LE3 .A278 2012

2012

Barr, Sandra
Dehler, Sonya A.

Acadia University

Master of Science

Masters

Geology

Earth & Environmental Sciences

Magnetic and gravity data from northeastern Cape Breton Island, southwestern Newfoundland, and the intervening Cabot Strait area were compiled, and a series of maps displaying magnetic (filtered total field, first and second derivative, and downward continuation) and gravity (Bouguer anomaly onshore, free-air anomaly offshore and horizontal gradient) information was generated using UNIX-based GMT software. With further constraints from previously published seismic reflection interpretations and detailed maps of onshore geology, six 2D subsurface models were generated with GM-SYS 4.2 2D modeling software. Based on geophysical signatures, anomalies in the offshore were matched to onshore faults, rock units, and pre-Carboniferous terranes. The Cabot Fault separates Grenvillian basement to the northwest from peri-Gondwanan Aspy/Port-aux-Basques/Exploits basement to the southeast. The Cape Ray Fault merges with the Cabot Fault so that Notre Dame subzone rocks do not extend into the Cabot Strait area. Linear magnetic anomalies extending from the Port-aux-Basques subzone in southwestern Newfoundland to the Aspy terrane of Cape Breton Island are inferred to be a result of orthogneissic plutons in Aspy/Port-aux-Basques/Exploits basement rock. Magnetic halos in the Cabot Strait appear to be caused by Silurian-Devonian plutons like those in the Burgeo Batholith. The Aspy-Bras d’Or terrane boundary is located north of the Ingonish magnetic anomaly which was resolved into five components representing Late Neoproterozoic dioritic and granodioritic plutons of the Bras d’Or terrane and the Ingonish Island Rhyolite. The Bras d’Or terrane can be traced to the Grey River area in southern Newfoundland. A model in the Bay St. George sub-basin showed Grenvillian basement characteristic of the Humber Zone, overlain by the salt-bearing Codroy Group and clastic Barachois Group.

The author retains copyright in this thesis. Any substantial copying or any other actions that exceed fair dealing or other exceptions in the Copyright Act require the permission of the author.

https://scholar.acadiau.ca/islandora/object/theses:259