Titarenko, SS and McCaig, AM (2016) Modelling the Lost City hydrothermal field: influence of topography and permeability structure. Geofluids, 16 (2). pp. 314-328. ISSN 1468-8115
Abstract
The Lost City hydrothermal field (LCHF) is hosted in serpentinite at the crest of the Atlantis Massif, an oceanic core complex close to the mid-Atlantic Ridge. It is remarkable for its longevity and for venting low-temperature (40–91°C) alkaline fluids rich in hydrogen and methane. IODP Hole U1309D, 5 km north of the LCHF, penetrated 1415 m of gabbroic rocks and contains a near-conductive thermal gradient close to 100°C/km. This is remarkable so close to an active hydrothermal field. We present hydrothermal modelling using a topographic profile through the vent field and IODP site U1309. Long-lived circulation with vent temperatures similar to the LCHF can be sustained at moderate permeabilities of 10e-14 to 10e-15 m2 with a basal heatflow of 0.22 W m2. Seafloor topography is an important control, with vents tending to form and remain in higher topography. Models with a uniform permeability throughout the Massif cannot simultaneously maintain circulation at the LCHF and the near-conductive gradient in the borehole, where permeabilities <10e-16 m2 are required. A steeply dipping permeability discontinuity between the LCHF and the drill hole is required to stabilize venting at the summit of the massif by creating a lateral conductive boundary layer. The discontinuity needs to be close to the vent site, supporting previous inferences that high permeability is most likely produced by faulting related to the transform fault. Rapid increases in modelled fluid temperatures with depth beneath the vent agree with previous estimates of reaction temperature based on geochemical modelling.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015, The Authors. Published by John Wiley & Sons. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | Atlantis Massif; finite element model; fluid flow; hydrothermal; IODP Hole 1309D; Lost City; mid-Atlantic Ridge; oceanic core complex; permeability |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number NERC NE/I015035/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 02 Sep 2015 11:02 |
Last Modified: | 23 Jun 2023 21:52 |
Published Version: | https://dx.doi.org/10.1111/gfl.12151 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1111/gfl.12151 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:89323 |