Middle–Late Cambrian Rankenella–Girvanella reefs of the Mila Formation, northern Iran
Bibliographic record
Abstract
Following the collapse of the Early Cambrian archaeocyathan–calcimicrobial reef consortium, the Middle–Late Cambrian – Furongian was an interval dominated by purely microbial dendrolite and stromatolite reefs. However, among these latter, a few exceptional occurrences of metazoan reefs are known. One such reef complex occurs in the late Middle – early Late Cambrian – Furongian portion of the Mila Formation of northern Iran. In the otherwise low-energy interval of this formation, the anthaspidellid demosponge Rankenella hamdii sp. nov. is associated with encrusting Girvanella , eocrinoid plates, rhynchonelliformean brachiopod valves and subordinate hyoliths and trilobites in tempestite shell beds; these beds underwent synsedimentary cementation on the seafloor to form hardgrounds. In the succeeding, higher energy interval, a complex of metre-scale bioherms and (or) taphoherms incorporates toppled or transported Rankenella hamdii in association with brachiopods, echinoderm plates, trilobites and some red argillaceous lime mud. Among these, undoubted reefs were constructed from a framework of digitate Rankenella hamdii with thick Girvanella encrustations. These encrustations locally developed as subvertical columnar ministromatolites, which could also merge laterally to form more extensive masses. Subsequent pervasive cementation generated isopachous rinds that preserved the reef framework intact. Coeval and younger Cambrian anthaspidellid–calcimicrobial reefs are known from California–Nevada and Texas, USA. These were heralds of the Early Ordovician resurgence of metazoan reefs.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".