Tectonic Heat Flow during the Pangaean Permo-Carboniferous Orogenic Collapse: Implications for the Arctic

Damien Bonté², J. Maccauley¹, Jan-Diederik van Wees¹, Randell Stephenson³, and Susanne Nelskamp^1
1Geo-Energy and Geo-Information, TNO, Utrecht, Netherlands.
²Tectonics Department, Vrije Universiteit, Amsterdam, Netherlands.
³School of Geosciences, University of Aberdeen, Aberdeen, United Kingdom.

Basement heat flow is one of the most influential parameters on basin maturity. Although rapid progress has been made in the development of tectonic models capable of modelling the thermal consequences of basin formation, these models are hardly used in basin modelling. In this paper we investigate the added value of novel tectonic heat-flow models capable of inverting burial history to paleo heat flow trends, consistent with various geodynamic development scenarios (including rifting, underplating and mantle upwelling) The model has been applied for a range of basin settings and predicted temporal and spatial heat flow variations are in close accordance with observations on heat flow for specific tectonic settings.

In this paper we focus on the implications of tectonic heat flow prediction for the Permo-Carboniferous maturity-depth trends. The Permo-Carboniferous was characterized, globally, by a strong destabilization of lithosphere following the formation of Pangaea. The processes governing the transformation of orogenically destabilized lithosphere into early Jurassic stabilized lithosphere can be inferred from quantitative subsidence analysis. Results from well-studied basins, such as Southern Permian Basin, allow us to demonstrate that orogenic collapse mechanisms were dominant and that these produced significant regional elevations of heat flow at the Permo-Carboneferous boundary. The elevated heat flow trends were locally enhanced by magmatism. Maturity-depth trends can consequentlyshow a significant break at the Permo-Carboniferous boundary and, in the Netherlands for example, this has had a dramatic impact on maturity evolution.

Some Arctic sedimentary basins - such as the Sverdrup Basin in northern Canada and its Late Palaeozoic equivalents off Alaska and Svalbard - may have had a somewhat similar, post orogenic-collapse style of tectonic development in the Permo-Carboniferous. In such basins, we can infer that heat flow was most likely elevated in a similar fashion as in the European Permian basins and, here, we demonstrate the implications of such an elevated heat flow history for the Sverdrup Basin. In general, for new areas opening up for exploration in the Arctic, our findings argue for taking into account an elevated Permo-Carboniferous heat flow scenario as hydrocarbon maturity and expulsion at stratigraphic levels deeper than this level boundary may have occurred earlier than would have otherwise been anticipated.

AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia