Data report: bulk mineralogical composition of Cascadia margin sediments, IODP Expedition 311
Bibliographic record
Abstract
The bulk mineralogical compositions of sediment samples from Sites U1325-U1329, northern Cascadia margin, were determined by X-ray diffraction analyses.The results document a highly variable mineralogy dominated by detrital components, mainly quartz, feldspar, mica, and clay minerals.Carbonate minerals are present only in minor amounts (<5 wt%).The long-term variations in the relative abundance of each mineral correspond to the particular lithostratigraphic units.zone accretionary prisms ("Expedition 311 summary" chapter, this volume).For this purpose a transect of four sites (from southwest to northeast, Sites U1326, U1325, U1327, and U1329) was cored through the northern Cascadia margin off Vancouver Island, representing different stages in the evolution of gas hydrate formation in an accretionary prism from its most recent stage at the deformation front in the southwest (Site U1326) to its final stage in shallower waters in the northeast (Site U1329).Additionally, a cold vent (Site U1328) with active fluid flow was investigated.Corresponding to the tectonic setting, a vertical and lateral highly variable lithology was cored, with frequent intercalation of turbiditic sediments and extensive active faulting near the deformation front (Davis and Hyndman, 1989).Both turbidites and faulting are important for the gas hydrate distribution in the sediment column, whereas faults or fractures act as a fluid conduit; as proposed especially for Site U1328 ("Expedition 311 summary" chapter, this volume; Riedel et al., 2006), coarse-grained turbidites may provide the pore space needed for gas hydrate accumulation.Qualitative assessment of the bulk mineralogy could therefore give additional information about gas hydrate formation processes and might be useful for the study of authigenic carbonates that formed associated with gas hydrates (e.g., Bohrmann et al., 1998).
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".