Tectonics

Neogene Caribbean Plate rotation and associated Central American tectonic evolution

Authors

  • G. Wadge,

  • K. Burke


Abstract

During the Neogene the Caribbean plate moved eastward with respect to the North and South American plates. Reconstructing this motion by closing the Cayman Trough along its bounding transform faults creates a gore of ocean between northern Central America and southern Mexico. We present, instead, a reconstruction which juxtaposes these two continental areas by strike slip motion. Using geological evidence from around the Cayman Trough, the strike-slip fault zones of northern Central America, and the continental margin of southern Mexico as our constraints, we propose that seafloor spreading began in the Cayman Trough at 30 ± 5 Ma and that subsequently there was 1100 km of relative plate displacement at an average rate of 3.7 ± 0.6 cm/yr. This Neogene plate motion cannot be achieved by rigid plate rotation about a single pole, which implies that Central America must have rotated anticlockwise relative to the rest of the plate. There is evidence for internal plate deformation in Central America consistent with such a sense of rotation. Our suggestion of an originally easterly trending arc in southern Central America is more consistent with the timing and geometry of the collision of Panama with northern Colombia and the resultant deformation than were earlier models that depicted collision of a northerly trending arc.

Ancillary