Carbon isotope systematics of <scp>T</scp>urrialba volcano, <scp>C</scp>osta <scp>R</scp>ica, using a portable cavity ring‐down spectrometer
Bibliographic record
Abstract
Abstract Over the past two decades, activity at Turrialba volcano, Costa Rica, has shifted from hydrothermal to increasingly magmatic in character, with enhanced degassing and eruption potential. We have conducted a survey of the δ 13 C signatures of gases at Turrialba using a portable field‐based CRDS with comparison to standard IRMS techniques. Our δ 13 C results of the volcanic plume, high‐temperature vents, and soil gases reveal isotopic heterogeneity in the CO 2 gas composition at Turrialba prior to its recent phase of eruptive activity. The isotopic value of the regional fault system, Falla Ariete (–3.4 ± 0.1‰), is in distinct contrast with the Central crater gases (–3.9 ± 0.1‰) and the 2012 high‐temperature vent (–4.4 ± 0.2‰), an indication that spatial variability in δ 13 C may be linked to hydrothermal transport of volcanic gases, heterogeneities in the source composition, or magmatic degassing. Isotopic values of CO 2 samples collected in the plume vary from δ 13 C of −5.2 to −10.0‰, indicative of mixing between atmospheric CO 2 (–9.2 ± 0.1‰), and a volcanic source. We compare the Keeling method to a traditional mixing model (hyperbolic mixing curve) to estimate the volcanic source composition at Turrialba from the plume measurements. The predicted source compositions from the Keeling and hyperbolic methods (–3.0 ± 0.5‰ and −3.9 ± 0.4‰, respectively) illustrate two potential interpretations of the volcanic source at Turrialba. As of the 29 October 2014, Turrialba has entered a new eruptive period, and continued monitoring of the summit gases for δ 13 C should be conducted to better understand the dominant processes controlling δ 13 C fractionation at Turrialba.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".