34-6 Spatial Variability of Heat Flow in Hydrothermal Systems of the Southern Pescadero Basin, Gulf of California

Session: 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)

Poster Booth No.: 6

Presenting Author:

Isabela Macias Iñiguez

Authors:

Macias Iñiguez, Isabela¹, Negrete-Aranda, Raquel², Spelz, Ronald M.³, Vega-Ramírez, Luis Angel⁴, Contreras, Juan⁵, Harris, Rob⁶

(1) Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, México, Baja California, Mexico, (2) Ciencias de la Tierra, CICESE, Ensenada, Baja California, Baja California, Mexico, (3) Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico, (4) Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico, (5) Ciencias de la Tierra, CICESE Departamento de Geologia, Ensenada, BC, Mexico, (6) College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA,

Abstract:

The Gulf of California is an active transtensional plate boundary characterized by normal and strike-slip faulting that generates a series of pull-apart basins. Crustal thinning, magmatic intrusions, and high sedimentation rates associated with this tectonic regime strongly influence the thermal structure of the lithosphere and promote the development of sediment-hosted hydrothermal systems. In these settings, hydrothermal circulation is closely linked to fault networks, magmatic heat sources, and variations in sediment permeability, playing a key role in lithospheric heat dissipation and fluid–rock interactions.

The Southern Pescadero Basin (SPB) is a deep-water basin within the Pescadero Basin Complex in the southern Gulf of California, where transtensional deformation and crustal thinning have produced a highly fractured and thermally anomalous seafloor. This tectonic configuration has facilitated the development of the Auka and JaichMaa ’ja’ag hydrothermal vent fields. High-resolution bathymetry and shallow acoustic profiles reveal sediment cover over crystalline basement, major fault structures, and laterally extensive acoustically transparent zones interpreted as subsurface hydrothermal fluid accumulations. The spatial association between these features, elevated heat flow, and active venting suggests the presence of a magmatic heat source, likely linked to sill emplacement or shallow magmatic intrusions that drive hydrothermal circulation.

Building on this structural framework, this ongoing study integrates sub-bottom profiling and direct heat flow measurements to investigate the thermal and hydrological processes governing fluid circulation in the SPB. While the presence of venting is documented, the spatial variability of heat flow and its relationship with sediment properties and fault-controlled permeability are not yet fully understood. This research aims to quantify spatial variations in heat flow and assess the role of sedimentary and structural controls in regulating hydrothermal circulation. Ultimately, this work contributes to a deeper understanding of how sediment-hosted systems dissipate lithospheric heat and support unique chemosynthetic ecosystems.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3, 2026

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.