Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Pre-emplacement structural history recorded by mantle peridotites: an example from the Lizard Complex, SW England

Cook, C. A., Holdsworth, R. E., Styles, M. T. and Pearce, Julian A. 2000. Pre-emplacement structural history recorded by mantle peridotites: an example from the Lizard Complex, SW England. Journal of the Geological Society 157 (5) , pp. 1049-1064. 10.1144/jgs.157.5.1049

Full text not available from this repository.

Abstract

The Lizard Complex of SW England includes thrusted units of peridotites that were initially exhumed from upper mantle (c. 52 km) to lower crustal (c. 24 km) depths during a period of Early Devonian rifting and break-up. This basin closed during the Late Devonian, when the Lizard Complex was thrust towards the NNW along a major low-angle detachment and became incorporated within a series of Variscan thrust nappes. In the peridotites, a primary high-T and high-P spinel lherzolite mineral assemblage (c. 1119°C and c. 15.7 kbar) was progressively exhumed and re-equilibrated to conditions of lower T and P (c. 991–1010°C and c. 7.5 kbar) during the development of kilometre-scale mylonitic plagioclase- and amphibole-bearing mantle shear zones. These fabrics demonstrably pre-date emplacement related structures. The new structural and geochemical evidence from the peridotites also strongly suggests that the Lizard Complex formed in a rifted, non-volcanic continental margin setting, possibly in a pull-apart basin, rather than at a mid-ocean ridge. The P–T and textural evolution of the Lizard peridotites supports growing evidence that shear zones in the lithospheric upper mantle may to some extent accommodate large-scale displacements associated with crustal extension and continental breakup.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Ocean Sciences
Subjects: Q Science > QE Geology
Uncontrolled Keywords: Lizard Complex ; Variscan Orogeny ; Upper mantle ; Exhumation
ISSN: 0016-7649
Last Modified: 04 Jun 2017 02:04
URI: http://orca-mwe.cf.ac.uk/id/eprint/8500

Citation Data

Cited 30 times in Google Scholar. View in Google Scholar

Cited 26 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item