Villar‑Muñoz, Lucía Universidad de Chile
Kinoshita, Masataka The University of Tokyo
Bento, Joaquim P. Pontificia Universidad Católica de Valparaíso
Vargas‑Cordero, Ivan Istituto Nazionale di Oceanografia e di Geofisica Sperimentale
Contreras‑Reyes, Eduardo Universidad de Chile
Tinivella, Umberta Istituto Nazionale di Oceanografia e di Geofisica Sperimentale
Giustiniani, Michela Istituto Nazionale di Oceanografia e di Geofisica Sperimentale
Abe, Natsue Japan Agency for Marine-Earth Science and Technology
Orihashi, Yuji Hirosaki University
Iwamori, Hikaru The University of Tokyo
Nishikawa, Tomoaki Kyoto University
Veloso, Eugenio Andres Andean Geothermal Center of Excellence
Haraguchi, Satoru The University of Tokyo
The Chile Triple Junction, where the hot active spreading centre of the Chile Rise system subducts beneath the South American plate, offers a unique opportunity to understand the influence of the anomalous thermal regime on an otherwise cold continental margin. Integrated analysis of various geophysical and geological datasets, such as bathymetry, heat flow measured directly by thermal probes and calculated from gas hydrate distribution limits, thermal conductivities, and piston cores, have improved the knowledge about the hydrogeological system. In addition, rock dredging has evidenced the volcanism associated with ridge subduction. Here, we argue that the localized high heat flow over the toe of the accretionary prism results from fluid advection promoted by pressure-driven discharge (i.e., dewatering/discharge caused by horizontal compression of accreted sediments) as reported previously. However, by computing the new heat flow values with legacy data in the study area, we raise the assumption that these anomalous heat flow values are also promoted by the eastern flank of the currently subducting Chile Rise. Part of the rift axis is located just below the toe of the wedge, where active deformation and vigorous fluid advection are most intense, enhanced by the proximity of the young volcanic chain. Our results provide valuable information to current and future studies related to hydrothermal circulation, seismicity, volcanism, gas hydrate stability, and fluid venting in this natural laboratory.
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