Environmental and temporal patterns in bioturbation in the Cambrian–Ordovician of Western Newfoundland
Bibliographic record
Abstract
The early Paleozoic emergence of bioturbating (sediment-dwelling and -mixing) animals has long been assumed to have led to substantial changes in marine biogeochemistry, seafloor ecology, and the preservation potential of both sedimentary and fossil archives. However, the timing of the rise of bioturbation and environmental patterns in its expansion have long been subjects of debate-resolution of which has been hampered, in part, by a paucity of high-resolution bioturbation data or of systematic investigations of facies trends in lower Paleozoic bioturbation. To address these issues, we conducted an integrated sedimentological and ichnological characterization of the Cambrian-Ordovician Port au Port succession and Cow Head Group of western Newfoundland, encompassing over 350 meters of stratigraphy logged at the centimeter to decimeter scale. We find that, across a wide range of marine facies, bioturbation does not on average exceed moderate intensities-corroborating observations from other lower Paleozoic successions indicating that the early Paleozoic development of bioturbation was a protracted process. Moreover, bioturbation intensities in the Port au Port succession and Cow Head Group are commonly characterized by considerable variability at even fine scales of stratigraphic resolution and changes in bioturbation intensity correlate strongly with variability in sedimentary facies. We observe that facies recording nearshore depositional environments and carbonate-rich lithologies are each characterized by the highest intensities of both burrowing and sediment mixing. These data highlight the need for a high-resolution and facies-specific approach to reconstructing the evolutionary history of bioturbation and suggest that average levels of bioturbation, although relatively low throughout this interval, increased notably earlier in nearshore marine settings.
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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 | 0.001 | 0.002 |
| 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".