Sill Stacking in Subseafloor Unconsolidated Sediments and Control on Sustained Hydrothermal Systems: Evidence From IODP Drilling in the Guaymas Basin, Gulf of California

Abstract Magma emplacement in the top unconsolidated sediments of rift basins is poorly understood. We compare two shallow sills from the Guaymas Basin (Gulf of California) using core data and analyses from IODP Expedition 385, and high‐resolution 2D seismic data. We show that magma stalling in the top uncemented sediment layer is controlled by the transition from siliceous claystone to uncemented silica‐rich sediment, favoring flat sill formation. Space is created through a combination of viscous indentation, magma‐sediment mingling and fluidization processes. We show that sills emplace above the opal‐A/CT diagenetic barrier. Our model suggests that in low magma input regions sills emplace at constant depth from the seafloor, while high magma input leads to upward stacking of sills, culminating in a funnel‐shaped intrusions. Our petrophysical, petrographic, and textural analyses show that magma‐sediment mingling creates significant porosity (up to 20%) through thermal cracking of the assimilated sediment. Stable isotope data suggest carbonate formation at 70–90°C, consistent with background geothermal gradient at 250–325 m depth. The unconsolidated, water‐rich host sediments produce little thermogenic gas through contact metamorphism, but deep diagenetically formed gas bypasses the low‐permeability top sediments via hydrothermal fluids flowing through the magma plumbing system. This hydrothermal system provides a steady supply of hydrocarbons at temperatures amendable for microbial life, serving as an incubator that may be abundant in magma‐rich young rift basins and play a key role in sustaining subseafloor ecosystems.

Authors

Institutions

Publication Details

Journal
Journal of Geophysical Research Solid Earth
Published
2025-03-01
DOI
https://doi.org/10.1029/2024jb030354
Citations
4
Primary Topic
Geological and Geochemical Analysis
Type
article
Field-Weighted Citation Impact
11.20

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Sill Stacking in Subseafloor Unconsolidated Sediments and Control on Sustained Hydrothermal Systems: Evidence From IODP Drilling in the Guaymas Basin, Gulf of California

Christoph Böttner, Henning Kuhnert, Christophe Y. Galerne, Kathleen M. Marsaglia et al.
4 citations
Journal of Geophysical Research Solid Earth
Geological and Geochemical Analysis
11.20
article

Sill Stacking in Subseafloor Unconsolidated Sediments and Control on Sustained Hydrothermal Systems: Evidence From IODP Drilling in the Guaymas Basin, Gulf of California

Christoph Böttner, Henning Kuhnert, Christophe Y. Galerne, Kathleen M. Marsaglia, Tobias W. Höfig, Joann M. Stock, Achim Kopf, Daniel Lizarralde, Christian Berndt, Wolf‐Achim Kahl, Raquel Negrete‐Aranda, Alban Cheviet, Wolfgang Bach, Ivano W. Aiello, Swanne Gontharet, Andreas Teske, Jens Karstens, Martine D. Buatier, Christin Wiggers, Manet E. Peña-Salinas, Florian Neumann, Junli Zhang
article en
4 citations

Abstract

Abstract Magma emplacement in the top unconsolidated sediments of rift basins is poorly understood. We compare two shallow sills from the Guaymas Basin (Gulf of California) using core data and analyses from IODP Expedition 385, and high‐resolution 2D seismic data. We show that magma stalling in the top uncemented sediment layer is controlled by the transition from siliceous claystone to uncemented silica‐rich sediment, favoring flat sill formation. Space is created through a combination of viscous indentation, magma‐sediment mingling and fluidization processes. We show that sills emplace above the opal‐A/CT diagenetic barrier. Our model suggests that in low magma input regions sills emplace at constant depth from the seafloor, while high magma input leads to upward stacking of sills, culminating in a funnel‐shaped intrusions. Our petrophysical, petrographic, and textural analyses show that magma‐sediment mingling creates significant porosity (up to 20%) through thermal cracking of the assimilated sediment. Stable isotope data suggest carbonate formation at 70–90°C, consistent with background geothermal gradient at 250–325 m depth. The unconsolidated, water‐rich host sediments produce little thermogenic gas through contact metamorphism, but deep diagenetically formed gas bypasses the low‐permeability top sediments via hydrothermal fluids flowing through the magma plumbing system. This hydrothermal system provides a steady supply of hydrocarbons at temperatures amendable for microbial life, serving as an incubator that may be abundant in magma‐rich young rift basins and play a key role in sustaining subseafloor ecosystems.

Journal of Geophysical Research Solid EarthVol. 130(3)
University of North Carolina at Chapel Hill (US), California Institute of Technology (US), Centre National de la Recherche Scientifique (FR), California State University, Northridge (US), Universidad Autónoma de Baja California (MX), University of Bremen (DE), Aarhus University (DK), GEOMAR Helmholtz Centre for Ocean Research Kiel (DE), Sorbonne Université (FR), GFZ Helmholtz Centre for Geosciences (DE), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (FR), Institut de Recherche pour le Développement (FR), Centro de Investigación Científica y de Educación Superior de Ensenada (MX), Woods Hole Oceanographic Institution (US), Moss Landing Marine Laboratories (US)
Discovery Eye Foundation, Deutsche Forschungsgemeinschaft
Life below water
Openalex Percentile: Top 1%
Geological and Geochemical Analysis
11.20
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.