Paleofluid-flow in a foreland basin, Northern Appalachians: from syntectonic flexural extension to Taconian overthrusting

Kirkwood, D., Ayt-Ougougdal, M., Gayot, T., Beaudoin G. and Pironon J.

(Journal of Geochemical Exploration, 2000, v. 69-70: 269-273)

Abstract

 

Structural relationship of fracture sets combined with fluid-inclusion data and isotopic composition of vein infill help constrain the P-T history of the Québec foreland basin. Results suggest that a warm (60 C), low salinity fluid of meteoric origin migrated through fracture networks and normal faults in the Ville de Québec rocks during the extensional collapse of the outer shelf in the lowermost Caradocian. This fluid was progressively mixed with a warmer (150-160 C) high salinity, basinal fluid associated with hydrocarbon gases and fluids. P-T modelling of inclusions related to the second pulse suggests a 3 to 4 km maximum burial depth for rocks of the Québec Promontory Nappe that we equate with thrusting of the nappe over the autochthonous margin and/or overthrusting by the Chaudière Nappe.