Three-dimensional gravity inversion model of the deep crustal structure of the central Drake Passage (Shackleton Fracture Zone and West Scotia Ridge, Antarctica).

Gravity and bathymetric data collected by the Spanish R/V Hespérides over the Shackleton Fracture Zone (SFZ) and the West Scotia Ridge (WSR) were used to invert for the three-dimensional (3-D) structure of the deep crust. Data from the Global Gravity Grid and Global Seafloor Topography (GGSFT) were...

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Bibliographic Details
Published in:Journal of Geophysical Research: Solid Earth
Main Authors: Flores-Márquez, E. Leticia, Suriñach, Emma, Galindo Zaldívar, Jesús, Maldonado, Andrés
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union 2003
Subjects:
Exploration Geophysics
Remote sensing
Plate tectonics
Inverse theory
Mathematical Geophysics
Drake Passage
Shackleton
Shackleton Fracture Zone
West Scotia Ridge
Antarc*
Antarctica
Online Access:http://hdl.handle.net/10261/18990
https://doi.org/10.1029/2002JB001934
Description
Summary:Gravity and bathymetric data collected by the Spanish R/V Hespérides over the Shackleton Fracture Zone (SFZ) and the West Scotia Ridge (WSR) were used to invert for the three-dimensional (3-D) structure of the deep crust. Data from the Global Gravity Grid and Global Seafloor Topography (GGSFT) were also employed to enlarge the cruise area. The merged data were analyzed to determine 3-D deep structure by numerical inversion. Water layer contribution to the gravity anomaly was eliminated, taking into account the bathymetry. Spectral analysis of the reduced data yielded mean crust-mantle interface (CMI) depths of 10.5 +/- 1.2 km. Inversion of the regional anomaly gave a 3-D detailed geometry of the CMI, which generally agrees with the 2-D models established along profiles where gravity data and multichannel seismic lines are available. The WSR shows an asymmetrical structure with a reverse fault located southeastward to the central valley. This fault was developed, probably, as a consequence of the NW-SE compressive deformations, which occurred following the spreading. The 3-D view shows that the SW end of the spreading axis was affected more intensely by the compression. The SFZ represents an active sinistral transpressive fault zone of the Scotia-Antarctica plate boundary and shows crustal thickening related to bathymetric highs. The crustal thinning detected at the intersection with the inactive WSR suggests a complex interaction between these two structures. Peer reviewed

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