Upper Cretaceous to Neogene palynology of the Melut Basin, Southeast Sudan
Bibliographic record
Abstract
Abstract The palynology of the Upper Cretaceous to Neogene non-marine succession in the Melut Basin, southeast Sudan was investigated. The palynomorphs are overwhelmingly of terrestrial origin, but rare brackish water dinoflagellate cysts and scolecodonts were encountered from the Lower Miocene and Oligocene-Miocene. Mangrove pollen, which is common in coeval West African coastal basins, is rare and inconsistent. Examples are Spinizonocolpites (Nypa) from the Campanian-Maastrichtian to Eocene and Rhizophoraceae (Zonocostites ramonae) from the Neogene. Based on the stratigraphic distribution of selected pollen and spores from four exploration wells, eight informal palynozones from the Campanian to the Neogene are proposed. The zones, in stratigraphically ascending order, are as follows: Assemblage Zone I, Campanian (lower Melut Formation); Assemblage Zone II, Campanian-Maastrichtian (middle Melut Formation); Assemblage Zone III, Maastrichtian (upper Melut Formation); Assemblage Zone IV, Paleocene (Yale Formation); Assemblage Zone V, Eocene (upper Yale and Adar formations); Assemblage Zone VI, Oligocene-Early Miocene (Jimidi and lower Miadol formations); Assemblage Zone VII, Early Miocene (uppermost Miadol and lowermost Daga formations); and Assemblage Zone VIII, Late Miocene-Pliocene (Daga Formation). The ages are based on stratigraphic positions and a series of first downhole appearances of key species such as Foveotricolpites cf. giganteus (Zone I), Auriculiidites reticulatus (Zone II), Ariadnaesporites spinosus (Zone III), Periretisyncolpites giganteus (Zone IV), Retistephanocolpites williamsii (Zone V), Cricotriporites camerounensis (Zone VI), Perfotricolpites digitatus (Zone VII), and Peregrinipollis nigericus (Zone VIII). Palynofacies investigations indicated differences between the Late Cretaceous and Paleogene-Neogene paleoenvironments of the sections studied. The coexistence of structured organic palynodebris with pteridophyte spores, including those of water ferns (Ariadnaesporites), in the Upper Cretaceous strata suggests swampy conditions within a predominantly fluvial setting. The frequent occurrence of Palmae pollen indicates warm, humid conditions during the Late Cretaceous, although seasonal or hinterland aridity is suggested because of the occurrence of ephedroid pollen. Late Paleogene and Neogene assemblages are characterized by amorphous organic matter, fern spores, freshwater algae, and Gramineae pollen. Deposition in lacustrine habitats under warm, humid conditions is inferred. The occurrence of Gramineae pollen, mainly in the Neogene, indicates the development of grassy areas in a seasonally dry climate. A short marine incursion may have taken place during the Oligocene-Miocene, due to the rare occurrence of brackish water dinoflagellate cysts and scolecodonts.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".