Vertical motions of the Puerto Rico Trench and Puerto Rico and their cause
ten Brink, Uri S.
MetadataShow full item record
KeywordDynamic topography; Slab tear; Puerto Rico trench; Caribbean plate; Challenger Deep; Seamount subduction
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.
This paper is not subject to U.S. copyright. Published in 2005 by the American Geophysical Union. The definitive version was published in Journal of Geophysical Research 110 (2005): B06404, doi:10.1029/2004JB003459.
Suggested CitationJournal of Geophysical Research 110 (2005): B06404
Showing items related by title, author, creator and subject.
Tucholke, Brian E.; Eittreim, Stephen (American Geophysical Union, 1974-09-20)Nephelometer measurements in the Puerto Rico trench record a midwater light scattering maximum at the depth of the near-bottom nepheloid layer found in the deep Atlantic basin to the northwest. This midwater maximum is ...
Meighan, Hallie E.; Pulliam, Jay; ten Brink, Uri S.; Lopez-Venegas, Alberto M. (American Geophysical Union, 2013-06-14)The fore‐arc region of the northeast Caribbean plate north of Puerto Rico and the Virgin Islands has been the site of numerous seismic swarms since at least 1976. A 6 month deployment of five ocean bottom seismographs ...
ten Brink, Uri S.; Danforth, William W.; Polloni, Christopher; Andrews, Brian D.; Llanes, Pilar; Smith, Shepard; Parker, Eugene; Uozumi, Toshihiko (American Geophysical Union, 2004-09-14)The Puerto Rico Trench, the deepest part of the Atlantic Ocean, is located where the North American (NOAM) plate is subducting under the Caribbean plate (Figure l). The trench region may pose significant seismic and tsunami ...