P-wave tomographic images reveal that the northern Central America highlands east of the modern volcanic arc overlie a detached slab. Hypsometric analysis of the highlands in Honduras demonstrates that the region is a dissected plateau that is disrupted by normal faults near the North American–Caribbean plate margin. The dissected Central American plateau contains a network of superimposed rivers with meanders cut into bedrock; such a geomorphic character indicates that the regional uplift occurred in the absence of tilting. We propose that the epeirogenic uplift of northern Central America is the buoyant upper-plate response to the influx of mantle asthenosphere following the break-off and sinking of the slab.

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