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Project Progress

Long experience in isotopic geochemistry and paleomagnetism has demonstrated that results from studies based on properly collected drill core are vastly superior to surface samples. During the past year we experimented with an inexpensive, 2-person Winkie drilling system, jointly owned and operated by the Kirschvink group at Caltech and Prof. Nic Beukes at the University of Johannesberg in South Africa. The goal was to obtain a continuous core across the terrestrial P/T extinction 'event beds’ in the Karoo basin of South Africa. The operation was an incredible success, with the core being obtained in only 5 working days. Two video clips we have posted on our www site, showing the coring operation (http://www.gps.caltech.edu/users/jkirschvink/MVI_1798.AVI ) as well as the removal of a single 1.5 m core chunk from our 1.5 m long core barrel (http://www.gps.caltech.edu/users/jkirschvink/MVI_1799.AVI ).

This Karoo Core has nearly 100% recovery through 37.5 meters of section, tilting at an angle of 13º to the bedding. Numerous small bedding planes preserve clear elliptical outlines, allowing perfect core orientation and dip control for the entire length. The chippy, friable claystones that we had to glue together piece by piece to do the paleomagnetic studies reported earlier can now be sampled at a sub-cm resolution, if needed. All of the Smith/Ward event beds are there in their glory, as well as a massive paleosol below them that is obviously the ‘end Permian Paleosol’. The core is freckled throughout with small carbonate soil nodules, difficult to find in weathered surface materials, that will make the geochemists salivate, and on occasion there are little sulfide blebs in some of the greenish claystones. The core is balanced halfway between the Red/Green and pure Green claystone/sandstone, and must therefore span the basal Permian geomagnetic reversal.