Chapter 128: Stratigraphic Architecture and Depositional Processes of a Proximal Crevasse Splay and Genetically Related, Sinuous Channel Fill, Isaac Formation, British Columbia, Canada
Bibliographic record
Abstract
Abstract Channel-fill and adjacent lithofacies are well exposed in the deep-marine Neoproterozoic Windermere Supergroup. At one location, levee deposits are overlain by a proximal crevasse splay, which is overlain by a channel-fill complex. Levee deposits, which consist of thin-bedded, Tcd- or Tcde-division turbidites interstratified with thicker, coarser grained, more complete (Tabcd-division) turbidites (overbank splay deposits), accumulated adjacent to an active channel. Levee strata are overlain abruptly by a 23-m (75-ft)-thick, proximal-crevasse-splay deposit. The splay was initiated by avulsion of an adjacent, previously active channel. Energetic turbulent suspensions, now diverted through the levee and into the interchannel area, expanded rapidly, lost capacity, and incrementally constructed the crevasse splay. Depending on the rate of turbulent-suspension collapse, two lithofacies were deposited: (1) medium-bedded, fine- to medium-grained sandstone Tcd turbidites deposited by low-concentration dispersions, or (2) medium-bedded, coarse-tailed-graded, structureless, medium-grained sandstone deposited rapidly in submerged hydraulic jumps (turbidites were deposited from reconstituted dispersions that formed along the periphery of the jump). The intercalation of turbidites and structureless sandstones probably indicates lateral migration of the hydraulic jump and consequent compensational stacking of the two lithofacies. Splay deposits are overlain erosively by a ~14 m (~46 ft) channel-fill complex comprising two channel fills; the channel fills are separated by a zone with abundant mudstone intraclasts. Intraclasts may represent the eroded remnants of a mud plug deposited during the final stages of channel 1 (C1) fill that subsequently became eroded during the inception of channel 2 (C2). Both channel fills consist of medium- to thick-bedded, normally graded, coarse- to very coarse-grained sandstone and granule conglomerate that show a poorly developed fining-upward but better developed thinning-upward trend. Both channel fills show well-developed lateral accretion surfaces, suggesting that the channels had a sinuous planform.
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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 | 0.003 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".