NEW CONSTRAINTS ON THE GEOLOGY OF BAIE VERTE PENINSULA, NEWFOUNDLAND: PART 2- STRUCTURE AND DEFORMATIONAL HISTORY OF THE PACQUET HARBOUR GROUP AND POINTE ROUSSE COMPLEX

In the Newfoundland Appalachians, the Baie Verte Peninsula represents one of the classical areas to study the structural evolution of the ophiolite and arc complexes of the Notre-Dame subzone. We present new structural data focused on ophiolitic and cover rocks of the Pacquet Harbour Group (PHG) and Pointe Rousse Complex (PRC). This area has been affected by at least four phases of regional deformation. D1 fabrics are poorly preserved and strongly overprinted. The D1 phase is interpreted to be related to the obduction of ophiolites during the Ordovician Taconian Orogeny. D2 represents the main tectonometamorphic phase. In the PRC, D2 fabrics are mostly parallel and associated with south-directed reverse faults. These culminate with the Scrape fault, a ductile shear zone that thrusts serpentinised mantle on basalts of the PHG. The intensity of D2 fabrics and accompanying metamorphism, decreases southwards across the PHG, culminating in a series of open folds in low grade mafic volcanic rocks. D2 is interpreted to be related to transpression and crustal thickening during the Silurian Salinic Orogeny. In the northern PHG, D2 fabrics are progressively affected by shallowly-inclined to recumbent folds, culminating in a structural window into the underlying continental margin metasedimentary rocks of the Ming's Bight Group. These folds have been interpreted to be cogenetic with extensional shear zones and inversion of reverse faults in an overall dextral, locally transtensional regime during the Early to Middle Devonian. An alternative interpretation considers that D2 and D3 structures are composite and originated from a protracted Salinic deformational event that involved overthrusting of the Ming's Bight Group on Ordovician and Silurian volcanic rocks. This interpretation implies that extension is post D2-3 and unrelated to recumbent folding. Two other set of folds affect the regional S2 fabric. A map-scale E-W trending fold apparently bisects most of the eastern peninsula. Its timing relative to extension remains uncertain. Finally, a set of open NNE to NNW trending late cross folds are observed. Ongoing structural analysis including geochronology will be critical in testing and refining the structure and deformational history of the Baie Verte Peninsula.