EarthRef.org Reference Database (ERR) -- Allerton & Tivey 2001

A newly developed rock drill was used to take the first fully oriented samples from in-situ gabbros exposed on Atlantis Bank, which formed 11 m.y. ago on the Southwest Indian Ridge (SWIR). These paleomagnetic data locate the seabed outcrop of a normal polarity magnetic lineation within an outcrop of lower crust that correlates with overlying deeptowed and sea-surface magnetic field measurements. A systematic lateral offset between the seabed boundary and measured anomalies implies that the reversal boundary dips ~25¿ to the south, away from the ridge axis. Paleomagnetic results suggest that following magnetization acquisition, the platform tilted south by ~20¿ (range: 33 south¿ to 7¿ north), implying an original reversal boundary dip of only ~5¿. ¿ 2001 American Geophysical Union A newly developed rock drill was used to take the first fully oriented samples from in-situ gabbros exposed on Atlantis Bank, which formed 11 m.y. ago on the Southwest Indian Ridge (SWIR). These paleomagnetic data locate the seabed outcrop of a normal polarity magnetic lineation within an outcrop of lower crust that correlates with overlying deeptowed and sea-surface magnetic field measurements. A systematic lateral offset between the seabed boundary and measured anomalies implies that the reversal boundary dips ~25¿ to the south, away from the ridge axis. Paleomagnetic results suggest that following magnetization acquisition, the platform tilted south by ~20¿ (range: 33 south¿ to 7¿ north), implying an original reversal boundary dip of only ~5¿. ¿ 2001 American Geophysical Union