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Active tectonics of the South Chilean marine fore arc (35°S–40°S)

Active tectonics of the South Chilean marine fore arc (35°S–40°S)
Active tectonics of the South Chilean marine fore arc (35°S–40°S)
The South Chilean marine fore arc (35°S–40°S) is separated into four tectonic segments, Concepción North, Concepción South, Nahuelbuta, and Tolten (from north to south). These are each characterized by their individual tectonic geomorphology and reflect different ways of mechanical and kinematic interaction of the convergent Nazca and South American plates. Splay faults that cut through continental framework rock are seismically imaged in both Concepción segments and the Tolten Segment. Additionally, the Concepción South Segment exhibits prominent upper plate normal faults. Normal faults apparently relate to uplift caused by sediment underthrusting at depth. This has led to oversteepening and gravitational collapse of the marine fore arc. There is also evidence for sediment underthrusting and basal accretion to the overriding plate in the Tolten Segment. There, uplift of the continental slope has created a landward inclined seafloor over a latitudinal distance of 50 km. In the Nahuelbuta Segment transpressive upper plate faults, aligned oblique to the direction of plate motion, control the seafloor morphology. Based on a unique acoustic data set including >90% of bathymetric coverage of the continental slope we are able to reveal an along-strike heterogeneity of a complexly deformed marine fore arc which had escaped attention in previous studies that only considered the structure along transects normal to the plate margin.
0278-7407
TC3006
Geersen, Jacob
abcf5f76-3608-4322-ab54-7bfb8dfcaf2d
Behrmann, Jan H.
7061b9f7-3ff3-438d-9fa8-19fa5163ec0d
Völker, David
f2b8a74f-9346-407a-8129-a90140ee5d3a
Krastel, Sebastian
4d9bf243-610a-4875-8c03-cd975c9f8542
Ranero, César R.
c01a0a46-de98-4439-890d-915f8291cad9
Diaz-Naveas, Juan
9dbeebdf-0191-4af3-b5c2-f5a14c0b092d
Weinrebe, Wilhelm
a3e00ec0-efa5-41c7-b3e8-ed22c627bac8
Geersen, Jacob
abcf5f76-3608-4322-ab54-7bfb8dfcaf2d
Behrmann, Jan H.
7061b9f7-3ff3-438d-9fa8-19fa5163ec0d
Völker, David
f2b8a74f-9346-407a-8129-a90140ee5d3a
Krastel, Sebastian
4d9bf243-610a-4875-8c03-cd975c9f8542
Ranero, César R.
c01a0a46-de98-4439-890d-915f8291cad9
Diaz-Naveas, Juan
9dbeebdf-0191-4af3-b5c2-f5a14c0b092d
Weinrebe, Wilhelm
a3e00ec0-efa5-41c7-b3e8-ed22c627bac8

Geersen, Jacob, Behrmann, Jan H., Völker, David, Krastel, Sebastian, Ranero, César R., Diaz-Naveas, Juan and Weinrebe, Wilhelm (2011) Active tectonics of the South Chilean marine fore arc (35°S–40°S). Tectonics, 30 (3), TC3006. (doi:10.1029/2010TC002777).

Record type: Article

Abstract

The South Chilean marine fore arc (35°S–40°S) is separated into four tectonic segments, Concepción North, Concepción South, Nahuelbuta, and Tolten (from north to south). These are each characterized by their individual tectonic geomorphology and reflect different ways of mechanical and kinematic interaction of the convergent Nazca and South American plates. Splay faults that cut through continental framework rock are seismically imaged in both Concepción segments and the Tolten Segment. Additionally, the Concepción South Segment exhibits prominent upper plate normal faults. Normal faults apparently relate to uplift caused by sediment underthrusting at depth. This has led to oversteepening and gravitational collapse of the marine fore arc. There is also evidence for sediment underthrusting and basal accretion to the overriding plate in the Tolten Segment. There, uplift of the continental slope has created a landward inclined seafloor over a latitudinal distance of 50 km. In the Nahuelbuta Segment transpressive upper plate faults, aligned oblique to the direction of plate motion, control the seafloor morphology. Based on a unique acoustic data set including >90% of bathymetric coverage of the continental slope we are able to reveal an along-strike heterogeneity of a complexly deformed marine fore arc which had escaped attention in previous studies that only considered the structure along transects normal to the plate margin.

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Published date: 2011
Organisations: Geology & Geophysics

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Local EPrints ID: 338737
URI: http://eprints.soton.ac.uk/id/eprint/338737
ISSN: 0278-7407
PURE UUID: 8b4b9cfe-69f6-4b38-9846-ba6dbb2c2f26

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Date deposited: 15 May 2012 13:20
Last modified: 14 Mar 2024 11:04

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Contributors

Author: Jacob Geersen
Author: Jan H. Behrmann
Author: David Völker
Author: Sebastian Krastel
Author: César R. Ranero
Author: Juan Diaz-Naveas
Author: Wilhelm Weinrebe

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