Carbonate Sedimentology and Diagenesis of an Upper Ordovician Sponge-microbe-cement Mound on Southampton Island, Nunavut, Canada
Bibliographic record
Abstract
The Hudson Bay Basin is the largest intracratonic basin in North America, but remains a frontier area for our knowledge of its stratigraphy and sedimentology and its hydrocarbon potential. Large domal reefs (up to 10 m thick and 500 m wide) in the Upper Ordovician Red Head Rapids Formation on Southampton Island developed on the margin of this shallow-marine evaporitic basin in which physical and chemical seawater parameters were distinct from the open ocean and in which a diverse community of reef-building and dwelling metazoans was unable to flourish. The main reef facies comprise boundstone and cementstone composed of various proportions of early-calcified sponge tissues, microbial encrusters, synsedimentary cement and small colonial metazoans. The accretionary mechanisms of the Red Head Rapids reefs were mainly the result of framebuilding by early-calcified sponges and small colonial corals and binding by calcimicrobial elements for the boundstone facies, and of massive aragonitic cement precipitation near the seafloor for the cementstone facies. These Upper Ordovician reefs, in which microbialites dominate but coexist with metazoans, were more widespread in the Early Ordovician immediately prior to the Middle to Late Ordovician expansion of skeletal-dominant reefs. The Upper Ordovician reefs on Southampton Island, porous and locally bitumen impregnated, underwent early marine, near-surface and progressive burial diagenesis; reducing its primary porosity but significantly increasing its secondary porosity. They represent one of the major untested petroleum play types identified in the Hudson Bay Basin.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.003 | 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) | 0.002 | 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".