International Tectonic Map of the Arctic (TeMAr): A Step toward Unraveling Geodynamic History of the Circum-Polar North

Oleg Petrov

TeMAr is a component of a major international project “Atlas of Geological Maps of Circumpolar Arctic at 1:5 000 000 scale” which was initiated in 2003 by geological surveys of Circum-Arctic states with active support from the CGMW. TeMAr’s objective is to integrate the earlier tectonic interpretations of the Arctic in the light of massive new data and to present the outcome in a legible cartographic format suitable for use as the basis for modern geodynamic reconstructions. TeMAr layout will include the 1:5 000 000 main map with cross-sections and the legend and smaller-scale maps and sketches of potential fields, sediment thickness, total crust thickness, solid crust thickness, types of crust and velocity models, tectonic provinces, etc. The paper products will be accompanied by digital model and attributive database. The following principles are applied in the compilation: - The term “orogeny” is reserved for convergence-related processes of deformation, magmatism and metamorphism leading to appearance of new continental crust. Orogenic assemblages are shown on the map by color polygons coded in accordance with the age of crust stabilization. - Intraplate reworking of older complexes resulted in structural, magmatic, metamorphic and/or isotopic overprint but not accompanied by appreciable growth of the crust is not acknowledged as orogeny. Such processes are shown on the map by overlay patterns against the background color indicating the age of primeval crust. - When possible, convergence-related versus intraplate environments and/or other geodynamic features of map units should be articulated by special overlay patterns and vector and/or point symbols. - Accretion of continental crust is paralleled by its destruction leading to breakup and opening of the ocean. This reverse geodynamic trend is primary reflected in rift-related magmatism (formation of LIPs and their individual major bodies), as well as in stretching and rifting of consolidated crust followed by its subsidence in the basement of sedimentary basins. Manifestations of both processes must be adequately shown on the map. - Clear distinction between oceanic and continental types of crust is a traditional obligation of tectonic cartography. The use of term “transitional crust” will be restricted to the areas of incomplete transformation of oceanic crust into continental (subduction-related arc-trench ensembles of recent active margins, possibly also some exotic intracontinental enclaves lacking full consolidation). Otherwise the continent-ocean partition should be specified by COB whose designation on the map will vary in accordance with the degree of confidence in its identification. Upgrading of the legend is continuously performed in the process of map compilation.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013