Paleontology and diamonds: geological environments associated with kimberlite emplacement, Lac de Gras, Northwest Territories, Canada
Bibliographic record
Abstract
Abundant fossil spores, pollen and marine algal cysts from individual shale xenoliths and finer clastic matrix in kimberlite samples allow the determination of depositional environments and ages of rock units in the inferred but now eroded cratonic sedimentary cover.Through analysis of depositional environments it is quite clear that the interior seaway extended over the craton in the early Late Cretaceous and again, at least partially, in the late Campanian, but by the Maastrichtian it had withdrawn, leaving a terrestrial landscape into which most Lac de Gras kimberlites erupted.The ages allow correlation of sequences in the Lac De Gras region with those of western Canada.Plant microfossils characteristic of latest Turonian through early Campanian, latest Campanian through early Maastrichtian, and late Paleocene ages have not been confirmed in the Lac de Gras xenoliths suggesting depositional hiatuses occurred within the now eroded sedimentary cover.During some of these times, erosion may have been removed strata leaving behind only enhanced thermal maturity profiles as a signature of their former presence.The synchroneity between the emplacement of the Greenland mantle plume and the concentration of kimberlite eruptions in the late Paleocene and earliest Eocene is discussed.
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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 | 0.001 | 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) | 0.006 | 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".