U‐Pb geochronology and geochemistry of molybdenum‐bearing granodiorite porphyry at Copperstain Creek, west Nelson, New Zealand
Bibliographic record
Abstract
Abstract A molybdenite‐mineralised granodiorite porphyry at Copperstain Creek has a U‐Pb zircon age of 133.5 ± 0.2 Ma. This is older than the Early Cretaceous (126–105 Ma) Separation Point Suite, with which other molybdenum‐bearing granodiorite porphyries in west Nelson have been correlated on the basis of similar compositions and K‐Ar ages. The Copperstain Creek granodiorite differs compositionally from the high Na and Sr/Y rocks of the Separation Point Suite in having medium Na and low Sr/Y. Oxygen isotope δ 18 O magma values of ≤10‰ for the Copperstain Creek granodiorite and granites from the Separation Point Suite indicate that both are I‐type granites. However, the Copperstain Creek granodiorite porphyry has a minimum δ 18 O magma value of 9.4‰, which indicates a magma with a crustal component, whereas the Separation Point Suite granites have values (5.4–7.9‰) which are very primitive (“mantle‐like”). These new U‐Pb age and oxygen isotope data indicate that the Copperstain Creek granodiorite is not related to the Separation Point Suite granitoids.
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 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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".