The Chortis block (Honduras, El Salvador and environs) is a microcontinental block at the northwestern end of the Caribbean plate which may have been transported east from southern Mexico during the Cenozoic opening of the Cayman Trough. However little is known about the tectonic history of this block. This project will gather kinematic data on Cenozoic faulting to help determine slip directions and to infer stress regime and estimate displacements to see if significant Cayman Trough offset is absorbed within the block. In an effort to place age constraints on the tectonic history, U-Pb, 40Ar/39Ar and fission track ages on granitoids and volcanic rocks will be carried out. These data will allow testing of the hypothesis that the Chortis block originated from the truncated southern margin of Mexico, and generally improve the understanding of the transport of microcontinental blocks along a large offset transform fault.