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Hydrothermal Exploration of the southern Chile Rise: Sediment-hosted venting at the Chile Triple Junction.
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  • Christopher R German,
  • Tamara Baumberger,
  • Marvin D. Lilley,
  • John Edward Lupton,
  • Abigail E. Noble,
  • Mak A. Saito,
  • Andrew Thurber,
  • Donna K Blackman
Christopher R German
Wood Hole Oceanographic Institution

Corresponding Author:[email protected]

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Tamara Baumberger
Cooperative Institute for Marine Resources Studies, Oregon State University
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Marvin D. Lilley
School of Oceanography, University of Washington
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John Edward Lupton
NOAA-PMEL
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Abigail E. Noble
Woods Hole Oceanographic Institution
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Mak A. Saito
WHOI
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Andrew Thurber
College of Ocean Earth, Ocean & Atmospheric Sciences, Oregon State University
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Donna K Blackman
University of California, Santa Cruz
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Abstract

We report results from a hydrothermal plume survey along the southernmost Chile Rise from the Guamblin Fracture Zone to the Chile Triple Junction encompassing two segments (93km cumulative length) of intermediate spreading-rate mid-ocean ridge axis. Our approach used in situ water column sensing (CTD, optical clarity, redox disequilibrium) coupled with sampling for shipboard and shore based geochemical analyses (d3He, CH4, TDFe, TDMn) to explore for evidence of seafloor hydrothermal venting. Across the entire survey, the only location at which evidence for submarine venting was detected was at the southernmost limit to the survey. There, the source of a dispersing hydrothermal plume was located at 46°16.5’S, 75°47.9’W, coincident with the Chile Triple Junction itself. The plume exhibits anomalies in both d3He and dissolved CH4 but no enrichments in TDFe or TDMn beyond what can be attributed to resuspension of sediments covering the seafloor where the ridge intersects the Chile margin. From comparison with the Escanaba Trough on the southern Gorda Ridge, we infer that the anomalies we report here arise from sediment-hosted venting at the Chile Triple Junction.
Mar 2022Published in Geochemistry, Geophysics, Geosystems volume 23 issue 3. 10.1029/2021GC010317