| Title | Tectonic setting and regional significance of the 'Port aux Basques Gneiss', SW Newfoundland |
| |
| Author | Schofield, D I; van Staal, C R ; Winchester, J A |
| Source | Journal of the Geological Society vol. 155, 1998 p. 323-334, https://doi.org/10.1144/gsjgs.155.2.0323 |
| Links | Online - En
ligne
|
| Year | 1998 |
| Alt Series | Geological Survey of Canada, Contribution Series 1997068 |
| Publisher | Geological Society of London |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Newfoundland and Labrador |
| NTS | 11O/10NE; 11O/10NW; 11O/11NE |
| Area | Port au Basques |
| Lat/Long WENS | -59.6667 -58.5000 47.7500 47.5833 |
| Subjects | tectonics; general geology; igneous and metamorphic petrology; geochemistry; gneisses; orthogneisses; metabasites; paragneisses; schists; Port Aux Basques Gneiss; Grand Bay Complex; Port Aux Basques
Complex; Harbour le Cou Group; Big Barachois Assemblage; Isle Aux Morts Fault Zone; Margaree Orthogneiss; Kelby Cove Orthogneiss; Ordovician; Silurian |
| Illustrations | graphs; tables; cross-sections |
| Released | 1998 03 01 |
| Abstract | The 'Port aux Basques Gneiss' of southwest Newfoundland comprises three paragneiss and schist assemblages: the Grand Bay and Port aux Basques complexes, and the Harbour le Cou Group. They are intruded
by large volumes of basic sheets and coeval Middle Ordovician granitoids: the Margaree and Kelby Cove orthogneiss, which also cut a tectonic slice of earlier ultrabasic to basic rocks within the Grand Bay Complex: the Big Barachois assemblage. The
Grand Bay and Port aux Basques complexes are juxtaposed by the Late Silurian Isle aux Morts Fault Zone against the Harbour le Cou Group to the east, which dominantly comprises sillimanite and garnet-bearing, pyritiferous metasediments with
amphibolitic intrusions and meta-pillow basalts in its lower stratigraphic units. Geochemical studies have shown that metabasites of the Grand Bay Complex, Port aux Basques Complex, Margaree and Kelby Cove orthogneiss comprise Fractionated and
crustally contaminated MORE-like and within plate tholeiites, suggestive of an ensialic Okinawa type back-are basin. These have comparable characteristics to metabasites in the Harbour ie Con Group and suggest that these units comprise remnants of an
extensive Mid-Ordovician marginal basin developed within a promontory on the peri-Gondwanan continental margin. In contrast, the Big Barachois assemblage in part comprises a distinct suite of pre-Mid-Ordovician Island Are Tholeiites. |
| GEOSCAN ID | 208728 |
|
|