Isotopic and geochemical characteristics of mid- to-late-Miocene continental and oceanic arc volcanic and intrusive rocks, central North Island and offshore, New Zealand
Bibliographic record
Abstract
Abstract Mid- to late-Miocene continental arc volcanism on the North Island of New Zealand is found in the Coromandel Peninsula, the Kiwitahi volcanic chain and the Taranaki Basin (Kora Volcano) offshore the western margin of the North Island. Coeval oceanic arc volcanism is also found along the offshore Colville Ridge/Kermadec Ridge north of New Zealand. This Pb–Sr–Nd–Hf isotopic study aims to evaluate mantle sources and potential crustal contaminants along these sections of the Miocene arc system. The Colville/Kermadec Ridge and Kora lavas have the lowest Sr (0.7029–0.7045) and highest Nd (0.51305–0.51292) ratios; the Coromandel and Kiwitahi lavas overlap (Sr = 0.704–0.706; Nd = 0.51268–0.51296). The Colville/Kermadec Ridge, Kora, and Coromandel/Kiwitahi rocks form three distinct arrays on Pb–Pb plots, all above the Northern Hemisphere Reference Line, but none trend towards local Mesozoic basement greywackes. Isotopic and trace element ratio variations suggest that subducted sediments are a component in Coromandel/Kiwitahi mafic lava sources. The younger, southern Kiwitahi lavas have a more depleted mantle source than that for the older, northern Kiwitahi chain. Evolved lavas commonly have interacted with Waipapa basement rocks. Kora rocks have compositions similar to those of back-arc lavas and have been emplaced as sills in a rift environment above a distinct subduction-modified mantle.
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 | 0.000 | 0.000 |
| 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".