Marine Aluminum Phosphate–Sulfate Authigenesis as a Phosphorus Sink During Mid‐Proterozoic Oxygenation
Bibliographic record
Abstract
Abstract Enhanced continental phosphorus input into the ocean has been suggested as a potential trigger for the transient oxygenation events during the mid‐Proterozoic; however, the response of phosphorus cycling to these marine oxygenations remains unclear. Here, we report the changes in phosphorus cycling associated with a ∼1.7 Ga transient oxygenation. Abundant authigenic aluminum phosphate–sulfate mineral svanbergite (SrAl3(PO4) (SO4) (OH)6; 8.02 ± 4.92 wt%) is identified within the ∼1.7 Ga Yunmengshan ironstones from the Xiong'er Basin, North China and other contemporaneous basins. This observation provides new evidence to support the suggestion that early diagenetic aluminum phosphate‐sulfate minerals could have represented a critical sink of marine phosphorus during the Proterozoic. We suggest that atmospheric oxygenation and concomitant changes in porewater redox chemistry may have enhanced the formation of early diagenetic phosphates, leading to a negative feedback on the oceanic phosphorus reservoir and atmospheric oxygen levels.
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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 | 0.000 |
| 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 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".