Branched GDGTs in Modern Soils in NW Canada and Late Pleistocene Loess Deposits in Eastern Beringia
Bibliographic record
Abstract
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) have been applied as a biomarker for past terrestrial temperatures; however, despite their abundance in soils globally, avenues for applying this biomarker to high-latitude regions have been little explored. This thesis uses i) modern soils from northwestern Canada (Whitehorse to Tuktoyaktuk) to test the applicability of existing globally calibrated brGDGT proxies and uses ii) late Pleistocene loess from the Klondike Goldfield region to apply said proxies. Local calibrations of brGDGT proxies in the eastern Beringian region are found to be very similar to their corresponding global calibrations, removing the need for local calibrations altogether. Reconstructions of late Pleistocene temperatures using brGDGTs uncover a temperature depression of 10°C during MIS 2 (presumably including the Last Glacial Maximum) compared to modern—a depression found by other studies. This research supports the use of globally calibrated brGDGT proxies in high-latitude regions.
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 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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 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 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".