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Volcanic evolution of the South Sandwich volcanic arc, South Atlantic, from multibeam bathymetry
Citation
Leat, PT and Day, SJ and Tate, AJ and Martin, TJ and Owen, MJ and Tappin, DR, Volcanic evolution of the South Sandwich volcanic arc, South Atlantic, from multibeam bathymetry, Journal of Volcanology and Geothermal Research, 265 pp. 60-77. ISSN 0377-0273 (2013) [Refereed Article]
Copyright Statement
Copyright 2013 Elsevier B.V.
DOI: doi:10.1016/j.jvolgeores.2013.08.013
Abstract
New multibeam bathymetry data are presented for the South Sandwich intra-oceanic arc which occupies the
small Sandwich plate in the South Atlantic, and is widely considered to be a simple end-member in the range
of intra-oceanic arc types. The images show for the first time the distribution of submarine volcanic, tectonic
and erosional–depositional features along the whole length of the 540 km long volcanic arc, allowing systematic
investigation of along-arc variations. The data confirm that the volcanic arc has a simple structure composed of
large volcanoes which form a well-defined volcanic front, but with three parallel cross-cutting seamount chains
extending 38–60 km from near the volcanic front into the rear-arc. There is no evidence for intra-arc rifting or
extinct volcanic lines. Topographic evidence for faulting is generally absent, except near the northern and southern
plate boundaries.Most of the volcanic arc appears to be built on ocean crust formed at the associated back-arc
spreading centre, as previously proposed from magnetic data, but the southern part of the arc appears to be underlain
by older arc or continental crust whose west-facing rifted margin facing the back-arc basin is defined by
the new bathymetry. The new survey shows nine main volcanic edifices along the volcanic front and ca. 20 main
seamounts. The main volcanoes form largely glaciated islands with summits 3.0–3.5 km above base levels which
are 2500–3000 m deep in the north and shallower at 2000–2500 m deep in the south. Some of the component
seamounts are interpreted to have been active since the last glacial maximum, and so are approximately contemporaneous
with the volcanic front volcanism. Seven calderas, all either submarine or ice-filled, have been identified:
Adventure volcano, a newly discovered submarine volcanic front caldera volcano is described for the first
time. All but one of the calderas are situated on summits of large volcanoes in the southern part of the arc, and
most are associated with current or historic volcanic or hydrothermal activity. Shallow shelves around the islands
are generally 1–10 km wide. Submerged banks up to 1100 m deep are interpreted as subsided erosional surfaces.
Seamounts and emergent volcanoes experienced a range of mass wasting processes including by landsliding and
smaller mass flows.
Item Details
Item Type: | Refereed Article |
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Keywords: | volcanic arc, subduction zone, Caldera Seamount, submarine volcanism |
Research Division: | Earth Sciences |
Research Group: | Geology |
Research Field: | Volcanology |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the earth sciences |
ID Code: | 119348 |
Year Published: | 2013 |
Web of Science® Times Cited: | 28 |
Deposited By: | Oceans and Cryosphere |
Deposited On: | 2017-07-31 |
Last Modified: | 2017-09-28 |
Downloads: | 0 |
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