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

Timothy F. McConachy, Richard J. Arculus, Christopher J. Yeats, Raymond A. Binns, Fernando J. A. S. Barriga, Brent I. A. McInnes, Stephen Sestak, Robina Sharpe, Brooks Rakau and Tony Tevi
New hydrothermal activity and alkalic volcanism in the backarc Coriolis Troughs, Vanuatu
Geology (Boulder) (January 2005) 33 (1): 61-64


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 CH (sub 4) anomalies in a hydrothermal plume of approximately 60 km (super 2) extent, best developed between 1600 and 1750 m depth at approximately 150 m above the seafloor. Extensive hydrothermal fauna and yellow-brown crusts and mounds cover an area of approximately 1 km (super 2) . Very fresh, glassy, variably vesicular, sparsely phyric and aphyric basalt, trachybasalt, and basaltic trachyandesite (with approximately 5-6 wt% combined alkalies at approximately 51%-53% SiO (sub 2) 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.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 33
Serial Issue: 1
Title: New hydrothermal activity and alkalic volcanism in the backarc Coriolis Troughs, Vanuatu
Affiliation: CSIRO, Exploration and Mining, North Ryde, N.S.W., Australia
Pages: 61-64
Published: 200501
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 23
Accession Number: 2005-013960
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch maps
S18°30'00" - S18°00'00", E169°10'00" - E169°40'00"
Secondary Affiliation: Australian National University, AUS, AustraliaUniversity of Lisbon, PRT, PortugalUniversity of Tasmania, AUS, AustraliaRepublic of Vanuatu Department of Geology, Mines and Water Resources, VUT, Vanuatu
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200506
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