Iodine proxy evidence for increased ocean oxygenation during the Bitter Springs Anomaly
Bibliographic record
Abstract
The Neoproterozoic Bitter Springs Anomaly (BSA; 810-800 Ma) is characterised by an 8 ‰ negative δ 13 C excursion and is coeval with multiple indicators of increasing oxygenation of the ocean and atmosphere.Here, we use carbonate iodine contents to provide the first constraints on the evolution of local upper ocean redox conditions spanning the BSA.Iodine speciation in seawater is strongly redox sensitive, and carbonates precipitated proximal to O 2 -depleted water record low I/(Ca + Mg).Data from the Akademikerbreen Group of Svalbard show a major rise of I/(Ca + Mg) during the recovery phase of the BSA.Other relatively high I/(Ca + Mg) values are also associated with rising δ 13 C throughout the section.Combined with existing palaeoredox proxies (e.g., Cr and S isotopes), our new iodine data most likely reflect an oxygenation event.
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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 | 0.000 | 0.000 |
| 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".