Clay Aquitards as Archives of Holocene Paleoclimate: δ <sup>18</sup> O and Thermal Profiling
Bibliographic record
Abstract
Paleoclimatic conditions in the Holocene were reconstructed from a detailed vertical profile of pore water delta(18)O and a series of downhole thermal profiles at a thick, hydrogeologically simple, aquitard research site in the Northern Great Plains of Saskatchewan. Reconstructions were obtained using the theory of one-dimensional diffusive transport and an empirical Bayesian inversion technique. Inversion of the delta(18)O profile shows that input signal consists of a sudden increase of +6 per thousand (corresponding to a temperature increase of about 18 degrees C) at about 12,000 years before present (BP), after which no measurable change in delta(18)O is apparent to present day. This research shows, at this location, that there is no evidence of large amplitude temperature shifts in the Holocene and supports the commonly used assumption in ground water studies of constant atmospheric delta(18)O values throughout the Holocene. Inversion of the temperature profiles suggests the ground surface temperature increased primarily in the last half of the 20th century, with a peak temperature (about 3 degrees C) circa 1990. For both profiles, the ability to resolve historical variability decays rapidly with time. For the temperature profiles, the decay in resolution precluded the development of reliable estimates of climatic conditions prior to about 1950 and, in the case of the delta(18)O profile, it prevented the precise definition of climate changes (e.g., Hypsithermal and Little Ice Age) in the Holocene.
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 | 0.001 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".