Its western end is in contact with the continental Chortis block lying along a late cretaceous convergence zone where the Mesquito composite oceanic terrane is exposed.

The land bridge had finished forming around 3.5 million years ago during the late Pliocene–early Pleistocene with the closing of the Caribbean-Pacific seaway.

[4] Initial geologic studies of Central America revealed structural and stratigraphic differences between its northern and southern regions.

Later studies grouped the regions of Honduras, Nicaragua, El Salvador and portions of Guatemala onto the structure termed the Chortis block.

[7] Gómez Tapias, Jorge; Montes Ramírez, Nohora E.; Almanza Meléndez, María F.; Alcárcel Gutiérrez, Fernando A.; Madrid Montoya, César A.; Diederix, Hans (2015).