Structural inheritance and magmatism during continental breakup in West Greenland and Eastern Canada
Bibliographic record
Abstract
Continental extension causes rifting and thinning of the lithosphere that may result in breakup and eventually the initiation of seafloor spreading and passive continental margin development. Ambiguity exists regarding the roles of magmatism and structural inheritance during rifting and continental breakup during this process. This study focuses on the importance of these controls on the Mesozoic-Cenozoic separation between West Greenland and Eastern Canada. It is important to improve our knowledge of the processes that influenced breakup as the current understanding of these processes is limited and also to reduce hydrocarbon exploration risk in this tectonic setting. During this study passive margin processes were investigated using a variety of methodologies at a range of scales from that of conjugate margin pairs (Chapters 4 and 5), through margin and basin scale studies (Chapter 6) to the smallest scale on individual igneous intrusions (Chapter 7). At the largest scale an assessment of the magmatic and structural asymmetry between the conjugate margins of the Labrador Sea based primarily on field data and subsequent analysis near Makkovik, Labrador, but also other large-scale geophysical datasets demonstrated that early rifting was dominated by simple shear rather than pure shear. In such a scenario Labrador was have been the lower plate margin to the upper plate southwest Greenland margin. Further analysis of field observations indicated that rifting of the Labrador Sea region may have been aided by a favourably orientated basement metamorphic fabric and that observable onshore brittle deformation structures may be related to Mesozoic rifting. Further north in the Davis Strait, seismic interpretation at the margin and basin scale allowed a series of seismic surfaces, isochrons and a new offshore fault map to be produced. The results of this analysis demonstrated that the geometry of rift basins was primarily controlled by pre-existing structures, an assertion supported by observations of reactivation onshore in West Greenland. Finally, at the smallest scale, results of numerical modelling offshore Newfoundland demonstrated that even on non- volcanic passive margins, intrusive magmatism can influence thermal evolution. In addition, the presence of widespread igneous rocks on passive margins may be indicative of regional-scale thermal perturbations that should be considered in source rock maturation studies. Overall, the conclusion of this project is that both magmatism and structural inheritance have profoundly influenced the continental breakup between West Greenland and Eastern Canada, and that interplay between these two complex groups of mechanisms may have also contributed to the geological evolution of this area.
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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 | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".