The onset of continental weathering recorded in Archean banded iron formations
Bibliographic record
Abstract
Abstract Early landmass emergence impacted marine chemistry and biosphere evolution by supplying nutrients through continental weathering. However, uncertainties persist regarding the timing of emergence and onset of early continental weathering. We present a compilation of germanium (Ge) and silicon (Si) in banded iron formations (BIFs) to assess Archean weathering. By leveraging the inverse correlation between Ge/Si ratios and Si contents in BIFs, we interpolate the evolution of Archean seawater Ge/Si for the first time. Our analyses reveal a stepwise decrease in Ge/Si, from near-hydrothermal values to those resembling continental input, at ca. 3.5 Ga. Based on a Ge-Si mass balance model, we propose that this shift is attributable to increased riverine fluxes, coinciding with the rapid emergence of continental crust. Significantly, this implies that two crucial prerequisites for the establishment of a marine biosphere were fulfilled in the early Archean: (1) the presence of marginal marine environments suitable for benthic and planktonic communities; and (2) a supply of terrestrially sourced nutrients.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.001 | 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 teacher head, 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".