COUPLING ATMOSPHERE AND SEDIMENT MELTS ACROSS THE ARCHEAN-PROTEROZOIC TRANSITION
Bibliographic record
Abstract
The Archean-Proterozoic transition marks a time of fundamental geologic, biologic, and atmospheric changes to the Earth system, including oxygenation of the atmosphere (termed the Great Oxygenation Event; GOE), and the emergence of continents above sea-level.The impacts of the GOE on Earth's surface environment are imprinted on the geologic record, including the attenuation of mass-independent fractionation of sulfur isotopes (S-MIF).Temporally overlapping geologic and geochemical observations (e.g. a change in oxygen isotope ratio of sediment melts) imply the widespread subaerial emergence of continents was coeval with atmospheric oxygenation.Here we present triple sulfur isotope ratios in pyrite and oxygen isotope ratios in garnet and zircon in a global suite of Archean and Proterozoic sedimentderived granitoids.These crustal melts record an increase in average 18O/16O isotope ratio and a disappearance of S-MIF in the Paleoproterozoic.The coupled behaviour of sulfur and oxygen isotope signatures imply a potential causal link between the emergence of continents and atmospheric oxygenation at ~2.3 Ga.Sample ID Major concentrations (reported as oxide wt %) SiO 2 TiO 2 2 Fe 2 O 3 MgO CaO Na 2 O K 2 O P 2 O 5 MnO LOI Total ASIACNK Reference 19GH11B 73.78 0.08 14.74 0.55 0.15 1.25 3.39 5.63 0.01 0.01 0.22 99.81 1.1 1.1 this study 19GH9 73.23 0.11 15.67 1.06 0.28 2.91 5.02 1.14 0.03 0.02 0.63 100.091.1 1.1 this study 19GH3 73.16 0.05 16.96 0.33 0.14 0.91 4.36 2.34 0.08 0.01 1.31 99.64 1.5 1.5 this study 17FIN01 74.00 0.04 13.38 2.13 0.28 0.26 2.05 7.40 0.11 0.02 0.58 100.26 1.1 1.1 this study 17FIN02 61.87 0.85 17.24 7.95 2.94 1.18 2.45 3.84 0.06 0.03 1.41 99.81 1.7 1.7 this study 17FIN03B 60.20 0.82 17.37 8.76 2.41 2.15 3.73 3.53 0.07 0.08 0.69 99.81 1.3 1.3 this study 17FIN04A 71.01 0.23 14.58 3.56 0.95 1.62 3.02 4.40 0.08 0.07 0.49 100.01 1.2 1.2 this study 17FIN05B 56.62 0.89 18.71 8.63 3.91 1.42 2.63 5.86 0.08 0.04 1.24 100.02 1.4 1.4 this study 17FIN06A 64.84 0.66 15.99 6.92 2.21 1.62 2.92 3.45 0.07 0.05 1.16 99.89 1.4 1.4 this study 17FIN06B 70.66 0.06 15.00 3.88 0.72 1.47 3.14 4.28 0.10 0.04 0.71 100.06 1.2 1.2 this study 18IM19 72.13 0.31 14.05 3.51 1.41 1.27 2.49 3.68 0.06 0.05 0.73 99.69 1.4 1.4 this study 15K-2 62.29 0.57 17.36 5.97 1.76 3.23 5.15 2.19 0.33 0.06 0.90 99.81 1.1 1.0 this study 18IM11B 61.93 1.06 18.04 6.58 2.18 2.88 2.80 3.58 0.07 0.06 0.22 99.38 1.3 1.3 Liebman et al. 2020a 18IM12B 69.05 0.14 14.73 5.97 1.90 2.85 2.32 1.03 0.03 0.13 0.77 98.92 1.5 1.5 Liebman et al. 2020a 18IM13C 70.74 0.33 14.84 3.06 0.87 3.04 3.29 1.73 0.10 0.01 1.00 99.01 1.2 1.2 Liebman et al. 2020a 18IM15B 65.23 0.58 15.48 7.01 2.12 3.52 2.84 0.96 0.09 0.09 1.34 99.25 1.3 1.3 Liebman et al. 2020a 18IM19 72.13 0.31 14.05 3.51 1.41 1.27 2.49 3.68 0.06 0.05 0.73 99.69 1.4 1.4 Liebman et al. 2020a 18IM20 63.52 0.26 17.78 6.13 1.81 2.63 3.50 3.05 0.07 0.07 0
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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 | 0.000 | 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".