Albertiana Working Group Report : The case for the Global Stratotype Section and Point (GSSP) for the base of the Norian stage
Bibliographic record
Abstract
The Norian Stage is the longest stage in the Phanerozoic, and consequently it is important to define its base precisely for chronostratigraphy with a global stratotype section and point (GSSP). Previous work over many decades has indicated two possible candidate sections at Black Bear Ridge (British Columbia, Canada) and Pizzo Mondello (Sicily, Italy). Based on prior datasets the working group evaluated the global correlation potential of the two proposed primary markers, the conodont Metapolygnathus parvus and ‘flat-clam’ Halobia austriaca. We also evaluated secondary markers for these boundary datums for correlation, and the veracity of the proposed sections for GSSP status. The factual data and arguments for the proposed sections and datums are presented here. Through a two-stage process of option elimination in a voting process conforming with ICS guidelines, the working group decided by 60% majority to propose that the first occurrence datum (FAD) of Halobia austriaca in the Pizzo Mondello section at the base of bed FNP135A should become the ‘golden spike’ for the Norian. A secondary biotic marker for this boundary is the FAD of Primatella gulloae, in sample NA43, ca. 0 m below FNP135A and the FAD of Dimorphites noricus (sample NA42.1) ca. 3.5 m above bed FNP135 (indicating first subzone of the Jandianus Zone). The best physical secondary marker is magnetozone PM5n with the proposed boundary ca.40% from the base of PM5n. The strengths of this choice are that it also mains historical priority for ammonoid zonations, which placed the base Norian near to this level in Europe, North America and probably NE Asia, and Halobia austriaca is widely distributed in all paleolatitudes and is well established taxon.
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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 | 0.021 | 0.041 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.006 | 0.003 |
| Scholarly communication | 0.008 | 0.005 |
| Open science | 0.004 | 0.006 |
| Research integrity | 0.009 | 0.006 |
| Insufficient payload (model declined to judge) | 0.019 | 0.009 |
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".