Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Geology Signup for GSW Email News
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Geology; January 2005; v. 33; no. 1; p. 61-64; DOI: 10.1130/G20870.1
© 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 Google Scholar
Google Scholar
Right arrow Articles by McConachy, T. F.
Right arrow Articles by Tevi, T.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

New hydrothermal activity and alkalic volcanism in the backarc Coriolis Troughs, Vanuatu

Timothy F. McConachy1, Richard J. Arculus2, Christopher J. Yeats3, Raymond A. Binns4, Fernando J.A.S. Barriga5, Brent I.A. McInnes6, Stephen Sestak6, Robina Sharpe7, Brooks Rakau8 and Tony Tevi8

1 Commonwealth Scientific and Industrial Research Organisation, Exploration and Mining, PO Box 136, North Ryde, Sydney NSW 1670, Australia
2 Department of Earth and Marine Sciences, Australian National University, Canberra ACT 0200, Australia
3 Commonwealth Scientific and Industrial Research Organisation, Exploration and Mining, PO Box 136, North Ryde, Sydney NSW 1670, Australia
4 Commonwealth Scientific and Industrial Research Organisation, Exploration and Mining, PO Box 136, North Ryde, Sydney NSW 1670, Australia, and Department of Earth and Marine Sciences, Australian National University, Canberra ACT 0200, Australia
5 Department of Geology, University of Lisbon, Edificio, Piso 5, Campo Grande, 1749-016 Lisboa, Portugal
6 Commonwealth Scientific and Industrial Research Organisation, Petroleum Resources, PO Box 136, North Ryde, Sydney NSW 1670, Australia
7 Centre for Ore Deposit Research, University of Tasmania, PO Box 252-79, Hobart, Tasmania 7001, Australia
8 Department of Geology, Mines and Water Resources, Private Mail Bag 001, Port Vila, Republic of Vanuatu

The Vanuatu Australia Vents Expedition (VAVE) to the Coriolis Troughs in southern Vanuatu during September 2001 aboard the RV Franklin discovered a new hydrothermal vent field—herein informally named Nifonea—and recent alkalic volcanic activity. The Nifonea field in the central Vate Trough was located by coincident light transmission and CH4 anomalies in a hydrothermal plume of ~60 km2 extent, best developed between 1600 and 1750 m depth at ~150 m above the seafloor. Extensive hydrothermal fauna and yellow-brown crusts and mounds cover an area of ~1 km2. Very fresh, glassy, variably vesicular, sparsely phyric and aphyric basalt, trachybasalt, and basaltic trachyandesite (with ~5– 6 wt% combined alkalies at ~51%–53% SiO2 and enriched light rare earth elements, Nb, and Zr) samples were dredged from youthful curtain, tube, and sheet flows, plus iron oxyhydroxide deposits. The alkalic composition of lavas in this tectonic setting is unique and attributed to thin ocean crust being developed in an incipient rifting phase involving a relatively low percentage of source-mantle melting. The Coriolis Troughs are among Earth's most youthful backarc basins and thus provide valuable insights to incipient rifting and hydrothermal processes.

Key Words: hydrothermal processes • backarc • trachyandesite • iron oxyhydroxides • Vanuatu






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