(Table T1) Major and trace element concentrations of fine-grained sediments of ODP Hole 210-1276A
Bibliographic record
Abstract
Inorganic chemical composition and downhole variation of major and trace elements yields useful insights into the sediment provenance and paleoceanography of deep-sea sediments of deepwater continental margins. Here, fine-grained sediments were chemically analyzed at ~10-m intervals from the Eocene to Albian section at Site 1276. These sediments represent a time when background hemipelagic sedimentation was continuously beneath, or near, the calcite compensation depth (CCD). Additional samples were analyzed from the upper Paleocene-middle Eocene time interval to determine whether a volcaniclastic component is present, as suggested by petrographic studies of the coarser size fraction. Sediments recovered near the bottom of the hole show the effects of contact metamorphism adjacent to a sill of alkaline basalt. The overlying thick (~700 m) Albian succession (lithologic Unit 5) is indicative of a dominantly terrigenous source. Redox-sensitive trace elements (e.g., Cu, Ni, V, and Cr) are concentrated in organic-rich layers (black shales) that can be partially correlated with oceanic anoxic Events 1a-1d and 2. Beginning around the Cenomanian/Turonian boundary, a profound change took place to more oxidizing, slowly depositing sediments throughout the North Atlantic, characterized by relative enrichment in Fe, Mn, and related trace metals (e.g., Cu, Ni, and Cr). Similar background conditions persisted until the Eocene when local conditions at Site 1276 became more reducing, as indicated by more subdued colors and lower MnO contents. Moderate upwelling along the Newfoundland continental margin during the Eocene is suggested by the presence of relatively high values of silica coupled with opaline silica. Phosphate and associated trace elements (e.g., Ce and Y) are locally enriched, suggesting relatively high primary productivity. However, productivity was lower than on the conjugate Iberia margin at Deep Sea Drilling Project Site 398. Fine-grained terrigenous sediments at Site 1276 probably were mainly derived from the Grand Banks (e.g., Avalon uplift) and finally accumulated in deep water below the CCD mainly as mud turbidites and hemipelagites.
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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 | 0.002 | 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) | 0.028 | 0.005 |
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".