First application of high-resolution X-ray computed tomography to quantify the fossil record of foraminifera: The Nicola bed, Monte San Nicola, Sicily; type area for the Quaternary System
Bibliographic record
Abstract
The distinctive microlaminated Nicola bed marks the base of the Quaternary System at the type locality of Monte San Nicola in southern Sicily. We have analysed a sediment block that traverses the Nicola bed at the Mandorlo section located ∼400 m WNW of the GSSP. Primary sedimentological and ichnofabric analysis of the polished surface combined with X-ray computed tomography (CT) reveals changes in dissolved bottom water oxygen levels before, during and after deposition of the Nicola bed, beginning with a progressive but rapid transition to anoxia at its onset. A more gradual recovery to oxygenated conditions followed Nicola bed deposition. Planktonic foraminifera are recognised by X-ray CT as either empty or infilled near-spherical voids, and the individual volume (≈size) is estimated for each test in addition to its position in the sediment block. Pronounced foraminiferal abundance peaks through the Nicola bed, with a frequency of hundreds of years, suggest (quasi-)cyclical changes in the mixed layer of the water column, thereby implicating either high-frequency oscillations within the climate system or the long-term modulation of solar cycles. This is the first study to explore the distribution of foraminiferal tests through a sediment block using X-ray CT, revealing its potential as an inexpensive non-destructive method for the quantitative study of microfossils at extremely high stratigraphic resolution.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".