Investigating the relative timing of the introduction of allochthonous silt in postglacial eolian dunes of central Alberta, Canada using a portable OSL reader
Bibliographic record
Abstract
The porous nature of eolian dune sediments enables post-depositional silt and clay to be added to the dune profile with an open-ended timeline. The allochthonous silt results in depositional age-heterogeneity between sand and silt which could encumber investigations that employ portable optically stimulated luminescence (OSL) readers to construct luminescence profiles using unprocessed bulk samples. To establish an approach for ascertaining the relative timing of the introduction of silt, this study used a portable OSL reader to assess the level of allochthonous silt in the upper parts of ca. 15 ka old postglacial eolian dunes in central Alberta, Canada. Four dune profiles were sampled using an auger at 10 cm intervals to a depth of 300 cm. Each sample was sieved into sand and silt with clay fractions (>0.063 mm and <0.063 mm) and then measured with IRSL and post-IR blue OSL using a portable OSL reader. Signals of the bulk samples were also measured for comparison. Results showed that the difference in signal intensity between the bulk samples, sand, and silt with clay fractions was insignificant, suggesting no substantial allochthonous silt was introduced into the area during the Holocene. An alternative source for the silt could be in-situ frost weathering of quartz sand in dune sediment as confirmed by grain surface microtextures from scanning electron microscopy.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".