Early Rift Sedimentation and Structure along the NE Margin of Baja California

Abstract

This field trip will examine deposits and structures in four basins of NE Baja California which formed during Neogene rifting in the Gulf of California Extensional Province (Fig. 1). Our objective is to provide an overview of depositional environments and facies, and tectonic controls on the basin evolution, as a guide to interpreting early rift basins elsewhere around the Gulf of California as well as at other incipient oceanic rifts. The basins we will visit range in age from middle Miocene (the continental deposits of the Santa Rosa basin) to late Miocene (upper part of the Santa Rosa basin, and the San Felipe marine sequence) to Pliocene (San Felipe marine sequence, Puertecitos Formation, and Laguna Salada sequence). They include both marine and nonmarine deposits, and record variations in sedimentation rate and tectonic patterns that are regionally important in the thermal and structural evolution of the northern Gulf of California. They also lie in different structural settings within the rift system.