Taltson basement gneissic rocks: UPb and Nd isotopic constraints on the basement to the Paleoproterozoic Taltson magmatic zone, northeastern Alberta
Bibliographic record
Abstract
The Taltson magmatic zone is a 300 km long, northerly trending belt of Archean to Paleoproterozoic granitic basement gneiss, amphibolite, supracrustal gneissic rocks, and voluminous Paleoproterozoic magmatic rocks underlying northeastern Alberta and the southwestern portion of the Northwest Territories. Taltson basement gneissic rocks exposed in the southern Taltson magmatic zone in northeastern Alberta are composed of a lithologically diverse suite of banded gneissic rocks, including amphibolitic gneiss, paragneiss, and metaplutonic gneiss. Metaplutonic gneissic rocks are predominant; six new UPb ages range from 2.4 to 2.1 Ga. Taltson basement also contains tectonic slices and layers of Archean gneissic rocks dated at 3.2 Ga, 3.1 Ga, and 2.6 Ga. εNd(2.2 Ga) values of 1.6 to 14.3 and TDM ages of 2.593.73 Ga from Taltson basement rocks (27 new analyses) overlap with values for the western Churchill Province and are interpreted to represent Paleoproterozoic recycling of the latter. The similarity in UPb ages and partial overlap in Nd isotopic compositions of the Taltson basement gneissic rocks and the Buffalo Head terrane are consistent with the two domains representing a single Paleoproterozoic crustal entity, which evolved from variable contributions of depleted mantle and preexisting Churchill Province crust. Greater contributions from a depleted mantle component in the Buffalo Head terrane are suggested by the Nd data. Taltson basement gneissic rocks and Buffalo Head terrane may represent earliest Paleoproterozoic magmatism associated with breakup of the western Churchill Province prior to ThelonTaltson orogenesis.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| 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".