TY - JOUR
T1 - Fluxes and sources of volatiles discharged from kudryavy, a subduction zone volcano, Kurile Islands
AU - Fischer, Tobias P.
AU - Giggenbach, Werner F.
AU - Sano, Yuji
AU - Williams, Stanley
N1 - Funding Information:
We are honored to have finished this paper with a close friend, whom we have admired for many years. Werner was the scientist who set an example for all of us to remember. He was the classical outstanding scientist who collected and analyzed all his samples himself and then tested the results against rigorous physical and chemical methods and theories. Always enthusiastic, yet critical, sarcastic with a great sense of humor, he pushed himself and others to do better work. We feel great sympathy for his family who lost a husband, father and grandfather. We want to thank our Russian colleagues, especially Michael Korzinsky, Kiril Smulovich, and Genrich Steinberg for excellent logistic support and generous help during sample collection, Graham Lyons, IGNS, New Zealand, for providing the C-isotopic analyses, Bruce Christenson for help with some of the gas analyses at IGNS and Sue Selkirk at ASU for help with figures. This work was supported by a grant from NSF International Programs (SNW and TPF), a NASA Earth Systems Science Fellowship (TPF), and Arizona State University with funds for a gas chromatography laboratory. Patrick Allard, Terry Plank and an anonymous reviewer are acknowledged for thorough reviews and very helpful comments. [CL]
PY - 1998/7
Y1 - 1998/7
N2 - The Kudryavy volcano, a 996m high basaltic-andesite cone on the northeastern shore of Iturup Island in the Kuriles, erupted last in 1883 and has since been in a persistent state of high-temperature, >900°C fumarolic activity. Its flux of SO2, measured by COSPEC, is 73±15 t/d, or 416 Mmol/a. In combination with the chemical composition of the parent gas supplying the high-temperature vents and the isotopic compositions of He and C, it allows the evaluation of contributions from major source components, such as the mantle, the crust, and subducted sediments and carbonate. The 3He/4He ratio of 6.7 RA corresponds to a 84% mantle origin and a flux of 2200 mol/a of mantle He. At a He concentration of 2200 mol/Mt, the mass of mantle material required to generate this flux is 1.0 Mt/a. The same mass produces a flux of 0.025 mol/a of 3He and of 50 Mmol/a of mantle CO2 at a CO2/3He ratio of 2.109. In conjunction with the C-isotopic composition of fumarolic CO2 of -7.2‰, about 12% of the CO2 are derived from the mantle, 67% from marine carbonate is subducted, altered ocenic crust, 21% are of subducted organic sedimentary origin. The flux of 280 Mmol/a of carbonate-derived CO2 requires 0.41 Mt/a of oceanic crust with a CO2 content of 3 wt%, and 0.35 Mt/a of sedimentary material to supply the organic CO2 flux of 86 Mmol/a. Nitrogen from the mantle contributes at most 2% to the total N2 flux of 5.4 Mmol/a. Assuming N to be derived from the subducted sediments, its concentration there is 460 mg/kg. The total volume of mantle and subducted material required to maintain the flux of volatiles over the 100 a period of high-temperature fumarolic activity of Kudryavy is 0.07 km3. Steady-state release of volatiles from the depth of arc magma generation to the fumaroles and continuously high heat flow from the mantle are proposed as the main process supporting the long-term high-temperature degassing at Kudryavy. In this steady-state system, the calculated volatle fluxes are balanced over time by volatiles originating from subducted sediments, hydrothermally altered ocean crust below the Kudryavy volcano and the mantle wedge. This has significantly implications for volatile cycling from the Earth's crust and mantle to the atmosphere.
AB - The Kudryavy volcano, a 996m high basaltic-andesite cone on the northeastern shore of Iturup Island in the Kuriles, erupted last in 1883 and has since been in a persistent state of high-temperature, >900°C fumarolic activity. Its flux of SO2, measured by COSPEC, is 73±15 t/d, or 416 Mmol/a. In combination with the chemical composition of the parent gas supplying the high-temperature vents and the isotopic compositions of He and C, it allows the evaluation of contributions from major source components, such as the mantle, the crust, and subducted sediments and carbonate. The 3He/4He ratio of 6.7 RA corresponds to a 84% mantle origin and a flux of 2200 mol/a of mantle He. At a He concentration of 2200 mol/Mt, the mass of mantle material required to generate this flux is 1.0 Mt/a. The same mass produces a flux of 0.025 mol/a of 3He and of 50 Mmol/a of mantle CO2 at a CO2/3He ratio of 2.109. In conjunction with the C-isotopic composition of fumarolic CO2 of -7.2‰, about 12% of the CO2 are derived from the mantle, 67% from marine carbonate is subducted, altered ocenic crust, 21% are of subducted organic sedimentary origin. The flux of 280 Mmol/a of carbonate-derived CO2 requires 0.41 Mt/a of oceanic crust with a CO2 content of 3 wt%, and 0.35 Mt/a of sedimentary material to supply the organic CO2 flux of 86 Mmol/a. Nitrogen from the mantle contributes at most 2% to the total N2 flux of 5.4 Mmol/a. Assuming N to be derived from the subducted sediments, its concentration there is 460 mg/kg. The total volume of mantle and subducted material required to maintain the flux of volatiles over the 100 a period of high-temperature fumarolic activity of Kudryavy is 0.07 km3. Steady-state release of volatiles from the depth of arc magma generation to the fumaroles and continuously high heat flow from the mantle are proposed as the main process supporting the long-term high-temperature degassing at Kudryavy. In this steady-state system, the calculated volatle fluxes are balanced over time by volatiles originating from subducted sediments, hydrothermally altered ocean crust below the Kudryavy volcano and the mantle wedge. This has significantly implications for volatile cycling from the Earth's crust and mantle to the atmosphere.
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U2 - 10.1016/S0012-821X(98)00086-7
DO - 10.1016/S0012-821X(98)00086-7
M3 - Article
AN - SCOPUS:0031787649
SN - 0012-821X
VL - 160
SP - 81
EP - 96
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 1-2
ER -