41 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 (Part III)
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
1:30 PM - 5:30 PM
LMH, Fiesta Terrace Salon
How does the cumulative interaction of diverse faulting mechanisms shape the long-term tectonic evolution of the Gulf of California? The Yuha Desert case of study
Paper number: 41-2
Program: Technical Sessions
Time: 1:55 PM – 2:15 PM
Authors
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Anjuly Astarte Jasso Lara Presenting AuthorCentro de Investigación Científica y de Educación Superior de Ensenada, Baja California (CICESE), Ensenada, Baja California
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John FletcherCentro de Investigación Científica y de Educación Superior de Ensenada, Baja California (CICESE), Ensenada, Baja California
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Thomas RockwellSan Diego State University, San Diego, California
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Christophe PascalRuhr University Bochum, Bochum, Renania del Norte- Westfalia
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Antonio González FernándezCentro de Investigación Científica y de Educación Superior de Ensenada, Baja California (CICESE), Ensenada, Baja California
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Claudio InguaggiatoCentro de Investigación Científica y de Educación Superior de Ensenada, Baja California (CICESE), Ensenada, Baja California
Abstract
Existing kinematic models struggle to reconcile the roles of lateral and extensional faults in accommodating transtensional deformation during the opening of the Gulf of California (GoC). We propose that these fault systems have operated concurrently since the onset of shear (~16–12 Ma), challenging conventional two-stage rifting models. We argue that kinematic variability is essential for accommodating three-dimensional transtensional deformation, and that the extensional and lateral components of strain do not correspond to discrete changes in regional opening direction across the GoC. Our study area in the Yuha Desert is located near the axis of the transtensive shear zone between the Pacific and North American plates, within the northern GoC.
We characterize fault geometry, cross-cutting relationships, and kinematics to demonstrate that the region is deformed by a complex array of high-angle faults (HAFs) and low-angle faults (LAFs) that generated extensional basins filled with Middle Miocene to late Quaternary sedimentary sequences. Faults are grouped into four categories based on geometry and kinematics: (1) NW-striking dextral HAFs, including the Laguna Salada fault (LSF); (2) NNW-striking normal HAFs; (3) ENE–NE–NNE-striking sinistral-normal HAFs; and (4) east-directed LAFs.
Transtensional shear is strongly partitioned at branching intersections between Group 1 and Group 2 faults, where the extensional component of deformation is preferentially accommodated on the more NNW-striking branches, while dextral strike-slip is localized on the WNW-striking branch, identified here as the principal strand of the LSF. All fault groups exhibit mutual cross-cutting relationships, indicating coeval activity since the onset of rifting. Additionally, all groups contain segments with Late Quaternary coseismic scarps, demonstrating that they remain active today.
Across most of the Yuha Desert, kinematic T axes derived from all four fault groups are subparallel and trend WSW–ENE. In contrast, T axes associated with ENE-striking sinistral faults in the northern part of the study area trend WNW. This pattern may reflect local fault rotation or spatial variations in stress orientation; however, cross-cutting relationships preclude temporal changes in the regional stress field.
These observations indicate that the Yuha Desert domain has been dominated by the extensional component of transtensional strain since rifting initiated at ca. 12.3 Ma. Ongoing work includes mechanical interaction analyses, paleostress modeling, and slip tendency analysis to develop a comprehensive structural model of fault system evolution.
Geological Society of America Abstracts with Programs. Vol. 58, No. 3
doi: 10.1130/abs/2026CD-410814
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