Crustal Noble Gas Isotopic Characteristics in Low-Permeability Ordovician Sedimentary Rock, Eastern Flank of the Michigan Basin
Bibliographic record
Abstract
This study presents noble gas characteristics of porewater in the Ordovician low-permeability drill cores, which were vacuum-sealed in Al-foil bags and collected over a decade ago on the eastern flank of the Michigan Basin. Noble gas ratios and concentrations reveal crustal noble gas features as well as radiogenic 4He, 40Ar, and 136Xe components. The measured noble gas ratios in this study agree with measurements previously made in the Ordovician brine samples from the western flank of the Michigan Basin. However, unlike water samples from the western Michigan Basin, no mantle-featured noble gas components are found in the Ordovician rock porewater from this site. The Ordovician porewater residence time is quantitatively estimated with both He and Xe radiogenic ingrowth, yielding an average of 251 million years (m.y.). This porewater residence time estimate is comparable with the previous He accumulation time estimate at the same study site that yielded 260 m.y. The radiogenic noble gas ingrowth demonstrates long-term confinement of porewater and concomitant gases within the Ordovician low-permeability rock investigated. The remarkable preservation of gases in these well-sealed vapor-barrier Al-foil bags provides an economical and efficient possibility for noble gas out-diffusion sampling from drill cores.
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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 | 0.000 | 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 | 0.000 |
| 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 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".