CONIFEROUS TREES ASSOCIATED WITH INTERDUNE DEPOSITS IN THE JURASSIC NAVAJO SANDSTONE FORMATION, UTAH, USA
Bibliographic record
Abstract
Abstract: The Lower Jurassic Navajo Sandstone Formation of south‐west USA represents one of the largest erg deposits ever to have developed on Earth. Here, we report the widespread occurrence of silicified conifer stumps and trunks within interdune deposits near Moab, south‐east Utah. Where present as (par)autochthonous assemblages, trees are associated with the deposits of spring‐fed carbonate lakes. A few stumps preserved in growth position are rooted in aeolian sandstone immediately below the lake deposits, and evidently established on interdune soils in response to a rising water table. Following at least several decades of growth, trees were killed as the water table continued to rise forming shallow lakes containing ostracodes. Where present as allochthonous assemblages, randomly orientated tree trunks are associated with massive sandstone beds interpreted as fluidized mass flow deposits. These may have formed when dune slip‐faces collapsed during occasional heavy downpours of rain, destroying stands of trees. The occurrence of large conifers over a wide area of the Navajo Sandstone Formation in south‐east Utah may record long‐lived pluvial episodes during which the dune field stabilized, or reflect the erg‐margin position of the localities.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".