Thermal and structural evolution of the Grenville Channel shear zone, Coast Plutonic Complex, British Columbia
Bibliographic record
Abstract
Understanding the genesis of transpressive structures is important to modern structural geology because of the ubiquitous occurrence of transpression along plate margins. A key question is how strain partitioning occurs in regions of transpression. We report on a sequence of supercrustal and plutonic rocks from the western Coast Plutonic Complex exposed along Grenville Channel. Grenville Channel is a major topographic lineament which coincides with a Cretaceous aged sinistral shear zone. This shear zone, called the Grenville Channel shear zone (GCSZ), separates panels of rocks intruded by the 109 Ma Capitan Cove pluton to the west from rocks intruded by the 90 Ma Ecstall pluton on the east. The GCSZ is subvertical and northwest striking and contains rocks with mylonitic fabrics. Lineations have moderate to shallow plunges in the shear zone. Folds adjacent to the GCSZ rotate in a counterclockwise sense into parallelism with the shear zone indicating a shear zone directed increasing strain gradient. Geothermobarmetric studies conducted on metamorphosed country and igneous samples indicate pressures variations for the eastern side of the shear from 8 kbars in the north to a low of 5.2 kbars in the middle before a return to near 8 kbars at the southern terminus of the channel. Rocks to the west of the shear zone record homogenous pressures between 6.4 and 7.3 kbars. We interpret the structural data as evidence for strain partitioning during transpression between areas adjacent to the shear zone which were dominated by horizontal shorting and the shear zone itself which was dominated by sinistral transcurrent displacement. This pattern of strain partitioning produced differential uplift and exhumation along the shear zone causing the observed pressure differences.
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 | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 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) | 0.003 | 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".