1996/05/01 by Ioannis Koukouvelas, I. Koukouvelas, G. Pe-Piper +3 · 28 citations
Computer Science · Earth and Planetary Sciences · #Batholith #Devonian #Extensional definition #Extensional fault #Fault (geology) #Geochemistry #Geochemistry and Geologic Mapping #Geological and Geochemical Analysis #Geology #Magma #Magma chamber #Mylonite #Petrology #Pluton #Seismology #Shear zone #Tectonics #Thrust fault #Volcano #earthquake and tectonic studies
paper · doi:10.1017/s001675680000902x
published in Geological Magazine 133(3), 285-298 (Cambridge University Press)
openalex publication_date 1996/05/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
Abstract Latest Devonian A-type granite-gabbro plutons, in part ductilely deformed, are spatially associated with the strike-slip Cobequid fault zone. The youngest intrusions are close to the Cobequid fault zone, which was the main conduit for magma. Two phases of deformation accompanying magma emplacement are recognized. Early magmas intruded ductile rocks during left-lateral oblique thrust movements. A second stage of right-lateral oblique slip normal faulting accommodated uplift of the plutons when coarse granite was emplaced in the crestal regions. Cross-cutting late stage porphyries, granitic clasts in marginal basins cut by granitic dykes, and superposition of brittle on ductile structures all indicate rapid uplift of the plutons. The geometry of the Cobequid fault zone shows that pluton emplacement was not the result of extension in releasing bends during transcurrent shear. Rather, flower-structure high-angle faults acted as magma conduits and space was created by two processes: translation of wall rocks along thrust faults at depth, developing space away from the master fault zone and backward collapse of the uplifted magma chamber creating space towards the fault zone.