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Magnetic polarity structure of the lower oceanic crust
Author(s) -
Allerton Simon,
Tivey Maurice A.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl008493
Subject(s) - geology , outcrop , lineation , paleomagnetism , crust , seafloor spreading , oceanic crust , ridge , seismology , magnetic dip , seabed , geophysics , paleontology , tectonics , oceanography , subduction
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 deep‐towed 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°.