The University of Southampton
University of Southampton Institutional Repository

Seismic reflection images of intraplate deformation, central Indian Ocean, and their tectonic significance

Seismic reflection images of intraplate deformation, central Indian Ocean, and their tectonic significance
Seismic reflection images of intraplate deformation, central Indian Ocean, and their tectonic significance
Multichannel seismic reflection profiles collected from the intraplate deformation area in the Central Indian Ocean Basin are used to describe brittle structures produced under compressive stress. Reflectors within oceanic basement are divided into four types: north-dipping and south-dipping reverse faults that are interpreted as reactivations of structures formed at the spreading-centre as outward and inward dipping faults respectively; lower-angle, north-dipping reflectors that probably represent new faults or faults just initiating; and sub-horizontal reflectors within the uppermost crtuhsat t are interpreted as hydrothermal alteration fronts. Within the sedimentary cover upwards fault propagation shows the faults steepening from c. 40" just above basement to near vertical and is preceded by sediment folding. A fractal analysis of faulting suggests two fault populations possibly reflecting different criteria for brittle failure. Measurements of north-south crustal shortening indicate a shortening rate of (2+.5 0 .9) mm a-', which is at the lower end of predictions from plate motions, but significant enough to recognize this area as a diffuse plate boundary. The formation of long-wavelength basement undulations and the reactivation on fracture zones and ridge-parallel fault fabrics are linked in a unified tectonic model driven by the high level of intraplate compressive stress in the area. There is little evidence from the seismic profiles for intraplate deformation starting before the widespread unconformity dated as 7 Ma.
0016-7649
955-966
Bull, J.M.
974037fd-544b-458f-98cc-ce8eca89e3c8
Scrutton, R.A.
390958b5-26fb-4588-bb56-b77b080fd568
Bull, J.M.
974037fd-544b-458f-98cc-ce8eca89e3c8
Scrutton, R.A.
390958b5-26fb-4588-bb56-b77b080fd568

Bull, J.M. and Scrutton, R.A. (1992) Seismic reflection images of intraplate deformation, central Indian Ocean, and their tectonic significance. Journal of the Geological Society, 149 (6), 955-966. (doi:10.1144/gsjgs.149.6.0955).

Record type: Article

Abstract

Multichannel seismic reflection profiles collected from the intraplate deformation area in the Central Indian Ocean Basin are used to describe brittle structures produced under compressive stress. Reflectors within oceanic basement are divided into four types: north-dipping and south-dipping reverse faults that are interpreted as reactivations of structures formed at the spreading-centre as outward and inward dipping faults respectively; lower-angle, north-dipping reflectors that probably represent new faults or faults just initiating; and sub-horizontal reflectors within the uppermost crtuhsat t are interpreted as hydrothermal alteration fronts. Within the sedimentary cover upwards fault propagation shows the faults steepening from c. 40" just above basement to near vertical and is preceded by sediment folding. A fractal analysis of faulting suggests two fault populations possibly reflecting different criteria for brittle failure. Measurements of north-south crustal shortening indicate a shortening rate of (2+.5 0 .9) mm a-', which is at the lower end of predictions from plate motions, but significant enough to recognize this area as a diffuse plate boundary. The formation of long-wavelength basement undulations and the reactivation on fracture zones and ridge-parallel fault fabrics are linked in a unified tectonic model driven by the high level of intraplate compressive stress in the area. There is little evidence from the seismic profiles for intraplate deformation starting before the widespread unconformity dated as 7 Ma.

Text
Bull_and_Scrutton_1992_preprint - Author's Original
Download (5MB)

More information

Published date: 1 December 1992
Organisations: Geology & Geophysics

Identifiers

Local EPrints ID: 346544
URI: http://eprints.soton.ac.uk/id/eprint/346544
ISSN: 0016-7649
PURE UUID: 47c74d4f-6663-4eed-a55c-cf0f73180ab3
ORCID for J.M. Bull: ORCID iD orcid.org/0000-0003-3373-5807

Catalogue record

Date deposited: 02 Jan 2013 10:36
Last modified: 15 Mar 2024 02:44

Export record

Altmetrics

Contributors

Author: J.M. Bull ORCID iD
Author: R.A. Scrutton

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×