Gas Hydrate Offshore Vancouver Island, Northern Cascadia Margin
Bibliographic record
Abstract
Abstract This chapter reviews the extensive geophysical studies and Ocean Drilling Program (ODP) results that provide constraints on the occurrence, distribution, and concentration of deep-sea gas hydrate beneath the northern Cascadia margin offshore Vancouver Island. Most of this information comes from a wide range of seismic surveys and includes the mapping of the bottom-simulating reflector (BSR), as well as estimating gas-hydrate and free-gas concentrations. Recent additional constraints on the distribution and concentration of gas hydrate come from sea-floor-towed, controlled-source electromagnetic surveying and sea-floor compliance studies. These surveys and studies have been primarily deployed around a cold vent field, where seismic data show several broad blank zones, interpreted as fault-related conduits for focused fluid-gas migration, and where gas hydrate has been recovered in piston cores at the sea floor. Results from the ODP Leg 146 and the recently completed Integrated Ocean Drilling Program (IODP) Expedition 311 further constrain concentration estimates for gas hydrate and free gas in the sediments along the margin and also give insight into the complex formation mechanisms and controlling factors for gas hydrate occurrence in an accretionary complex. This summary was first presented in September 2004 at the AAPG Hedberg Research Conference on gas hydrates. Subsequently, 1 yr later, the drilling of IODP Expedition 311 resulted in a significant amount of new information and insight into the occurrence and formation processes of gas hydrate at the northern Cascadia margin. This chapter provides only a short summary of the results from that IODP Expedition. Reviews of the results from that drill coring and the downhole measurements are in progress.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".