--> Abstract: New Constraints on the Age of the West Greenland Volcanic Province from 40Ar/39Ar Dating, by Catherine Nelson; #90177 (2013)

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New Constraints on the Age of the West Greenland Volcanic Province from 40Ar/39Ar Dating

Catherine Nelson

The West Greenland volcanic province forms part of the North Atlantic Igneous Province (NAIP), which is preserved in fragments from Baffin Island to the UK following the opening of the North Atlantic. The onshore part of the West Greenland volcanic province, covering an area of approximately 22,000km2, has been extensively studied and is thought to contain the first products of the present-day Iceland Plume (Larsen and Pedersen, 2009). The onshore succession spans an age range from approximately 61 to 52.5 Ma (Storey et al., 1998). Comparatively little is known about the offshore part, which covers an area of around 90,000km2 (Skaarup, 2001), and prior to 2010 only one exploration well (Hellefisk-1) had penetrated the volcanic succession. This gave an age of 57.7 ± 1.2 Ma using 40Ar/39Ar geochronology. Here, we present additional constraints on the age and nature of the offshore volcanic succession. The Delta-1 well, drilled by Cairn Energy in summer 2011, reached its TD within lava flows of the West Greenland volcanic province. The well is located 112km WSW of Svartenhuk Halvø, offshore West Greenland, in 293m of water. Analysis of wireline log data showed that the volcanic succession was made up of subaerial lava flows, and a sidewall coring programme was carried out to obtain more data on the volcanic succession. 23 sidewall cores collected within the volcanic succession were analysed for major and trace element compositions using XRF spectroscopy. These results were compared with onshore data to investigate possible correlations, and the data were also used to select the freshest samples for dating. Six sidewall cores were selected for dating using 40Ar/39Ar geochronology, and sample preparation and analysis was carried out by the Open University. The overall age trend for all six samples was stratigraphically consistent, with an overlapping result from four of the samples, and two of these had extremely low errors. A strategy of targeted side wall sampling in the Delta-1 well through the volcanic sequence has provided significant additional data for the offshore West Greenland volcanic province. The results of the XRF analysis and 40Ar/39Ar geochronology will be presented, and the implications for West Greenland and the rest of the NAIP will be discussed. References Larsen, L.M., and Pedersen, A.K., 2009. Petrology of the Paleocene Picrites and Flood Basalts on Disko and Nuussuaq, West Greenland. Journal of Petrology, v. 50, p. 1667-1711. Skaarup, N., 2001. Offshore volcanic rocks in Baffin Bay. Danmarks og Grønlands Geologiske Undersøgelse Rapport 2001/117, 153pp. Storey, M., Duncan, R.A., Pedersen, A.K., Larsen, L.M. & Larsen, H.C. 1998:40Ar/39Ar geochronology of the West Greenland Tertiary volcanic province. Earth and Planetary Science Letters v. 160, p. 569–586.

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