Impact of pre-existing structures on the emplacement and post-intrusion deformation of the Late Jurassic rift-related Notre Dame Bay Magmatic Province, Newfoundland, Canada
Bibliographic record
Abstract
In this field-based study, we investigate the Notre Dame Bay Magmatic Province (NDBMP) located in the Dunnage Zone, north-central Newfoundland, Canada. The NDBMP is a collection of rift-related intrusions dated at ca. 148 Ma (Late Jurassic, Tithonian), including the gabbroic Budgell Harbour Stock (BHS) and an associated lamprophyre dyke swarm. The host rock, composed of Ordovician-aged sedimentary and volcanic back-arc sequences, is metamorphosed to greenschist and locally amphibolite facies. The host rocks were deformed during the Ordovician-Silurian closure of the Iapetus Ocean. The primary Iapetus suture divides peri-Laurentian and peri-Gondwanan terranes in the Newfoundland Appalachians, and forms a Z-shaped flexure across the study area.Our research focuses on three primary aspects: 1) investigating the relationship between pre-existing orogenic structures and rift-related magmatism, 2) assessing the impact of this magmatism on the host rock, and 3) analysing the post-intrusive deformation of lamprophyres. The dataset includes 178 structural measurements of lamprophyres, and host rock structures, petrographic analysis of thin sections of the BHS, lamprophyres, and host rocks, and 3D structural models created from drone-based photogrammetry for selected outcrops.Our findings indicate that structures dating from the Ordovician to Silurian, associated with the Iapetus suture and Notre Dame Bay oroclinal flexure, significantly impacted the location and pathways of magmatism. This influence occurred at local scales, where dykes were deflected along bedding, foliation, and fold hinges, and on a larger scale along the Iapetus Suture. Additionally, multiple instances of magmatism affecting the host rock, including fracturing occurring subparallel to dykes, hydrothermal alteration, and brecciation were observed. Our investigation also identified three instances where dykes underwent brittle and ductile deformation due to the reactivation of pre-rift south-east dipping thrust faults with an oblique dextral motion towards the northeast. This movement is consistent with the direction of extensional forces the region experienced during Mesozoic rifting.Preliminary findings suggest that the reactivation of these Ordovician-Silurian thrust faults reflect larger scale transtensional reactivation of the Iapetus suture zone during Mesozoic rifting and opening of the Atlantic Ocean. These results enhance our understanding of structural inheritance, which is essential for accurately modelling rifting processes and reconstructing the opening of the North Atlantic Ocean.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".