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Rolling open Earth's deepest forearc basin

Jonathan M. Pownall, Robert Hall and Gordon S. Lister
Rolling open Earth's deepest forearc basin
Geology (Boulder) (September 2016) 44 (11): 947-950


The Weber Deep-a 7.2-km-deep forearc basin within the tightly curved Banda arc of eastern Indonesia-is the deepest point of the Earth's oceans not within a trench. Several models have been proposed to explain the tectonic evolution of the Banda arc in the context of the ongoing (ca. 23 Ma-present) Australia-Southeast Asia collision, but no model explicitly accounts for how the Weber Deep achieved its anomalous depth. Here we propose that the Weber Deep formed by forearc extension driven by eastward subduction rollback. Substantial lithospheric extension in the upper plate was accommodated by a major, previously unidentified, low-angle normal fault system we name the "Banda detachment." High-resolution bathymetry data reveal that the Banda detachment is exposed underwater over much of its 120 km down-dip and 450 km lateral extent, having produced the largest bathymetric expression of any fault discernable in the world's oceans. The Banda arc is a modern analogue for highly extended terranes preserved in the many regions that may similarly have "rolled open" behind migrating subduction zones.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 44
Serial Issue: 11
Title: Rolling open Earth's deepest forearc basin
Affiliation: Australian National University, Research School of Earth Sciences, Canberra, A.C.T., Australia
Pages: 947-950
Published: 20160928
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 34
Accession Number: 2016-094407
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2016324
Illustration Description: illus. incl. sect., geol. sketch map
S04°00'00" - S03°00'00", E130°00'00" - E131°00'00"
Secondary Affiliation: Royal Holloway-University of London, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201646
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