Sedimentological Characterization of the Pre-Santonian Siliciclastic Deposits of Lower Benue Trough, Southeastern Nigeria
Bibliographic record
Abstract
The study which involves forty-one (41) sandstone samples’ collected from the area delimited by longitudes 7°00'E and 8°30'E and latitudes 5°00'N and 6°30'N, entailed evaluating and characterizing these sediments. Detailed field studies to establish the lithostratigraphy was carried out and fresh samples were subjected to petrographic, granulometric and heavy mineral analyses. Field observations revealed that the sandstones of the Awi Formation are angular to subangular, feldspathic, and generally fines upward and Amaseri are calcareous, indurated and laterally extensive. Agbani Sandstone consists of thick vertical sequences of ferruginized and indurated sandstones. Granulometric study shows medium to coarse-grained (0.78-1.30?), poorly to moderately sorted (0.87-1.19?), coarse to strongly fine skewed (-0.17-0.57?) and very platykurtic to leptokurtic (0.66-1.31?). This indicates mostly high energy condition and this is characteristic of fluvial environments. Petrographic studies for Awi samples indicate that they are texturally immature to submature, subarkosic arenites from a continental block provenance, while Amaseri Sandstones are texturally submature sublitharenites from a recycled orogen provenance. Agbani Sandstones are texturally immature to mature subarkosic arenites, sublitharenites and quartz arenites. Heavy mineral studies revealed zircon, tourmaline, rutile and hornblende to be common to all formations, sillimanite, kyanite, garnet, and staurolite are mostly common to Awi and Amaseri Sandstones while Agbani Sandstone has a dominance apatite with spinel. This suite of minerals suggests an acid igneous rock to typical dynamothermal metamorphic rock sources. The ZTR indices (74.0-94.4%) indicate mineralogically mature sediments. The study established that the pre- Santonian siliciclastic sequences of the Lower Benue Trough are texturally immature to mature and compositionally submature to supermature products of a continental block and recycled orogenic provenance under humid climates and deposited in fluvial to tidally influenced fluvial environments with high to moderate energy conditions humid climates which are deposited under high to moderate energy conditions.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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 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".