Lyell Collection
Journal of the Geological Society
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
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 Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by BUTLER, I. B.
Right arrow Articles by NESBITT, R. W.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Journal of the Geological Society; 1998; v. 155; issue.5; p. 773-785;
DOI: 10.1144/gsjgs.155.5.0773
© 1998 Geological Society of London

Article

Mineralogy, sulphur isotope geochemistry and the development of sulphide structures at the Broken Spur hydrothermal vent site, 29°10’N, Mid-Atlantic Ridge

I. B. BUTLER1,*, A. E. FALLICK2 & R. W. NESBITT1

1 Department of Geology, Southampton Oceanography Centre, University of Southampton, Empress Dock, European Way, Southampton SO14 3ZH, UK
2 Isotope Geosciences Unit, Scottish Universities Research and Reactor Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF, UK

A large collection of hydrothermal sulphides from the Broken Spur hydrothermal vent site, including representative samples of mound sulphide materials, has been characterized using optical mineralogy and sulphur isotope analysis. Young mound sulphides from Broken Spur have a pyrrhotite-dominated mineralogy unusual for bare ridge vent systems. However, pyrrhotite is metastable and is ultimately converted to iron disulphides. Mature sulphides are indurated, recrystallized and contain abundant quartz. Sulphide mound materials are developed by three major processes: (i) coalescing of chimney structures; (ii) accumulation of talus from mass wasting and (iii) precipitation and growth in response to hydrothermal flow. Progressive maturation of mound materials is by modification of primary textures, development of mineralogical zoning and replacement of metastable phases. Sulphur isotope analysis of 35 mineral separates returned {delta}34S values of – 0.5 to +3.2{per thousand}. These values are similar to those previously measured for Broken Spur and Snakepit, but are distinctly 32S enriched compared to the TAG active mound and some Pacific sites. Seawater entrainment and sulphate reduction within the subsurface feeder zone below Broken Spur mounds do not appear to be important processes at Broken Spur, in contrast to the TAG active mound.

Key Words: Mid-Atlantic Ridge • sulphides • sulphur • isotopes • hydrothermal vents




This article has been cited by other articles:


Home page
 Economic GeologyHome page
R. H. Sillitoe, R. H. Sillitoe, and D. R. Burrows
NEW FIELD EVIDENCE BEARING ON THE ORIGIN OF THE EL LACO MAGNETITE DEPOSIT, NORTHERN CHILE
Economic Geology, 2002; 97: 1101 - 1109.
[Abstract] [Full Text] [PDF]

Home page
 Reviews in Mineralogy and GeochemistryHome page
W. C. Shanks and W. C. Shanks III
Stable Isotopes in Seafloor Hydrothermal Systems: Vent fluids, hydrothermal deposits, hydrothermal alteration, and microbial processes
Reviews in Mineralogy and Geochemistry, 2001; 43: 469 - 525.
[Full Text] [PDF]