Origin and Architecture of Deep-water Levee Deposits: Insight from the Ancient Rock Record and Experiments
Bibliographic record
Abstract
Although levee deposits make up a significant part of modern and ancient deep-marine slope systems, details of their internal lithological composition and stratal architecture remain poorly documented. At the Castle Creek study area, strata of the Neoproterozoic Isaac Formation (Windermere Supergroup) crop out superbly in a kilometre-scale section through a sinuous deep-water channel-levee system (ICC3). Levee deposits near the outer bend of the channel consist of sandstone-rich (sandstone-to-mudstone ratio of 68:42), medium- to thick-bedded turbidites interstratified with thinly-bedded turbidites. Structureless sandstone (Ta), planar laminated sandstone (Tb), non-climbing ripple cross-stratified sandstone (Tc) and massive and laminated siltstone (Td) are common. Thick beds generally thicken and then thin and fine laterally over about 300 m. Thin-bedded strata, in contrast, thin and fine negligibly over similar distances. In the distal part of the outer-bend levee (up to 700 m laterally away from the channel) strata consist predominantly of thin-bedded Tcd turbidites with a much lower sandstone-to-mudstone ratio (35:65). On the opposite side of the channel, inner-bend levee deposits are mudstone-rich, locally as low as 15:85, and consist mostly of thin-bedded, Tcd turbidites, although thicker-bedded, Ta-d turbidites are more common in the lower part of the section. Lateral thinning and fining of beds is more rapid than their outer-bend counterpart. Levee deposits of ICC3 comprise three stacked decametre-scale upward-thinning and -fining successions. Each is interpreted to record a depositional history consisting of lateral channel migration, levee deposition, channel filling, and distal levee deposition. During the early stage of increasing levee relief it is proposed that the termini of individual beds progressively backstep towards the channel margin resulting in an overall lateral thinning of the stratal profile. This interpretation notably contrasts the common assumption that levee morphology is the result of the vertical stacking of beds that dip. In addition to field studies, laboratory experiments were conducted to determine the depositional threshold of non-climbing ripple cross-stratification, which is common in levee strata of ICC3. It was determined that non-climbing ripples form when bed aggradation rates are less than 0.015 cm/sec, and most probably in flows made up of poorly sorted sediment.
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 | 0.001 | 0.001 |
| 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 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".