The coexistence of melts of hydrous copper chloride, sulfide and silicate compositions in a magnesiohastingsite cumulate, TUBAF seamount, Papua New Guinea. Canadian Mineralogist 42
Bibliographic record
Abstract
Direct evidence for a Cu–Cl-salt-hydrate melt in equilibrium with a complex system of silicate melts was found in a xenolith of magnesiohastingsite-dominant cumulate from the TUBAF Seamount, near Lihir Island, in Papua New Guinea. The cumulate formed less than 1.5 Ma ago in a magma chamber in the oceanic crust. Petrographic observations give evidence for the coexist-ence of two different silicate melts, a Cu–Fe–S melt, the salt-hydrate melt and a vapor phase as an intercumulus assemblage. The salt-hydrate melt crystallized to clinoatacamite, whereas the only mineral crystallizing from the silicate melt was hydroxylapatite. The two observed silicate melts are of trachyandesitic-tephriphonolitic and foiditic composition, clearly different from the trachybasaltic host-magma. Exsolution of the Cu–Fe–S melt likely took place in the temperature range between 960 ° and 557°C. Its chemical composition ranges between chalcopyrite and intermediate solid-solution (Iss). On the basis of experimental data of other salt-hydrate – silicate melt systems, the unmixing of the Cu–Cl-salt-hydrate melt must have taken place below 800°C. This unmixing demonstrates how metal-enriched magmatic fluids can enter pre-existing hydrothermal systems.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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".