Early Earth’s hydrosphere: insights from the hydrothermally altered submarine lavas of the Eoarchean Saglek-Hebron Complex, Canada
Bibliographic record
Abstract
Estimating Earth's earliest hydrosphere conditions, including its temperature and isotopic composition, requires a rock whose protolith is robust enough to broadly preserve the O isotope data for billions of years despite isochemical metamorphism [1,2]. Numerous studies use zircon isotopic compositions [3] although zircons provide indirect and distant evidence of interaction between Hadean and Eoarchean rocks and the ancient hydrosphere. We here offer a direct investigation of rare outcrops of Hadean-Eorchaean age in Saglek-Hebron Complex in Northern Labrador, Canada ~3.8 Ga. We investigated a multitude of coeval rocks (basaltic pillows, dikes, sediments) mapped and previously well characterized compositionally and isotopically. These rocks are interpreted to represent submarine basalts and peridotites, with possible metakomatiites, are currently metamorphozed to amphibolite to granulite facies, and covered by metasedimentary rocks. We performed modeling of the metamorphic cycle on O and H isotopes and discuss the spatial distribution of O isotopic values.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".