Dating Oligocene-Recent siliciclastic sediment sequences from the Norwegian Sea
Bibliographic record
Abstract
The Norwegian Sea is crucial for ocean circulation and global climate and has therefore long been a focus in paleoceanography. However, precise dating of sediments has often proved difficult, due to poor preservation and endemism among microfossils and the discontinuous nature of many records. One important Norwegian Sea Site, Ocean Drilling Program (ODP) Site 643, is of particular interest, because of its location and long stratigraphic reach. Previously published magneto- and biostratigraphic age models diverge by ~1 Myr in the lower and middle Miocene, insufficient for global correlations. Here we present new palynological, notably dinoflagellate cyst (dinocyst) data from the lower and middle Miocene of ODP Site 643 and integrate these with existing palynostratigraphies of ODP Site 643. Additionally, we perform 40Ar/39Ar dating on selected tephra layers. We use these, combined with other microfossil bioevents, to reinterpret the existing magnetostratigraphy and construct a revised Oligocene to Recent biomagnetostratigraphic age model for this Site. We confirm the occurrence of three early and middle Miocene hiatuses and one early Pleistocene hiatus and refine their duration. Our age model further indicates a substantially older age for lower and middle Miocene sediments than previous dating has suggested. Finally, we combine our new age model with the integrated palynostratigraphy to provide updated ages of dinocyst bioevents and zone boundaries, which are at least applicable to the Norwegian Sea.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".