Holocene and Modern Dune Morphology for the Magdalena Coastal Plain and Islands, Baja California Sur, Mexico

Abstract

Moderate to well-defined Holocene and Recent dunes are present on the surface of the Magdalena coastal plain and on the top of sandy barrier islands of the Magdalena Lagoonal Complex in Baja California Sur, Mexico. Early Holocene to Late Holocene aeolian deposits are mostly mega barchans (20 to 60 m high), linear dunes (10 m high), dune ridges (60 to 80 m high), nabkha dunes (5 to 10 m high), and a sand sheet (20 m high). Modern dunes are mostly crescentic dunes (transverse and meso barchans, 5 to 10 m in height), a dune ridge (40 m high), foredunes (5 m high), and nabkhas (1 to 5 m high). Holocene dunes are covered by semi-desertic vegetation. The abandoned vegetated old dune scarps and evidences of sea water land intrusion suggest a local older higher sea level, which probably occurred at global Holocene maximum sea level. Present erosional and depositional processes can be observed on the modern local coasts.