Volcanic glasses at the Izu arc volcanic front : new perspectives on fluid and sediment melt recycling in subduction zones

View/ Open
Date
2004-01-22Author
Straub, S. M.
Concept link
Layne, Graham D.
Concept link
Schmidt, A.
Concept link
Langmuir, Charles H.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/461As published
https://doi.org/10.1029/2002GC000408DOI
10.1029/2002GC000408Abstract
Volcanic glasses contained in distal fallout tephras from the Izu arc volcanic front (Izu VF) provide unique perspectives on general problems of arc volcanism. Unlike cogenetic lavas, these glasses are liquid compositions where element concentrations as well as ratios have significance. Isotopic evidence and previous work show that there is no sediment melt contribution to the sources of the Izu VF tephras, and hence their trace element characteristics permit determination of the trace element contents of slab fluids. The slab fluid is a composite of metasediment (∼5% of total fluid) and metabasalt (∼95%) component fluids, and carries large ion lithophile elements (LILE) with high LILE/Th and LILE/U, and low Th and U relative to source. Except for Sr and K, the metabasalt fluid is much less enriched than the metasediment fluid, but its large relative proportions make it an important carrier of many trace elements. The metabasalt fluid has the characteristics of the arc trace element signature, obviating the need for ubiquitous involvement of sediment in arc magma genesis. The fluid component in the tephras is remarkably constant in composition over fifteen million years, and hence appears to be a robust composition that may be applicable to other convergent margins. Assuming that the metabasalt fluid is a common component, and that distribution coefficients between sediment and fluid are similar from one arc to another, composite fluid compositions can be estimated for other arcs. Differences from this composition then would likely result from a sediment melt component. Comparison to arcs with sediment melt components in their source (Marianas, eastern Aleutians) shows that partial sediment melts may be so enriched, that they can completely mask the signature of the comingling slab fluids. Hence sediment melts can easily dominate the trace element and isotopic signature of many convergent margins. Since sediment melts inherit the LILE/LILE ratios of the trench sediment, Earth's surface processes must eventually influence the compositional diversity of arcs.
Description
Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 5 (2004): Q01007, doi:10.1029/2002GC000408.
Collections
Suggested Citation
Article: Straub, S. M., Layne, Graham D., Schmidt, A., Langmuir, Charles H., "Volcanic glasses at the Izu arc volcanic front : new perspectives on fluid and sediment melt recycling in subduction zones", Geochemistry Geophysics Geosystems 5 (2004): Q01007, DOI:10.1029/2002GC000408, https://hdl.handle.net/1912/461Related items
Showing items related by title, author, creator and subject.
-
Crustal structure across the Costa Rican Volcanic Arc
Hayes, Jorden L.; Holbrook, W. Steven; Lizarralde, Daniel; Van Avendonk, Harm J. A.; Bullock, Andrew D.; Mora, Mauricio M.; Harder, Steven H.; Alvarado, Guillermo E.; Ramirez, Carlos J. (John Wiley & Sons, 2013-04-29)Island arcs are proposed to be essential building blocks for the crustal growth of continents; however, island arcs and continents are fundamentally different in bulk composition: mafic and felsic, respectively. The substrate ... -
Submeter bathymetric mapping of volcanic and hydrothermal features on the East Pacific Rise crest at 9°50′N
Ferrini, Vicki L.; Fornari, Daniel J.; Shank, Timothy M.; Kinsey, James C.; Tivey, Maurice A.; Soule, Samuel A.; Carbotte, Suzanne M.; Whitcomb, Louis L.; Yoerger, Dana R.; Howland, Jonathan C. (American Geophysical Union, 2007-01-19)Recent advances in underwater vehicle navigation and sonar technology now permit detailed mapping of complex seafloor bathymetry found at mid-ocean ridge crests. Imagenex 881 (675 kHz) scanning sonar data collected during ... -
Timescales of magmatic processes and eruption ages of the Nyiragongo volcanics from 238U-230Th-226Ra-210Pb disequilibria
Chakrabarti, Ramananda; Sims, Kenneth W. W.; Basu, Asish R.; Reagan, Mark K.; Durieux, Jacques (2009-09-04)The silica-undersaturated Nyiragongo volcanics, located in the East African rift, have globally unique chemical compositions and unusually low viscosities, only higher than carbonatite lavas, for terrestrial silicate ...