Environmental and Substrate Control on Paleozoic Bioerosion in Corals and Stromatoporoids, Anticosti Island, Eastern Canada
Bibliographic record
Abstract
Abstract Bioerosion was a common process affecting corals and stromatoporoids in reef and off-reef facies on the carbonate ramp that spanned the Ordovician–Silurian boundary on Anticosti Island. The probable worm boring Trypanites was the dominant macroboring, penetrating more than 40% of 2,500 massive tabulate corals and stromatoporoids examined, occasionally in dense concentrations. The frequency of macroboring was influenced by conditions at the facies level reflected by changes in grain size, water depth, storm reworking of sediments, and the nature of the skeletal mass bored. These factors regulated exposure time of the host-substrate surface to the watermass and thus influenced bioerosion. Bored specimens are most common in muddy off-reef facies, moderate in sandy off-reef facies, and less common in reefs. In off-reef facies, storm-enhanced deposition and reworking of sediments were most important in the burial of eligible host substrates. In reefs, the high competition for space by encrusting epizoans, combined with sedimentation, limited macroborers that preferred to excavate dead skeletal substrates. Skeletal density was the most important property of the host substrate in controlling boring frequency. Macroborers favored a dense host skeleton likely for its enhanced mechanical strength and adaptability for unlined borings, despite requiring greater energy for excavation. High-relief host skeletons were bored more frequently than tabular forms, since their greater capacity to shed sediment would have resulted in more prolonged exposure above the seafloor. The probable bivalve boring Petroxestes pera is rare. Temporal changes in boring frequency appear to reflect local shifts in facies and relative sea level. Mass-extinction events near the O/S boundary, which eliminated some host corals and stromatoporoids, had no apparent effect on boring frequency.
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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".