Structure, metamorphism and tectonic setting of metasedimentary rocks and mafic-ultramafic inclusions in the Dashwoods subzone of the Dunnage zone, southwestern Newfoundland

This study focuses on an area east of the Long Range Fault, on the western side of the Dashwoods subzone and contains all the major lithostratigraphic units characteristic of the Dashwoods subzone.;An upper age of deposition of the metasediments is approximately middle Ordovician as constrained by the age of the granitoid rocks. Silurian mafic bodies in the Dashwoods subzone have not been affected by high grade metamorphism or high degree of deformation and the Dashwoods subzone had probably stabilized by late Ordovician to Silurian time. (Abstract shortened by UMI.).;Metasedimentary rocks are separated into two main units: metapsammites to the west and metapelites to the east. Mafic-ultramafic inclusions lie within shear zones in the metapelites and are interpreted to represent parts of a disrupted ophiolite suite. The mafic-ultramafic rocks are interpreted to have undergone the full range of metamorphism and deformation that has affected the metasedimentary rocks. Geothermobarometry calculations suggest that the higher grade metamorphic event may have reached temperatures in the order of 800...