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Widespread seawater circulation in 18–22 Ma oceanic crust: Impact on heat flow and sediment geochemistry

2017; Geological Society of America; Volume: 45; Issue: 9 Linguagem: Inglês

10.1130/g39091.1

1943-2682

Thomas Kuhn, Gerard J M Versteegh, Heinrich Villinger, Ingrid Dohrmann, Christina Heller, Andrea Koschinsky, Norbert E Kaul, Simon Ritter, Anna V. Wegorzewski, Sabine Kasten,

Hydrocarbon exploration and reservoir analysis

Research Article| June 29, 2017 Widespread seawater circulation in 18–22 Ma oceanic crust: Impact on heat flow and sediment geochemistry Thomas Kuhn; Thomas Kuhn 1Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Germany Search for other works by this author on: GSW Google Scholar G.J.M. Versteegh; G.J.M. Versteegh 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany Search for other works by this author on: GSW Google Scholar H. Villinger; H. Villinger 3Department of Geosciences, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany Search for other works by this author on: GSW Google Scholar I. Dohrmann; I. Dohrmann 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany Search for other works by this author on: GSW Google Scholar C. Heller; C. Heller 1Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Germany Search for other works by this author on: GSW Google Scholar A. Koschinsky; A. Koschinsky 4Department of Physics & Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany Search for other works by this author on: GSW Google Scholar N. Kaul; N. Kaul 3Department of Geosciences, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany Search for other works by this author on: GSW Google Scholar S. Ritter; S. Ritter 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany5Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany Search for other works by this author on: GSW Google Scholar A.V. Wegorzewski; A.V. Wegorzewski 1Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Germany Search for other works by this author on: GSW Google Scholar S. Kasten S. Kasten 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information Thomas Kuhn 1Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Germany G.J.M. Versteegh 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany H. Villinger 3Department of Geosciences, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany I. Dohrmann 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany C. Heller 1Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Germany A. Koschinsky 4Department of Physics & Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany N. Kaul 3Department of Geosciences, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany S. Ritter 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany5Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany A.V. Wegorzewski 1Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Germany S. Kasten 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, D-27570 Bremerhaven, Germany Publisher: Geological Society of America Received: 23 Feb 2017 Revision Received: 04 May 2017 Accepted: 04 May 2017 First Online: 29 Jun 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2017 Geological Society of America Geology (2017) 45 (9): 799–802. https://doi.org/10.1130/G39091.1 Article history Received: 23 Feb 2017 Revision Received: 04 May 2017 Accepted: 04 May 2017 First Online: 29 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Thomas Kuhn, G.J.M. Versteegh, H. Villinger, I. Dohrmann, C. Heller, A. Koschinsky, N. Kaul, S. Ritter, A.V. Wegorzewski, S. Kasten; Widespread seawater circulation in 18–22 Ma oceanic crust: Impact on heat flow and sediment geochemistry. Geology 2017;; 45 (9): 799–802. doi: https://doi.org/10.1130/G39091.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract On the basis of heat-flow measurements, seismic mapping, and sediment pore-water analysis, we demonstrate widespread and efficient ventilation of the 18–22 Ma oceanic crust of the northeast equatorial Pacific Ocean. Recharge and discharge appear to be associated with basement outcrops, including seamounts and north-south–trending faults, along which sediment cover thins out and volcanic rocks are exposed. Low-temperature hydrothermal circulation through the volcanic crust leads to the reduction of heat flow through overlying sediments, with measured heat-flow values that are well below those expected from conductive cooling curves for lithosphere of this age. Typically, dissolved pore-water oxygen decreases from the sediment surface downward, reaching minimum values at mid-depth and rising again in the lower part of the cores investigated, clearly indicating oxygen-rich seawater circulation through the oceanic crust underneath the sediments. If the residence time of the circulating fluids in the upper crust is short or the fluid flux is large, oxic conditions may be preserved, and oxygen can diffuse upwards into the sediments. This process, leading to widespread oxic conditions in the near-basement sediments, may cause the oxidation of residual reduced material stored in the deeper sediments, resulting in downward fluxes of the reaction products into the basement and from there back into the oceans. Considering the widespread existence of this type of off-axis ventilation, the net effect of the resulting return flow of reaction products on biogeochemical cycles and element fluxes (e.g., carbon and nitrogen) may be very large. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.