Journal of Petrology Volume 41 Number 6 Pages 867-895 2000
© Oxford University Press 2000
Magma Origin and Evolution of White Island (Whakaari) Volcano, Bay of Plenty, New Zealand
1DEPARTMENT OF GEOLOGICAL SCIENCES, UNIVERSITY OF CANTERBURY, PRIVATE BAG 4800, CHRISTCHURCH, NEW ZEALAND
2CSIRO, MAGMATIC ORE DEPOSIT GROUP, DIVISION OF MINING AND EXPLORATION, PRIVATE BAG PO WEMBLEY, 6014 W.A., AUSTRALIA
White Island is an active composite stratovolcano in the Bay of Plenty, New Zealand, that comprises many small volume (<0·1 km3) andesite–dacite lava flows and pyroclastic deposits with phenocryst contents of 
15–44%. Minor high-Mg basaltic andesite explosive eruptions, such as those of 1976–1992, may have occurred at intervals throughout the history of White Island, but are rarely preserved. These alternate with major episodes of andesite–dacite lava extrusion. The high-Mg magmas form by hydrous melting of mantle, metasomatized by fluids from the dehydrating slab at the slab–mantle wedge interface, that rise rapidly to shallow magma chambers (2–7 km?) where limited mixing and contamination occurs before eruption. Some of this magma remains in the magma chamber where it interacts with the crystal mush, from which it inherits phenocrysts, to form so-called ‘dirty’ lavas. Total phenocryst content of these lavas is correspondingly higher. As more magma is intruded into the chamber, the heat flux will increase and melt fraction will eventually rise to the surface to form high-silica andesite–dacite magma (‘clean’ lavas) with fewer inherited phenocrysts. Similar multi-magma chamber plumbing systems, with complex evolution involving fractionation and contamination, probably occur in most andesite–dacite arc volcanoes.
KEY WORDS: andesite petrogenesis; magma evolution; high-Mg magmas; Taupo Volcanic Zone; White Island
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. AUDETAT and T. PETTKE Evolution of a Porphyry-Cu Mineralized Magma System at Santa Rita, New Mexico (USA) J. Petrology, October 1, 2006; 47(10): 2021 - 2046. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. N. WILSON, S. BLAKE, B. L. A. CHARLIER, and A. N. SUTTON The 26{middle dot}5 ka Oruanui Eruption, Taupo Volcano, New Zealand: Development, Characteristics and Evacuation of a Large Rhyolitic Magma Body J. Petrology, January 1, 2006; 47(1): 35 - 69. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Agata and I. Hattori Chromite in greenstone lavas from the Kanakasu area, Nanjo Massif of the Mesozoic Mino terrane, central Japan Mineralogical Magazine, August 1, 2002; 66(4): 575 - 590. [Abstract] [Full Text] [PDF]
|
|