The incompleteness of turbidite records: Comparing direct monitoring of turbidity currents to deposits preserved in submarine fans (Pointe-des-Monts, eastern Canada)
Bibliographic record
Abstract
The recurrence of turbidity currents in submarine canyons is often assessed using sediment core records from submarine fans, which are generally assumed to reflect canyon processes. However, this assumption has rarely been tested. Here, we assess the completeness of modern sedimentary records in the Pointe-des-Monts submarine fan, located in the Lower St. Lawrence Estuary, eastern Canada, by comparing turbidity current activity derived from repeat multibeam bathymetry, direct monitoring observations, and short sediment cores. The timelapse bathymetry and monitoring results revealed that turbidity current activity over the last 15 years was primarily driven by storms, especially during ice-free winters. Since 2007, a minimum of nine turbidity currents were recorded by timelapse multibeam bathymetry and direct observations in the canyon system, many of which have led to the migration of cyclic steps within the canyon axis. However, turbidites recorded in the short sediment cores on the lobe predate all monitoring efforts, indicating a largely incomplete record of canyon processes preserved on the seafloor. The absence of modern turbidites (≤15 years) in the submarine fan is interpreted to result from bottom current reworking, bioturbation, and the dilution of turbidity currents as they become unconfined on the submarine fan. This study highlights that bottom currents can extensively remobilize turbidites, resulting in a largely incomplete record of turbidity currents on submarine fans. Consequently, caution is needed when reconstructing their recurrence and sediment dynamics using sediment cores, particularly in such dynamic nearshore systems.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".