SEDIMENTOLOGY, TAPHONOMY, AND PALEOECOLOGY OF METER-SCALE CYCLES FROM THE UPPER ORDOVICIAN OF ONTARIO
Bibliographic record
Abstract
Abstract The Upper Ordovician (Caradoc) Collingwood Member of the Lindsay Formation, southern Ontario, Canada, is a strikingly cyclic package of clastics and carbonates. Cycles are 50–150 cm thick and comprise four major components: (1) dark gray to black, organic-rich, laminated shales that grade upsection into (2) dark to light gray calcareous shales or mudstones, (3) lenticular to tabular concretionary argillaceous limestones, and typically (4) light gray calcareous, fossiliferous mudstones or shales and marls. Black shale units have a characteristically sharp basal contact and overlie a condensed shelly pavement. Fossil in shales are preserved as pavements or stringers of trilobite, ostracode, and brachiopod debris, with strong taphonomic bias as a result of prolonged exposure at the sediment-water interface. Gray mudstones and marls are bioturbated and contain numerous low-diversity orthid brachiopod pavements. Persistent tabular concretionary limestone bands were formed by early diagenetic cementation. These concretionary units include shelly beds that alternate with less fossiliferous calcareous mudstones containing noncompressed, spar-filled burrows and articulated, sometimes in situ fossils. Variation in fossil abundance is the result of cyclic variation in sedimentation, ranging from periods of condensation to rapid burial. Collingwood cycles involve upsection changes including: (1) benthic oxygenation from lower dysoxic to fully oxic biofacies, (2) increased frequency and episodicity of sedimentation, (3) higher net sedimentation rate within gray mudstone to carbonate intervals, (4) increased environmental energy level, and (5) diagenetic cementation of muds a few centimeters below cycle tops. Consistency of these variations suggests an allocyclic mechanism for the Collingwood cycles related to short-term fluctuations in eustatic sea level or climate.
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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 | 0.000 | 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".