Formation of Acid Volcanic Brines through Interaction of Magmatic Gases, Seawater, and Rock within the White Island Volcanic-Hydrothermal System, New Zealand

2005 ◽  
pp. 19-40
Keyword(s):  
New Zealand ◽  
Hydrothermal System ◽  
Acid Volcanic ◽  
Magmatic Gases ◽  
White Island

scholarly journals Modeling of Volcano-hydrothermal System of White Island Volcano, New Zealand

2005 ◽  
Vol 114 (6) ◽  
pp. 1044-1047
Author(s):  
Yuji NISHI ◽  
Nobuo MATSUSHIMA ◽  
Tsuneo ISHIDO
Keyword(s):  
New Zealand ◽  
Hydrothermal System ◽  
White Island

Research drilling into the volcanic hydrothermal system on White Island, New Zealand

Eos ◽  
1989 ◽  
Vol 70 (7) ◽  
pp. 98 ◽  
Author(s):  
Werner F. Giggenbach ◽  
Jeffrey W. Hendenquist ◽  
Bruce F. Houghton ◽  
Peter M. Otway ◽  
Richard G. Allis
Keyword(s):  
New Zealand ◽  
Hydrothermal System ◽  
White Island

scholarly journals Volatile transport of metals in the andesitic magmatic-hydrothermal system of White Island

2021 ◽  
Author(s):  
◽  
Céline Mandon
Keyword(s):  
Hydrothermal System ◽  
Crater Lake ◽  
Magma Mixing ◽  
Aqueous Fluid ◽  
Metal Mobility ◽  
Volcanic Plume ◽  
Volcanic Gases ◽  
Volatile Transport ◽  
Magmatic Gases ◽  
White Island

<p>Volcanic gases observed at active volcanoes originate from the magma at depth. These volatiles exsolve as a result of decompression, crystallization and cooling of the silicate melt. The transport of metals in a magmatic volatile phase arises from complexation with the main volatile species, sulfur and halides. Composition of the magma, temperature, pressure and redox state have thus strong implications on metal mobility in these environments. Moreover, a variety of interactions and phase separations can affect these fluids after exsolution from the parental magma. This thesis aims at constraining the volatile transport of trace metals at White Island, a subduction-related magmatic-hydrothermal system, through a characterization and metal budget of the magmatic reservoir and the different atmospheric discharges.  The metal content of the reservoir, as well as the effects of degassing and magma mixing on the magma are explored through the study of ejecta from the 1976-2000 eruptive cycle. CO₂, SO₂ and H₂O are degassing from a mafic melt at ~ 5 km depth, regularly feeding a shallower and evolved reservoir at ~ 800 m. Average contents of 164 ppm of Cu, 73 ppm of Zn, 12 ppm of Pb and 0.4 ppm of Au and Ag were detected in melt inclusions. A fraction of these metals partition into the exsolving aqueous fluid. Onset of magnetite crystallization may trigger exsolution of sulphide melt, found to contain around 30 wt% of Cu, and as much as 36 wt% Ni, 21 wt% Ag, 0.10 wt% Au in small inclusions, representing a considerable source of metals available for an aqueous fluid phase upon resorption.  The volatile transport of metals is indicated by their enrichment in a variety of discharges at the surface. The hyperacidic waters of the crater lake absorb metals from the magmatic gases injected at subaqueous vents. Concentrations of ~ 12 ppm of As and Zn, 6 ppm of Cu and Pb were observed. Hydrolysis of the host rock by the reactive waters is responsible for the high cation contents of the fluids. Precipitation of secondary minerals such as silica, anhydrite, gypsum, sulfur and alunite occurs within and underneath the crater lake. The predicted speciation of metals greatly varies, dominated by CuI and FeII chloride complexes in the more reduced environment at the lake bottom, whereas CuII and FeIII are stable in the oxidized surficial waters. Arsenic is mainly present as As(OH)₃ at depth, with H₃AsO₄ dominating at the surface. Ag, Pb and Zn are complexed with chloride, and are not redox dependent. The presence of a body of molten sulfur at the bottom of the lake is indicated by sulfur spherules, both floating at the lake surface and in sediments. Pyrite crystals coat the surface of some globules, and chemical analyses reveal an enrichment in a variety of chalcophile metals (Tl, Sb, Bi, Au, As, Ag. Re, Cu).  The volcanic gases emitted at fumaroles are enriched in metals compared to the magma. The effective transport of Se, Te, Sb, B, Au, As, and Bi is indicated by enrichment factors larger than 1000. In contrast, Cu is relatively depleted, suggesting deposition in the subsurface environment. Variations in composition are observed with time, mainly depending on temperature and major composition of the emissions. Values > 100 ppb of Sb, Bi, Ni, Zn, As and Se, > 10 ppb of Te, Pb, and Cu, and up to 8 ppb of Tl were recorded. Chloride is predicted to be the main ligand responsible for metal transport, even at higher temperature. The lack of thermodynamic data for complex solvated metal clusters may nevertheless bias our results. The low temperature of the studied fumaroles (maximum 192.5 °C) is in accordance with the small abundance of sulfides in the sublimates, whereas the high proportion of sulfates indicates oxidized conditions.  The volcanic plume is enriched in metals such as Bi, Cd, Tl, Se, Te and Sb. The most common particles emitted are sulfates, halides, silicates, sulphuric acid and Zn ± Cu oxides. Metal emission rates are in the range of 1-10 kg/day for As, Se, Cu and Zn, 0.1-1 kg/day for Pb, Tl and Bi. Emissions of high-temperature magmatic gases are indicated by elevated SO₂/HCl ratio and the presence of Au in the particulate phase.  Mass balance calculations in White Island magmatic-hydrothermal system indicate a segregation of around 4900 tons of copper per year, either accumulated from a dense brine at ~ 500 m depth, or deposited by low-density vapors on their way to the surface. Metal-rich sulfide blebs trapped in phenocrysts may also retain Cu at depth. These results thus reinforce the belief that White Island is an actively forming porphyry copper deposit.</p>

scholarly journals Mechanical behaviour and failure modes in the Whakaari (White Island volcano) hydrothermal system, New Zealand

2015 ◽  
Vol 295 ◽  
pp. 26-42 ◽  
Author(s):  
Michael J. Heap ◽  
Ben M. Kennedy ◽  
Noémie Pernin ◽  
Laura Jacquemard ◽  
Patrick Baud ◽  
...  
Keyword(s):  
New Zealand ◽  
Mechanical Behaviour ◽  
Hydrothermal System ◽  
Failure Modes ◽  
White Island

scholarly journals White Island: a sulphur-rich hydrothermal system

2004 ◽  
Vol 25 (1) ◽  
pp. 28 ◽  
Author(s):  
Philip Butterworth
Keyword(s):  
New Zealand ◽  
Hydrothermal System ◽  
Terrestrial Ecosystems ◽  
Active Volcano ◽  
Hydrothermal Environment ◽  
White Island

White Island (Whakaari) is New Zealand?s most active volcano. The sulphur-rich hydrothermal environment of the island is considered an analogue for early terrestrial ecosystems that supported sulphur-metabolising microorganisms.

scholarly journals Modeling of Volcano-hydrothermal System of White Island Volcano, New Zealand

2005 ◽  
Vol 114 (6) ◽  
pp. Plate5-Plate5
Author(s):  
Yuji NISHI ◽  
Nobuo MATSUSHIMA ◽  
Tsuneo ISHIDO
Keyword(s):  
New Zealand ◽  
Hydrothermal System ◽  
White Island

White Island, New Zealand, volcanic-hydrothermal system represents the geochemical environment of high-sulfidation Cu and Au ore deposition

Geology ◽  
1993 ◽  
Vol 21 (8) ◽  
pp. 731 ◽  
Author(s):  
Jeffrey W. Hedenquist ◽  
Stuart F. Simmons ◽  
Werner F. Giggenbach ◽  
C. Stewart Eldridge
Keyword(s):  
New Zealand ◽  
Hydrothermal System ◽  
Geochemical Environment ◽  
High Sulfidation ◽  
Ore Deposition ◽  
White Island
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