thumbnail

Vertical motions of the Puerto Rico Trench and Puerto Rico and their cause

Journal of Geophysical Research B: Solid Earth

By:
DOI: 10.1029/2004JB003459

Links

Abstract

The Puerto Rico trench exhibits great water depth, an extremely low gravity anomaly, and a tilted carbonate platform between (reconstructed) elevations of +1300 m and -4000 m. I argue that these features are manifestations of large vertical movements of a segment of the Puerto Rico trench, its forearc, and the island of Puerto Rico that took place 3.3 m.y. ago over a time period as short as 14-40 kyr. I explain these vertical movements by a sudden increase in the slab's descent angle that caused the trench to subside and the island to rise. The increased dip could have been caused by shearing or even by a complete tear of the descending North American slab, although the exact nature of this deformation is unknown. The rapid (14-40 kyr) and uniform tilt along a 250 km long section of the trench is compatible with scales of mantle flow and plate bending. The proposed shear zone or tear is inferred from seismic, morphological, and gravity observations to start at the trench at 64.5??W and trend southwestwardly toward eastern Puerto Rico. The tensile stresses necessary to deform or tear the slab could have been generated by increased curvature of the trench following a counterclockwise rotation of the upper plate and by the subduction of a large seamount.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Vertical motions of the Puerto Rico Trench and Puerto Rico and their cause
Series title:
Journal of Geophysical Research B: Solid Earth
DOI:
10.1029/2004JB003459
Volume
110
Issue:
6
Year Published:
2005
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1
Last page:
16
Number of Pages:
16