Lithological and structural characteristics of the Lake Bosumtwi impact crater, Ghana: Interpretation of acoustic televiewer images
Bibliographic record
Abstract
Abstract— Bosumtwi is a very well‐preserved 1.07 Myr old, complex terrestrial impact crater located in south‐central Ghana, West Africa. The impact structure has a diameter of about 10.5 km and was formed in 2.1–2.2 Gyr Precambrian metasedimentary and metavolcanic rocks. Drilling and logging was carried out during the Lake Bosumtwi Drilling Project (BCDP) which was supported by the International Continental Scientific Drilling Program (ICDP). One of the aims of this project is to achieve detailed information on the subsurface structure and crater fill of one of the best preserved large young impact structures. We interpreted the wireline logs and televiewer images. The physical properties including shallow resistivity, p‐wave velocity, magnetic susceptibility, and borehole diameter of the breccia differ significantly from those of the meta‐graywackes and slate/phyllites. Fractures observed in the televiewer images are interpreted to determine their characteristic structural features. The fracture dip angles are steep (50–70°) and the two main dip directions are southeast and southwest. Most fractures observed in the borehole are open. The indicated main stress direction is north‐south.
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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 | 0.001 | 0.001 |
| 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) | 0.003 | 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".