34 Recent Advances in the Gulf of California Oblique Rift: Offshore and Onshore Studies // Avances Recientes en el Rift Oblicuo del Golfo de California: Estudios Marinos y Terrestres (Posters)

This session highlights recent research on the Gulf of California–Salton Trough plate boundary from ~12 Ma to today. We welcome terrestrial and marine studies involving tectonics, basin analysis, volcanology, sedimentology, and more. English or Spanish.

Friday, 24 April 2026
8:00 AM - 5:30 PM
LMH, 5th Floor Chapel

The Oldest Exposed Marine Sediments in the San José del Cabo Basin, Southern Baja California Peninsula

Paper number: 34-2
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

The San José del Cabo Basin owes its origin to the formation of the Gulf of California. Its basin fill consists of marine and terrestrial sedimentary rocks, comprising various geological formations ranging in age from upper Miocene to Pleistocene, in addition to Holocene deposits. The objective of this study was to identify the depositional environment and age of the marine sediments of the Trinidad Formation at Cerro (hill) Corona, located in the northern part of the basin. For this purpose, a 120-m stratigraphic section was measured. In general, sandstone, mudstone, and conglomerate crop out at this locality, reflecting depositional environments ranging from below fair-weather wave base to coastal-deltaic. A mudstone-dominated package containing calcareous nannofossils is intercalated in the middle part of the section. Although poorly preserved due to diagenetic processes, the following species were recognized: Discoaster berggrenii, D. quinqueramus, D. bellus, D. newellii, D. gemmulatus, D. blackstockae, D. asymmetricus, D. brouweri, D. hexaramus, D. variabilis, D. prolixus, and D. vinsonii. The age is constrained by the appearance of D. newellii in the lower NN11a zone (8.229 Ma), and the concurrence of the disappearance of D. bellus and the appearance of D. hexaramus in the lower NN11a zone (8.109 Ma). This suggests an age of ca. 8.2–8.1 Ma (late Tortonian) for the strata at Cerro Corona. To date, this is the oldest age reported for the Trinidad Formation in the San José del Cabo Basin.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-410817

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