Diagenetic history of Triassic sandstone from the Beacon Supergroup in central Victoria Land, Antarctica
Bibliographic record
Abstract
Abstract The diagenetic history of Triassic sandstone from the Beacon Supergroup, Victoria Land, Antarctica, can be divided into three main phases of shallow burial diagenesis, contact diagenesis (temperatures of 200–300°C), and post‐contact diagenesis, on the basis of petrographic and geochemical analyses. Shallow burial diagenesis is characterised by minor compaction, K‐feldspar alteration to illite, and quartz cementation. Contact diagenesis is related to emplacement of dolerite intrusions and basalt flows during Gondwana break‐up at 180 Ma. This high‐temperature diagenetic phase is dominated by zeolite cementation, even in sandstone poor in zeolite precursor materials. Elevated thermal conditions associated with the igneous intrusions are suggested by increased illite crystallinity, but strong evidence for contact metamorphism is missing. Post‐contact diagenesis is signified by zeolite and K‐feldspar dissolution, and local quartz, calcite cementation, and minor albite and K‐feldspar precipitation. This diagenetic phase is possibly related to renewed (hydro‐) thermal activity in Victoria Land in association with rifting of New Zealand and Australia from Antarctica at c. 96 Ma.
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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 | 0.004 | 0.003 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".