Multiphase Volatilization of Halogens at the Soil‐Atmosphere Interface on Mars
Bibliographic record
Abstract
Abstract The Martian critical zone, especially its soil‐atmosphere interface, may host an active halogen cycle affecting habitability, as inferred from halogen trends observed in situ at Gusev and Meridiani, along with oxychlorine species detected in situ. However, the sinks and sources of the Martian halogen cycle remain poorly constrained, especially for Br, including the broader geographic significance of halogen volatility in soils. Here, we statistically analyze Br, Cl, and S distribution and associated cations in the soils of Gale Crater and compare the results with soils of Gusev Crater and Meridiani Planum. We further place the overall in situ soil trends in the framework of terrestrial natural evaporative halides and Mars‐analog evaporative experiments. We observe three lines of evidence that support preferential volatilization of Br versus Cl and S in Martian soils: (a) Unlike Cl and S, Br abundance decreases from subsurface to surface. (b) Br and Cl abundances correlate strongly at the relatively dust‐free and freshly exposed surface of the active Bagnold dunes, but Br‐Cl correlations weaken and Br concentrations decrease in less mobile surface soil. (c) Laboratory experiments show preferential Br loss over Cl and S under ultraviolet (UV) irradiation, consistent with the observed Br loss relative to Cl in Martian soil samples. Overall, these findings generally suggest that soil serves as a source for volatilized halogens. Specifically, soil‐atmosphere multiphase reaction pathways constitute a crucial component missing from purely gas‐phase photochemical models of the halogen cycle.
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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) | 0.000 | 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 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".