--> Abstract: Evolution of the Caledonian Orogenic Crust and the Tectonic Linkages to Basin Formation in NE Greenland during the Late Palaeozoic, Mesozoic, and Tertiary, by James Helwig; #90177 (2013)

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Evolution of the Caledonian Orogenic Crust and the Tectonic Linkages to Basin Formation in NE Greenland during the Late Palaeozoic, Mesozoic, and Tertiary

James Helwig

Three phases of deep 2D seismic acquisition and PSDM processing was carried out by Ion Geoventures from 2008 to 2012, to provide regional coverage of the NE Greenland Atlantic passive margin, which to date remains undrilled. The interpretation of these three surveys, together with constraints of regional geological and potential fields data, has been previously discussed by Helwig et al (2012). In 2012 ARKeX completed an airborne Full Tensor Gravity (FTG) survey for Ion over the area for both the pre-round blocks open to the KANUMAS Group, and also the blocks to be included in the 2013 Greenland Licensing Round. The multi-client FTG survey is the largest ever acquired offshore, and covers 50,000 sq.km. The high resolution gravity gradiometry and magnetics have been integrated with the existing dataset interpretation, and this has led to an improved understanding of fault linkages both within and above Caledonian basement, basement composition, the distribution of igneous/volcanic components, and especially the geometry of salt structures within the area. The main area for discussion will correspond to the area located within the boundary of the high resolution FTG Survey : the Permian Salt Province (DKshavn Basin); the DKshavn Ridge Area; and the Thetis Basin Area. The PSDM seismic data extends to the order of 40Km depth, and in certain orientations excellent and coherent deep (10-30km) seismic signal is present, and together with high quality shallower seismic signal (<10km) provides an excellent starting point for building 2D interpreted sections which in turn can be tested for differing interpretation by using iterative potential fields modelling. i.e. ensuring consistency of interpretation across all datasets. For example some regional seismic dip lines show that high resolution gravity gradiometry and magnetic trends are aligned, with high / low gravity signal matching corresponding high/low magnetic signal. However, there are regions where the two datasets show offset between crestal gravity and magnetic highs. Detailed 2D/3D iterative modelling has allowed the architecture and the nature of the highly heterogeneous basement to be interpreted, and a linkage to be deduced between the extensional/transtensional (and localised transpressional) faulting of the Late Palaeozoic, Mesozoic, Cretaceous and Tertiary, and inter-crustal detachments which were initiated during the Caledonian Orogeny. In addition to the increased understanding of the Thetis Basin and DKshavn Ridge, the high resolution gravity gradiometry has enabled salt volumes and enhanced structural definition of salt-related structuring to be increased between seismic lines over 30 kms apart. The array of basins and their deep architecture suggests a west to east, chronological progression of pre-rift, sag and oceanic rift basins in the NE Greenland shelf and slope.

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