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Divergence, expressed as the angle between the plate motion vector and the azimuth of a plate margin fault, has been proposed to explain development of contrasting styles of transtensional deformation along transform margins. We present the western North America–Caribbean plate margin as a test of this hypothesis. Here, geologic, earthquake, marine geophysical, and remote sensing data show two distinct structural styles: (1) east-west extension along north-trending rifts normal to the plate margin in the western study area (western Honduras and southern Guatemala); and (2) NNW-SSE transtension along rifts subparallel to the plate margin in the eastern study area (northern Honduras and offshore Honduran borderlands region). Orientations of rifts in each area coincide with the angle of divergence between the GPS-derived plate motion vector and the azimuth of the plate boundary fault, such that the western zone of east-west extension has an angle >10°, while the eastern zone of NNW-SSE extension occurs when the angle of divergence is between 5° and 10°. A narrow transition area in north-central Honduras separates the plate boundary–normal rifts of western Honduras from the plate boundary–parallel rifts to the east.

Faults of the offshore Honduran borderlands extend onshore into the Nombre de Dios range and Aguan Valley of northern Honduras where tectonic geomorphology studies show pervasive oblique-slip faulting with active left-lateral river offsets and active uplift of stream reaches. Offshore, exploration seismic data tied to wells in the Honduran borderlands reveal active submarine faults bounding asymmetric half-grabens filled by middle Miocene clastic wedges with continued clastic deposition into Pliocene-Pleistocene. The north-trending rifts of western Honduras form discontinuous half-grabens that cut late Miocene ignimbrite strata. Plate reconstructions indicate the north-trending rifts of western Honduras developed in response to increased interplate divergence as the western margin of the Caribbean plate shifted from the Jocotan fault to the Polochic fault during the middle Miocene.

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