Lithostratigraphy of the Prince Albert Formation (Ecca Group, Karoo Supergroup)
Bibliographic record
Abstract
Abstract The Prince Albert Formation is a mudstone-dominated unit, which is located in the central and southwestern part of the Main Karoo Basin and the southernmost part of the Kalahari Basin in South Africa. It is Early Permian (Artinskian to early Kungurian) in age and is stratigraphically located between the underlying Dwyka Group and the overlying Whitehill Formation. In the Main Karoo Basin, its regional extent is limited to the cut-off boundary of the Whitehill Formation along a line from Hertzogville in the Free State to Coffee Bay in the Eastern Cape. Northeast of this boundary, it correlates with the lower part of the undifferentiated Ecca Group known as “Ecca Shales” and in the northern part of the basin, north of a line from Bloemfontein (Free State) to Harding (KwaZulu-Natal), with the Vryheid and Pietermaritzburg formations. The Prince Albert Formation is generally between 50 and 200 m thick, including the type area around Prince Albert, where a thickness of about 145 m was measured. It is thicker (230 to 497 m) in the region between Brandvlei and Jansenville and thins northeastwards to between about 30 and 60 m in the area between Kimberley and East London. In the Kalahari Basin, the formation is only 25 to 50 m thick, due to post-Karoo erosion of its upper part. The Prince Albert Formation contains fossils of marine invertebrates, palaeoniscoid fish, sharks, sponge spicules, foraminiferans, radiolarians, acritarchs, fragments of wood and leaves, together with ichnofossils in the form of fish trails, arthropod trackways and invertebrate burrows. High Rb/K ratios in the mudstones also indicate a marine shelf environment with suspension settling of mud being the predominant depositional process. Sedimentation was initiated during a major transgressive event following final melting of Dwyka Group associated ice sheets in southern Gondwana in the Late Palaeozoic. Water depths in the basin were probably about 400 m, but shallowed northeastward. In the proximal part of the basin northeast of Kimberley, sandstones in coarsening-upward successions represent prograding deltaic deposits derived from an adjacent source area to the north.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.000 | 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 teacher head, 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".