Developing a South Pacific tephra framework: Initial results from a Samoan Holocene sequence
Bibliographic record
Abstract
ABSTRACT Tephra preserved in sediments form useful isochronous marker layers, linking disparate geological, palaeoenvironmental and archaeological records. The application of tephrochronology is greatly enhanced through the detection of macroscopically invisible tephra (cryptotephra). Here, we identify two discrete cryptotephra in Samoan lake sediments, the first identification of cryptotephra in the region outside of New Zealand. Geochemical data suggest one ash layer is from a local Samoan source, providing the first data on an eruption of this age, adding to knowledge of the local volcanic record. The second has a distinctive rhyolitic glass composition, which matches either that of Raoul Island in the Kermadec Arc (1800 km south of Samoa), or two currently submarine volcanoes in the Tongan Arc, ‘Volcano F’ and Lateiki/Metis Shoal (550 and 700 km south of Samoa, respectively). In all possible source cases, this points to a regionally significant eruption of a Kermadec–Tongan volcano at ca. 10 000 a bp . The study marks the first step in the establishment of a South Pacific tephra framework that can be used to answer questions about the synchronicity of changes in hydroclimate, vegetation and early Polynesian migration patterns, as well as providing more information on the volcanic history of Pacific island volcanoes.
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 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 | 0.004 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".