Open AccessAnalysis of satellite gravity and bathymetry data over Ninety‐East Ridge: Variation in the compensation mechanism and implication for emplacement process
Author(s) -
Tiwari V. M.,
Diament M.,
Singh S. C.
Publication year - 2003
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jb000047
Subject(s) - geology , ridge , seismology , bathymetry , crust , mid ocean ridge , ridge push , tectonics , seafloor spreading , lithosphere , underplating , geodesy , gravity anomaly , geophysics , paleontology , oceanography , oil field
We investigate the mode of compensation, emplacement history and deep density structure of the Ninety‐East Ridge (Indian Ocean) using spectral analyses and forward modeling of satellite gravity and bathymetry data. We find that the northern (0–10°N) and the southern (20–30°S) parts of the ridge are flexurally compensated with an effective elastic thickness >15 km, whereas the central part (0–20°S) is locally compensated. Furthermore, we find that for a part of central block (10–20°S, over Osborn Knoll) the compensation depth is unreasonably very high (30–40 km). Therefore we favor a model with subsurface loading and interpret this to be due to underplating of mafic material at the base of the crust, a hypothesis that is supported by seismic results and direct modeling of gravity data along some profiles. These results suggest that the northern and southern parts of Ninety‐East Ridge were emplaced off to a ridge axis compared to the central one, which might have been emplaced on or near a spreading center. Locally compensated large topography, thick underplated crust in the central part (near Osborn Knoll), might result from an interaction of a hot spot with the extinct Wharton spreading ridge.