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Rift asymmetry and continental uplift
Author(s) -
Doglioni Carlo,
Carminati Eugenio,
Bonatti Enrico
Publication year - 2003
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2002tc001459
Subject(s) - geology , asthenosphere , lithosphere , rift , ridge , mantle (geology) , bathymetry , mid ocean ridge , ocean surface topography , continental margin , seafloor spreading , asymmetry , paleontology , tectonics , oceanography , physics , quantum mechanics
The topography of ocean ridges and rifts show a distinct asymmetry. The eastern sides of the East Pacific Rise, the Mid‐Atlantic Ridge, and the NW Indian Ridge are, on average, 100–300 m more elevated than the conjugate flank to the west. The asymmetry is maintained when bathymetry is plotted versus the square root of crustal age. A comparable topographic asymmetry occurs in the Red Sea and Baikal rifts where the “eastern” continental shoulders are more elevated. We suggest that depleted and lighter asthenosphere generated below the ocean ridge was shifted “eastward” relative to the lithosphere, determining a density deficit below the eastern flank. The eastward migration of the lighter Atlantic asthenosphere below the African continent could eventually have contributed to the anomalous postrift uplift of Africa. This model suggests that the “westward” drift of the lithosphere relative to the underlying mantle might be a global phenomenon.