Evolution of Fold and Thrust Belt in Offshore Mackenzie River Delta: Interpretation from Long-Offset Arcticspan(TM) 2-D Seismic Data
Menno G. Dinkelman1, Naresh Kumar2, James Helwig2, Peter A. Emmet2, and James W. Granath2
1BasinSPAN Programs, ION Solutions-GX Technology, Houston, TX
2Consultant, ION Solutions-GX Technology, Houston, TX
The Beaufort-Mackenzie Basin (Arctic Canada) is a petroliferous province in the early stages of exploration: despite no sizable production exists in the area, 48 discoveries have led the USGS to estimate mean undiscovered resources in shallow water at 14.5 BB of liquids (2.3 BCM) and 86.6 TCF gas (2.32 TCM). The major discoveries so far have been in the fold-thrust belt and associated structures in the southern and western part of the basin where most of exploration has concentrated on the inner shelf. This structural province extends to almost 2 km water depth.
To clarify the regional framework, especially in deep water, ION Geophysical (GX Technology) acquired 9,095 km of 2-D long-offset seismic data in two phases in 2006 and 2007. The program was designed to image down to the base of the crust with a 9 km-long cable, 18-second recording, and final depth processing (PSDM) to 40 km.
The deep marine BeaufortMackenzie fold and thrust belt is quite unusual among the major fold and thrust belts in the world. It is part of both a K-T passive margin deltaic prism of the Arctic Ocean and a foreland basin of the NW Canadian/NE Brooks Range Cordillera. Thus its tectonic evolution must be interpreted in the context of contemporaneous and episodic interaction of crustal compression in the Cordillera and in the down-slope gravitationsl forces exerted by Mackenzie River sediments on the Canada Basin.
After the initial opening at approximately 150 ma, active sea-floor spreading took place from 130 to 80 ma at which point the Mackenzie River system started to deposit a thick sedimentary wedge. Although the area is still tectonically active, major compressional deformation took place in phases between 60 and 25 ma ago. It is possible that some of the deep-water structures were formed by younger episodes of compression that caused structural inversion at a very deep level.
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