Miocene to Holocene Extensional Tectonics and Volcanic Stratigraphy of NE Baja California, Mexico

Abstract

Northeastern Baja California presently experiences active extensional and strike-slip faulting related to the transtensive Pacific-North America plate boundary in the Gulf of California. Some of the active structures are fairly new, whereas others appear to have a movement history as far back as Miocene time. This trip focuses on the history of Miocene to Recent extension, and its relation to the development of the Pacific-North America plate boundary, in the Gulf Extensional Province of NE Baja California. We will see the extensional structures at the latitudes of San Felipe to Puertecitos, and view the stratigraphic relationships of the volcanic and marine rocks that constrain the timing of this extension. Several major structural features are well-exposed here: the Main Gulf Escarpment and its structural variations along strike; the E-W variations in extensional styles within the extensional province; the extreme narrowing of the Gulf Extensional Province near El Huerfanito; and evidence for variations in timing and amount of extension throughout the extensional province.