Paleomagnetic results from Honduras and their bearing on Caribbean tectonics

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Abstract
Paleomagnetic results have been obtained from 37 sites in central and western Honduras and one site in north‐western Nicaragua. The rocks are limestones, sandstones, and granites and range in age from 140 to 60 m.y. Regional fold‐tests demonstrate that the rocks carry a prefolding (pre‐Laramide) magnetization. The data indicate a very large clockwise rotation of the sampling area during the Early Cretaceous followed by a counter‐clockwise rotation in the Late Cretaceous. The changes in latitude are minor during this time period. It is highly unlikely that these large rotations apply to the entire Caribbean plate. Rather, they reflect the motion of a smaller area known as the Chortis Block. This interpretation is supported by paleomagnetic data from neighboring areas. The results also suggest that the Chortis Block sutured onto southern Mexico/Guatemala in Latest Cretaceous time in agreement with geochemical data and several plate tectonic models. These new data together with published paleomagnetic data from around the Caribbean imply that a rigid Caribbean plate did not exist until well into the Tertiary.