Gallium and Germanium Concentrations From the MER Alpha Particle X‐Ray Spectrometers: Evidence of Global Trace Element Enrichment
Bibliographic record
Abstract
Abstract The Mars Exploration Rovers (MER) Spirit and Opportunity , sent to Gusev crater and Meridiani Planum, respectively, determined the chemical composition of martian materials with their Alpha Particle X‐ray Spectrometers (APXS). The MER APXS was effective at routinely quantifying major, minor, and select (Ni, Zn, Br) trace elements at levels down to ∼50 ppm but often reached detection limits for other trace elements (e.g., Ga and Ge during typical individual analyses of a single sample). To enable precise quantification of additional trace elements, a database of MER APXS target properties (e.g., location, feature, target, formation, target type, sample preparation) was created, enabling the construction of a library of composite (i.e., summed) spectra with improved statistics. Composite spectra generated from individual spectra with shared characteristics have a higher potential for resolving and thus quantifying trace element peaks. Analyses of composite spectra from Meridiani Planum and Gusev crater indicate that the molar Ga to Al ratio is relatively constant throughout both regions and is in line with predicted values for the martian crust and measured values in martian meteorites. Gallium and aluminum likely do not volatilize and instead remain together during volcanism and aqueous alteration. In contrast, Ge is enriched at least an order of magnitude relative to martian meteorites, and the molar Ge to Si ratio is much more variable across Meridiani Planum and Gusev crater. Enrichment of Ge may be a global phenomenon resulting from volcanic outgassing of volatiles and subsequent overprinting by local mobilization and enrichment via hydrothermal fluids.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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 | 0.001 |
| 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".