Chemical and isotopic compositions of volcanic gases from the east Sunda and Banda arcs, Indonesia

Journal Article · Sun Dec 01 00:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90075-G· OSTI ID:7049718

Poorter, R P.E.; Bergen, M.J. van; Kreulen, R ^[1]; Varekamp, J C ^[2]; Poreda, R J ^[3]

---

1. Univ. of Utrecht (Netherlands)
2. Wesleyan Univ., Middletown, CT (United States)
3. Scripps Institution of Oceanography, La Jolla, CA (United States)

The easternmost Sunda Arc and the Banda Arc represent a continent-arc collision zone where magma genesis is influenced by subducted continent-derived material. Chemical and isotopic studies of volcanic gas samples from this environment provide information on the sources of volatiles in arc magmas. These volcanic gases, some of which last equilibrated at magmatic temperatures, are characterized by anomalous low {sup 3}He/{sup 4}He values, but by common arc values of C/S {approx} 2-4, {delta}{sup 13}C {approx} {minus}3{per thousand}, and {delta}{sup 34}S{sub tot} {approx} +5{per thousand}. Abundant helium and high He/Ar ratios are consistent with the subduction of terrigenous components in local sediments (or slivers of continental crust). Although individual concentration and isotope ratios of volatile components may be explicable by complex fractionation in the recycling process, the combined data are in agreement with an important role of subducted sedimentary source components. Comparison of the authors results with volcanic gas data from other arcs indicates that the carbon and sulfur signals in arc gases are relatively insensitive to the amount and nature of sediment on the subsiding plate. Hence, a contribution to arc volcanic gases from subducted altered oceanic crust cannot be excluded.

• OSTI ID: 7049718
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 55:12; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
VOLCANIC GASES
CHEMICAL COMPOSITION
ISOTOPE RATIO
ORIGIN
CARBON 13
CONTINENTAL CRUST
DEGASSING
GEOCHEMISTRY
HELIUM 3
HELIUM 4
INDONESIA
MAGMA
MAGMATISM
OCEANIC CRUST
SEDIMENTS
SUBDUCTION ZONES
SULFUR 34
VOLATILE MATTER
ASIA
CARBON ISOTOPES
CHEMISTRY
DEVELOPING COUNTRIES
EARTH CRUST
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUIDS
GASES
HELIUM ISOTOPES
ISLANDS
ISOTOPES
LIGHT NUCLEI
MATTER
NUCLEI
STABLE ISOTOPES
SULFUR ISOTOPES
580000* - Geosciences