Abstract
processes, as the region lacks complicating effects of continental remnants or
major volcanic plateaus. In particular, the most recently produced maps of the
free-air gravity field from satellite altimetry show in greater detail the previously
reported lineaments west of the East Pacific Rise (EPR) that are aligned with
plate motion over the mantle and originally suggested to have formed from
mantle convection rolls. In contrast, the gravity field 600 km or farther west of
the EPR reveals lineaments with varied orientations. Some are also parallel with
plate motion over the mantle but others are sub-parallel with fracture zones or
have other orientations. This region is covered by pelagic sediments reaching
~500-600 m thickness so bathymetry is not so useful for seeking evidence for
plate deformation across the lineaments. We instead use depth to basement
from three seismic reflection cruises. In some segments of these seismic data
crossing the lineaments, we find that the co-variation between gravity and
basement depth is roughly compatible with typical densities of basement rocks
(basalt, gabbro or mantle), as expected for some explanations for the lineaments
(e.g., mantle convection rolls, viscous asthenospheric inter-fingering or
extensional deformation). However, some other lineaments are associated with
major changes in basement depth with only subtle changes in the gravity field,
suggesting topography that is locally supported by varied crustal thickness.
Overall, the multiple gravity lineament orientations suggest that they have
multiple origins. In particular, we propose that a further asthenospheric interfingering instability mechanism could occur from pressure variations in the
asthenosphere arising from regional topography and such a mechanism may
explain some obliquely oriented gravity lineaments that have no other obvious
origin.
| Original language | English |
|---|---|
| Journal | Marine Geophysical Researches |
| Early online date | 19 Mar 2018 |
| DOIs | |
| Publication status | Published - 2018 |
Keywords
- oceanic thermal subsidence
- oceanic plate isostasy
- free air gravity anomalies
- Pacific plate deformation
- mantle dynamics
Fingerprint
Dive into the research topics of 'Equatorial Pacific gravity lineaments: interpretations with basement topography along seismic reflection lines'. Together they form a unique fingerprint.Projects
-
Geophysics
Mitchell, N. (PI), Mecklenburgh, J. (PI), Rutter, E. (PI), Huuse, M. (PI), Finch, E. (PI), Chandler, M. (PI), Chang, Y.-C. (PGR student), Zhao, Z. (PGR student), Shi, W. (PGR student), Bashir, Y. (PGR student), Ardo, B. (PGR student), Newton, A. (PGR student), Cox, D. (PGR student), Lloyd, C. (PGR student), Putuhena, H. (PGR student), Sarkar, A. (PGR student), Nnorom, S. (PGR student), Owolabi, O. (PGR student), Malah, M. (PGR student), Soutter, E. (PGR student), Dunlevy, E. (PGR student), Balila, A. (PGR student), Alhammami, S. (PGR student), Olobayo, O. (PGR student), Serié, C. (PGR student), Chenrai, P. (PGR student), Sharples, A. (PGR student), Le, A. (PGR student), Lamb, R. (PGR student), Harding, R. (PGR student), Gulmammadov, R. (PGR student), Calves, G. (CoI), Bureau, D. (CoI) & Muniz Pichel, L. (PGR student)
Project: Research