The Depositional Environments and Provenance Characteristics of Selected Sediments, South of Yewa River, Eastern Dahomey Basin, South Western Nigeria
Bibliographic record
Abstract
An inorganic geochemical study of a clay and shale sediments sequence around Araromi and Irogunakere (the Southern part of Yewa River), Eastern dahomey basin, south western Nigeria, was carried out to determine the sediment's depositional conditions, provenance and tectonics.Fifteen shale and clay sediment samples underwent mineralogical and geochemical analysis involving major, trace and rare earth element analysis at acme analytic laboratory, Ontario, Canada using an ICP mass spectrometer Elan 6000).Mineralogical studies using X-ray diffraction analysis revealed prominent kaolinite, montmorillonite and illite peaks; accessory minerals included quartz and microcline.Major element abundance showed that the shale samples consist of SiO 2 (44.77%),Al 2 O 3 (15.01%)and Fe 2 O 3 (5.75%),constituting more than 65% of bulk chemical composition.Thirty-four elements trace metals; heavy rare earth elements and light rare earth elements analysis were quantified from the geochemical analysis.The shale sediments exhibit higher Ni, Ba, CO, Zr, Rb and Th concentrations than clay sediments, whereas clay samples are Sr-, Zn,, Pb-and U-enriched .Light rare earth element (La, Ce, Nd,Sm,Pr) were enrich in shale and clay sediment samples while, heavy rare earth elements (Tb, Yb, Lu, Gd ,Dy ,Ho, TM and Eu) are depleted.High TiO 2 and Rb/K 2 O values also indicated that the shale and clay samples were matured.Geochemical parameters such as U, U/Th, Ni/Co and Cu/Zn ratios indicated that these shales were deposited in oxic conditions; the Al 2 O 3 /TiO 2 ratio suggested that intermediate igneous rocks were probable source rocks for the shale, while mafic rocks were suggested as being source rocks for the claystone.However, the La/Sc, Th/Sc, Th/Co ratios and shale and clay sediment plots revealed that they came within the range given for felsic rocks as provenance, thereby suggesting mixed provenance for the sediments.A passive-margin tectonic setting was adduced for the sedimentary sequences.
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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 | 0.001 | 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 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".