Silicic tephras in Pleistocene shallow‐marine sediments of Wanganui Basin, New Zealand
Bibliographic record
Abstract
Abstract Vitric‐rich volcaniclastic horizons are important for correlation of glacio‐eustatic sedimentary cycles, both within the well known shallow‐marine record of Wanganui Basin, and other New Zealand terrestrial and deep marine records. They also record distal major rhyolitic eruptions from the Taupo (TVZ) and Coromandel (CVZ) Volcanic Zones that are lacking in proximal source areas. Twenty‐eight volcaniclastic horizons are recognised in the Castlecliffian and late Nukumaruan strata of Wanganui Basin from glass shard major element geochemistry and stratigraphic position, and are dated using magnetostratigraphy, orbitally tuned cyclostratigraphy and isothermal plateau fission track (ITPFT) ages. The major named volcaniclastic horizons (with ITPFT and/or astronomical ages, respectively) are: Onepuhi (0.57 Ma), Kupe (0.63 ± 0.08 Ma; 0.65 Ma), Kaukatea (0.86 ± 0.08 Ma; 0.90 Ma), Potaka (1.00 ± 0.03 Ma; 0.99 Ma), Rewa (1.20 ± 0.14 Ma; 1.19 Ma), Mangapipi (1.51 ± 0.16 Ma, 1.54 Ma), Ridge (1.56 Ma), Pakihikura (1.58 ± 0.08 Ma; 1.58 Ma), Birdgrove (1.60 Ma), Mangahou (1.63 Ma), Maranoa (1.63 Ma), Ototoka (1.72 ± 0.32 Ma; 1.64 Ma), Table Flat (1.71 ± 0.12 Ma; 1.65 Ma), Vinegar Hill (1.75 ± 0.20 Ma; 1.75 Ma), and Waipuru (1.79 ± 0.15 Ma; 1.83 Ma). The ITPFT ages are consistent with the astronomically tuned Geomagnetic Polarity Timescale. Volcaniclastic horizons in Wanganui Basin have been emplaced through a variety of primary and secondary processes, including direct tephra‐fall as well as transitional water supported mass flow through to hyperconcentrated flow. No gas supported flow deposits have yet been recognised. Only some horizons from Wanganui Basin can be chemically and chronologically linked to known TVZ eruptions, while others remain uncorrelated owing to proximal source area erosion and/or burial as well as vapour phase alteration and devitrification within near‐source welded ignimbrites. Nevertheless, many volcaniclastic deposits in Wanganui Basin can be reliably correlated to distal sedimentary successions in Auckland Region, Hawke's Bay and in Ocean Drilling Program (ODP) cores 1123 and 1124, to the east of New Zealand. The orbitally tuned chronology for ODP cores, which is calibrated by numeric ages on tephras and magnetostratigraphy, enhances inter‐regional correlation, providing an important framework for future pal‐aeoenvironmental reconstructions.
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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 | 0.001 | 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 | 0.001 |
| 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 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".