Show simple item record

dc.contributor.authorVanko, David A.  Concept link
dc.contributor.authorBach, Wolfgang  Concept link
dc.contributor.authorRoberts, Stephen  Concept link
dc.contributor.authorYeats, Christopher J.  Concept link
dc.contributor.authorScott, Steven D.  Concept link
dc.date.accessioned2010-07-13T12:28:49Z
dc.date.available2010-07-13T12:28:49Z
dc.date.issued2004-03-05
dc.identifier.citationJournal of Geophysical Research 109 (2004): B03201en_US
dc.identifier.urihttps://hdl.handle.net/1912/3738
dc.descriptionAuthor Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): B03201, doi:10.1029/2003JB002579.en_US
dc.description.abstractAltered volcanic rocks were cored from over 350 m below the seafloor at the Papua New Guinea-Australia-Canada Manus Basin Hydrothermal Field (PACMANUS) deep-sea hydrothermal field, in the eastern Manus back arc basin. Fluid inclusions in anhydrite veins reveal phase separation and fluid mixing beneath the seafloor. The anhydrite precipitated from high-temperature fluids (150–385°C). At Roman Ruins, a site of active high-temperature venting (220–276°C, measured by submersible), the fluid inclusion thermal depth profile is uniform and high temperature (242–368°C). At Snowcap, a site of warm water effusion (6–65°C), the fluid inclusions indicate high temperatures at depth (270–385°C) but both low and high temperatures in the shallower section. This indicates a flow regime dominated by vertical advection and shallow entrainment and mixing with cool seawater. Inclusions at Snowcap exhibit extreme salinity variations due to phase separation at temperatures above 350°C. Fluids contain Na, Cl, Fe, Zn, Mg, and Ba and a minor gas component such as CO2 or CH4. Most inclusions at Roman Ruins exhibit salinities that fall within the range of those observed at modern active vent sites along the mid-ocean ridge system. Fluid inclusion temperatures support a hypothesis, developed previously from Sr-isotopic analysis, that the subseafloor at Snowcap is characterized by mixing between deep-sourced hot hydrothermal fluids and cold seawater-like fluid. Both heating of seawater and cooling of upwelling hydrothermal fluids can be recognized by combining isotopic and fluid inclusion data. In contrast to Snowcap, the regime at Roman Ruins is less varied, with uniformly high-temperature upwelling fluids that have hydrothermally dominated Sr-isotopic ratios.en_US
dc.description.sponsorshipW.B. and D.A.V. thank JOI/USSAC for support and S.R. acknowledges a NERC grant (NER/T/S/2000/0024).en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2003JB002579
dc.subjectFluid inclusionsen_US
dc.subjectOcean Drilling Programen_US
dc.subjectAnhydriteen_US
dc.titleFluid inclusion evidence for subsurface phase separation and variable fluid mixing regimes beneath the deep-sea PACMANUS hydrothermal field, Manus Basin back arc rift, Papua New Guineaen_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2003JB002579


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record