EARLY–MIDDLE ORDOVICIAN SEASCAPE-SCALE AGGREGATION PATTERN OF SPONGE-RICH REEFS ACROSS THE LAURENTIA PALEOCONTINENT
Bibliographic record
Abstract
ABSTRACT During the late Cambrian–Early Ordovician interval the predominant non-microbial reef builders were sponges or sponge-like metazoans. The lithological and faunal composition of Cambro-Ordovician sponge-dominated reefs have previously been analyzed and reviewed. Here we take the relationship between reef aggregation pattern at reef to seascape scale into account, and look for changes during the Early–Middle Ordovician interval, in which metazoans became dominant reef builders. In a comparison of sponge-rich reefs from eight sites of the Laurentia paleocontinent three different seascape level reef growth patterns can be distinguished: (1) mosaic mode of reef growth, where reefs form a complex spatial mosaic dependent on hard substrate; (2) episodic mode, where patch reefs grew exclusively in distinct unconformity bounded horizons within non-reefal lithological units that have a much larger thickness; and (3) belt-and-bank mode, where reefs and reef complexes grew vertically and laterally as dispersed patches largely independent from truncation surfaces. The distinct modes of growth likely represent specific reef forming paleocommunities, because they differ in content and abundance of skeletal metazoan framebuilders, bioturbation intensity of non-skeletal reef sediment matrix, and in association of reef growth with underlying hard substrate. We suggest, based on a review of Laurentian reef occurrences, that the mosaic mode dominated in Early Ordovician strata and that the dominance shifted toward the belt and bank mode from Middle Ordovician strata onward.
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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".