magnetic Highs” domains of the circum-Arctic and discuss their possible structural significance relative to regional tectonic understanding and current models for geodynamic evolution of the Arctic.

 

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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