ABSTRACT
The Cabo Rojo beach-ridge plain was formed in a low-energy shadow behind the Blanquilla-Lobos coral-reef tract. The source of the sand comprising Cabo Rojo was offshore material of Wisconsin (?) age, most probably deposited by the Rio Panuco during a lower sea-level stand. Islands within the Laguna de Tamiahua define a sandstone body similar in shape and orientation to that of Cabo Rojo, strongly suggesting either a 2-stage Holocene constructional history, or the remains of a pre-Wisconsin barrier.
The beach-ridge plain consists of low, hummocky ridges (relief less than 1 m, spacing of 100 m) oriented parallel with the present coast. This coast is undergoing erosion, and beach ridges are not forming. Cliffed, back-beach dune ridges are found on the northern and southern parts of Cabo Rojo, the northern ridges being best developed. Longshore drift compartmentalization has been effected along this coast by the Blanquilla-Lobos offshore reef tract.
