Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Geology Email Content Delivery
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Geology; March 2005; v. 33; no. 3; p. 213-216; DOI: 10.1130/G21317.1
© 2005 Geological Society of America
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (15)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Teichert, B. M.A.
Right arrow Articles by Bohrmann, G.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Clathrites: Archives of near-seafloor pore-fluid evolution ({delta}44/40Ca, {delta}13C, {delta}18O) in gas hydrate environments

Barbara M.A. Teichert1, Nikolaus Gussone1, Anton Eisenhauer2 and Gerhard Bohrmann3

1 Forschungszentrum Ozeanränder, Universität Bremen, Postfach 330440, D-28334 Bremen, Germany
2 Leibniz-Institut für Meereswissenschaften (IFM), GEOMAR, Dienstgebäude Ostufer, Wischhofstrasse 1-3, D-24148 Kiel, Germany
3 Forschungszentrum Ozeanränder, Universität Bremen, Postfach 330440, D-28334 Bremen, Germany

Aragonitic clathrites are methane-derived precipitates that are found at sites of massive near-seafloor gas hydrate (clathrate) accumulations at the summit of southern Hydrate Ridge, Cascadia margin. These platy carbonate precipitates form inside or in proximity to gas hydrate, which in our study site currently coexists with a fluid that is highly enriched in dissolved ions as salts are excluded during gas hydrate formation. The clathrites record the preferential incorporation of 18O into the hydrate structure and hence the enrichment of 16O in the surrounding brine. We measured {delta}18O values as high as 2.27{per thousand} relative to Peedee belemnite that correspond to a fluid composition of –1.18{per thousand} relative to standard mean ocean water. The same trend can be observed in Ca isotopes. Ongoing clathrite precipitation causes enrichment of the 44Ca in the fluid and hence in the carbonates. Carbon isotopes confirm a methane source for the carbonates. Our triple stable isotope approach that uses the three main components of carbonates (Ca, C, O) provides insight into multiple parameters influencing the isotopic composition of the pore water and hence the isotopic composition of the clathrites. This approach provides a tool to monitor the geochemical processes during clathrate and clathrite formation, thus recording the evolution of the geochemical environment of gas hydrate systems.

Key Words: clathrite • clathrate • {delta}13C • {delta}18O • {delta}44/40Ca • gas hydrate brine • aragonite • Ca isotope fractionation




This article has been cited by other articles:


Home page
 GeologyHome page
N. Gussone, G. Langer, S. Thoms, G. Nehrke, A. Eisenhauer, U. Riebesell, and G. Wefer
Cellular calcium pathways and isotope fractionation in Emiliania huxleyi
Geology, August 1, 2006; 34(8): 625 - 628.
[Abstract] [Full Text] [PDF]


JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Geological Society of America