Preservation of Cyanobacterial UVR‐Shielding Pigment Scytonemin in Carbonate Ooids Formed in Pleistocene Salt Lakes in the Qaidam Basin, Tibetan Plateau
Bibliographic record
Abstract
Abstract The formation of ooids and their use as a proxy to trace biogeochemical cycles have long been controversial. Here, we examined three beds of evaporite‐cemented ooids in the Qaidam Basin, including a layer of dolomitic ooids formed at 293 ± 4 kyr and cemented by gypsum at 266 ± 3 kyr, a layer of aragonitic ooids formed at 163 ± 1 kyr and cemented by halite at 111 ± 0.8 kyr, and another layer of aragonitic ooids formed at 38 ± 0.5 kyr and cemented by gypsum at 23 ± 0.3 kyr. The Raman spectra of organic extracts from these ooids indicate ubiquitous preservation of scytonemin, a unique cyanobacterial ultraviolet radiation (UVR)‐shielding pigment. This discovery suggests that ooids are capable of preserving biomarker from their depositional environment. Consequently, ooid may be used as a proxy for tracing biogeochemical processes and potentially applied to the search for life on Mars.
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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 | 0.001 | 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".