Bibliographic record
Abstract
Abstract Bars are major sediment storage places within channels, and much is known about their character from proglacial and temperate regions. Little is know, however, about bar characteristics from ephemeral streams. This study describes the morphology and composition of simple and compound gravel bars in Nahal Zin, Israel, an ephemeral desert stream. A hierarchy of microscale, mesoscale and macroscale structures and bed forms was identified in Nahal Zin that is similar to the hierarchy described for perennial streams. While the hierarchy is similar between arid and perennial streams, bar composition patterns are distinct. Compound bars and unit bars in humid areas are known to have armored surfaces composed of structured gravels, whereas the bar surfaces of both unit bars and compound bars in Nahal Zin were found to lack surface structures and to contain a large amount of sand. In ephemeral streams, both accreted and dissected compound bars do not display any downstream fining; in contrast, downstream fining along bars in humid areas is well documented. The flashy nature of floods, high sediment supply, high sediment transport rates, and large amount of sand associated with the bars are likely reasons the surfaces were not armored. In Nahal Zin, erosion and accretion dominate the bar edges, and accretion alone dominates the platform part of the bars. In summary, sediments in ephemeral streams of the Nahal Zin type are well mixed, unsorted, and unlikely to leave a well-defined stratigraphic record. These characteristics are distinct from their counterparts in proglacial and temperate regions and may be useful when investigating paleoenvironmental conditions.
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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 | 0.002 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".