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GEOREF RECORD

Basin formation by volcanic arc loading

Dave Waltham, Robert Hall, Helen R. Smyth and Cynthia J. Ebinger
Basin formation by volcanic arc loading (in Formation and applications of the sedimentary record in arc collision zones, Amy E. Draut (editor), Peter D. Clift (editor) and David W. Scholl (editor))
Special Paper - Geological Society of America (2008) 436: 11-26

Abstract

This paper quantifies the flexural subsidence expected from loading by a volcanic arc. The resulting mathematical model shows that the arc width should grow with time and that the subsidence beneath the load can be estimated from the observed arc width at the surface. Application of this model to the Halmahera Arc in Indonesia shows an excellent fit to observations if a broken-plate model of flexure is assumed. The model also gives an excellent fit to data from East Java, also in Indonesia, where it is possible to forward model gravity anomalies. In particular, the depth, location, and width of the depocenter-associated gravity low are accurately reproduced, although the model does require a high density for the volcanic arc (2900 kg m (super -3) ). This may indicate additional buried loads due, for example, to magmatic underplating. Our main conclusion is that loads generated by the volcanic arc are sufficient to account for much, if not all, of the subsidence in basins within approximately 100 km of active volcanoes at subduction plate boundaries, if the plate is broken. The basins will be asymmetrical and, close to the arc, will contain coarse volcaniclastic material, whereas deposits farther away are likely to be volcaniclastic turbidites. The density contrast between arc and underlying crust required to produce the Indonesian arc basins means that they are unlikely to form in young intraoceanic arcs but may be common in older and more mature arcs.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 436
Title: Basin formation by volcanic arc loading
Title: Formation and applications of the sedimentary record in arc collision zones
Author(s): Waltham, DaveHall, RobertSmyth, Helen R.Ebinger, Cynthia J.
Author(s): Draut, Amy E.editor
Author(s): Clift, Peter D.editor
Author(s): Scholl, David W.editor
Affiliation: Royal Holloway University of London, Department of Geology, Surrey, United Kingdom
Affiliation: U. S. Geological Survey, Santa Cruz, CA, United States
Pages: 11-26
Published: 2008
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 42
Accession Number: 2008-111754
Categories: Solid-earth geophysicsApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., 2 tables, sketch maps
S02°00'00" - N02°00'00", E124°00'00" - E130°00'00"
Secondary Affiliation: University of Aberdeen, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200841
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