34-7 Trace metals geochemistry as a proxy for redox and depositional conditions in sediments from active and inactive hydrothermal vents 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.: 7

Presenting Author:

Jair Ceja-González

Authors:

Ceja-González, Jair Carlos¹, Valdivieso-Ojeda, Jacob Alberto², Spelz, Ronald M.³, Delgadillo-Hinojosa, Francisco⁴, Huerta-Diaz, Miguel Angel ⁵, Caress, David W.⁶, Zierenberg, Robert⁷, Peña-Salinas, Manet Estefanía⁸

(1) Posgrado en Oceanografía Costera, Facultad de Ciencias Marinas/Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico, (2) Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Mexico, Mexico, (3) Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Baja California, , (4) Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico, (5) Universidad Autonoma de Baja California, Instituto de Investigaciones Oceanológicas, Ensenada, Baja California, Mexico, (6) Science Division, Monterey Bay Aquarium Research Institute, Monterey, California, USA, (7) Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA, (8) Laboratorio de Astrobiología, Instituto de Astronomía UNAM, Ensenada, Baja California, Mexico; Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico,

Abstract:

Redox-sensitive trace metals are widely used to reconstruct past environmental and depositional conditions in sedimentary systems, ranging from shallow marine settings to deep-sea hydrothermal environments. Recently discovered hydrothermal fields in the south Pescadero Basin, Gulf of California, Mexico, at depths of up to 3700 m provide a unique natural laboratory to investigate trace metal behavior across contrasting hydrothermal, seep-related, and background sedimentary conditions. In this study we present preliminary geochemical results from sediments collected in three distinct settings: (1) the Auka hydrothermal field, including active (Dianne) and diffusive (Matterhorn) vent sites; (2) the JaichMaa ‘ja ‘ag, comprising active vents, an  inactive vent , and methane seeps-influenced sediments; (3) non-hydrothermal sediments from the Cerralvo extensional system, located at a water depth of 963 m. Concentrations of redox-sensitive trace metals (Cu, Fe, Mn, Mo, V, Zn) and major elements (Ca, S) were measured using portable X-ray. Enrichment factors (EF_Me) and authigenic metal fractions were calculated relative to global shale background values. Sediment cores were collected using the ROV Subastian during Schmidt Ocean Institute expedition FK210922, aboard the R/V Falkor. Distinct authigenic metal concentrations and enrichment patterns clearly discriminate depositional environments. Hydrothermal sediments are characterized by elevated authigenic Cu, Mn, Mo, Pb, V, and Zn relative to the Cerralvo extensional system. Sediments from active vents at Auka and JaichMaa ‘ja 'ag) showed pronounced Mn enrichments, consistent with high-temperature fluid inputs and deposition of Mn-rich particles. In contrast, sediments influenced by methane seeps at JaichMaa ‘ja ’ag exhibited substantial Mo and V enrichments together with elevated authigenic S, reflecting anoxic-sulfidic conditions associated with anaerobic methane oxidation coupled to sulfate reduction. Hydrothermal sediments also exhibit contained the low authigenic Ca, Fe, and Sr, relative to non-hydrothermal sediments, suggesting limited carbonate precipitation and restricted reactive Fe availability, which may constrain pyrite formation, as documented in the Guaymas Basin. These results demonstrate that multi-proxy trace-metal signatures effectively discriminate between sediments affected by high-temperature hydrothermal fluids, diffusive venting, and methane seepage from those deposited in tectonically active but non-hydrothermal settings. Ongoing integration of these preliminary geochemical data with analyses of microbial diversity, heat-flow measurements, hydrothermal fluid chemistry, and sedimentation rates will allow identification of zones of enhanced microbially trace-metal mineralization and quantification of trace-metal burial fluxes in the southern Gulf of California.

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

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