The Notre Dame Bay Magmatic Province (NDBMP) comprises a suite of Late Jurassic (Tithonian), rift-related alkaline mafic intrusions in north-central Newfoundland, Canada. This field-based study focuses on the Leading Tickles area, where the gabbroic Budgell’s Harbour Stock (BHS) and radial lamprophyre dykes intrude strongly folded and faulted Ordovician back-arc volcanic and sedimentary host rocks. The primary objective was to understand how pre-existing structures influenced the emplacement and post-intrusion deformation of the NDBMP.
This thesis employs a comprehensive methodology, including field mapping, thin section analysis, stereographic projections, kinematic and dynamic analysis, GIS visualization, and 3D analog modelling to analyze the interactions between pre-existing structures and the NDBMP. The results reveal that lamprophyres preferentially exploited pre-existing Paleozoic Appalachian structures associated with the Iapetus Suture Zone. Furthermore, magmatic activity weakened and deformed the host rocks, leading to the reactivation of Silurian thrust faults that deformed the lamprophyres post-intrusion. Movement along Luke’s Arm Fault Zone (LAFZ) in Leading Tickles may indicate a broader reactivation of the Iapetus Suture in northern Newfoundland during the Mesozoic. The variation in lamprophyre mineralogies and the presence of numerous radial dyke clusters suggest multiple magma sources coinciding with regional antiforms. / Thesis / Master of Science (MSc) / The Notre Dame Bay Magmatic Province (NDBMP) in north-central Newfoundland features Late Jurassic alkaline mafic intrusions linked to rifting. This study examines the Leading Tickles area, where gabbroic intrusions and lamprophyre dykes intersect older Ordovician rocks. The research explores how existing geological structures influenced the placement and deformation of these magmatic bodies. Using fieldwork, microscopic analysis, and 3D modeling, the study shows that ancient Appalachian structures guided the intrusion paths, and post-intrusion fault reactivations further deformed the rocks. The findings suggest multiple magma sources and broader regional tectonic movements during the Mesozoic.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/30305 |
| Date | January 2024 |
| Creators | Keefe, Emma |
| Contributors | Peace, Alexander, Earth Sciences |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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