The Open UniversitySkip to content
 

Fluid infiltration along the South Armorican Shear Zone

Boulvais, P.; Lemarchand, J.; Gaboriau , M.; Tartèse, R.; Boiron, M.-C.; Bonnet, S. and Jegouzo, P. (2009). Fluid infiltration along the South Armorican Shear Zone. In: 19th V.M. Goldschmidt conference, 21-26 June 2009, Davos, Switzerland.

URL: http://goldschmidt.info/2009/abstracts/B.pdf#page=...
Google Scholar: Look up in Google Scholar

Abstract

Giant quartz veins associated with the South Armorican Shear Zone (SASZ) record huge fluid circulation during the Hercynian period. A regional-scale mapping of veins allows identifying two groups of veins on the basis of their geometric relationship with the SASZ. Veins from the fist group are parallel to the SASZ and associated with zones of intense deformation, veins from the second group developed on the southern edge of the SASZ, in an oblique meridian direction. The former likely record infiltration of fluids along permeable pathways; the latter may represent crustal-scale tension gashes associated with East-West σ3 direction in the regional context (North-South shortening and dextral working of the SASZ along a N120 direction). Microthermometry on fluid inclusions indicate that fluids were mostly aqueous with very low-salinity. Together with very low δ18O values of hydrothermal quertz, down to -2‰, these features argue for a surface origin. Scarce but significant CO2 fluid inclusions indicate a metamorphic contribution for some fluids, the origin of which probably lying in the exhumed metamorphic HT basement in the southern part of the region. Veins represent SiO2 sinks and we propose through a geochemical characterisation of deformed granites that mylonitic zones developed after syntectonic granites may represent SiO2 sources.

Item Type: Conference Item
Copyright Holders: 2009 Cambridge Publications and The Mineralogical Society
Academic Unit/Department: Science > Physical Sciences
Item ID: 32259
Depositing User: Romain Tartèse
Date Deposited: 02 Feb 2012 16:00
Last Modified: 27 Jan 2014 10:29
URI: http://oro.open.ac.uk/id/eprint/32259
Share this page:

Actions (login may be required)

View Item
Report issue / request change

Policies | Disclaimer

© The Open University   + 44 (0)870 333 4340   general-enquiries@open.ac.uk