Dinoflagellate cyst evidence for the age and palaeoenvironments of the Upper Eocene–Oligocene Dabaa Formation, Qattara Depression, north Western Desert, Egypt
Bibliographic record
Abstract
The palynological investigation of 30 outcrop samples from seven sites in and near the Qattara Depression, north Western Desert, Egypt, has yielded six samples from three sites containing poorly to well-preserved assemblages including dinoflagellate cysts, freshwater algae, acritarchs, pollen and spores. The sites have not been dated previously, but dinoflagellate cyst evidence reveals an early or middle Rupelian (Early Oligocene) age for one sample (overlapping ranges of Tuberculodinium vancampoae and Phthanoperidinium comatum) and early Rupelian or older (occurrence of Lentinia serrata) for another, establishing time equivalence with the Upper Eocene–Oligocene Dabaa Formation. The palynological assemblages reflect fluctuating conditions on the southern margin of the Tethys/Paratethys Ocean, with the frequent co-occurrence of Homotryblium floripes, Pediastrum and Botryococcus reflecting restricted and probably lagoonal marine environments influenced by seasonal river inflow. Despite low global sea levels during the Early Oligocene, marine conditions evidently extended as far south as the southern Qattara Depression. Outcrops in the north Western Desert are typically deeply weathered and barren of palynomorphs, this being the first report of dinoflagellate cysts from surface sections of the Qattara Depression and its surroundings.
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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 | 0.001 |
| 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 | 0.000 |
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".