Geochronological and kinematic constraints on crustal shortening and escape in a two-sided oblique-slip collisional and magmatic orogen, Paleoproterozoic Taltson magmatic zone, northeastern Alberta
Bibliographic record
Abstract
The southern Taltson magmatic zone (south of 60°N) is a composite continental magmatic arc and collisional orogen resulting from the convergence of the Buffalo Head terrane with the Archean Churchill craton. Taltson basement (ca. 3.23.0 Ga and 2.42.14 Ga) and Rutledge River supracrustal gneisses (2.132.09 Ga) were intruded by voluminous I- and S-type magmatic rocks between 1.99 and 1.92 Ga. Taltson magmatic zone was deformed by three ductile shear zones: Leland Lakes, Charles Lake, and Andrew Lake, exhibiting both strike- and dip-lineated mylonitic domains. Kinematic data for shear zones are reported at microscopic, mesoscopic, and macroscopic (remotely sensed data) scale. We present field and UPb isotopic data (zircon and monazite) for magmatic and metamorphic rocks that constrain the timing of granulite to upper amphibolite-grade shearing in the Leland Lakes and Charles Lake (formerly Allan) shear zones to ca. 19381934 Ma. Foreland (easterly) vergent thrusting on the Andrew Lake shear zone is ca. 1932 Ma. Taltson shear zones were overprinted by widespread amphibolite- to greenschist-grade shearing, which is constrained by published 40 Ar 39 Ar and KAr dates on hornblende and muscovite to between ca. 1900 and 1800 Ma. We propose a crustal architecture, resembling a crustal-scale asymmetric flower structure, in which the Charles Lakes shear zone formed the fundamental shear zone of a middle to lower crustal sinistral transpression system that accommodated southward escape of crust in the upper plate of an oblique continental subductioncollision zone, with shortening partitioned into synchronous outwardly vergent thrust systems to the east and west of the main shear zone.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.009 | 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 teacher head, 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".