Petrogeochemical Assessment of the Erelu-Oyo Dolerite Dyke and Associated Older Granites, Southwestern Nigeria
Bibliographic record
Abstract
The petrochemical studies of the medium- to fine-grained discordant dolerite dyke of Erelu, located within latitude 07°52′N to 07°54′N and longitude 003°52′E to 003°57′E, were carried out to characterize the rock, infer the petrogenesis in relation to the host rocks in the area, and advance the present knowledge on the dolerite dykes of the basement complex of southwestern Nigeria. The study involved fieldwork and random sample collection, where four dolerite, four granite, and six banded gneiss samples were collected and labeled. Thin sections of representative samples of the rocks were prepared following standard procedures, while the remaining rock samples were pulverized for major oxides and trace element determination using the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) method at Activation Laboratory, Ontario, Canada. The modal analysis results show that the dolerite is composed of olivine (40%), pyroxene (30%), plagioclase (10%), biotite (5%), and quartz (15%). Geochemical results revealed the average major elemental composition (%) as SiO₂ (48.62), Al₂O₃ (15.27), Fe₂O₃ (11.48), MgO (8.00), CaO (8.28), Na₂O (3.11), K₂O (0.82), TiO₂ (1.51), P₂O₅ (0.24), MnO (0.16), Cr₂O₃ (0.03), and LOI (1.85). The average trace element concentrations (ppm) are Ba (285.75), Ce (10), Co (51), Cu (54.5), Nb (7.75), Ni (162.25), Sc (19.75), Sr (436.75), Y (15.25), Zn (98), and Zr (111.25). The occurrence of pyroxene and olivine classifies the rock as olivine-dolerite and pyroxene-dolerite, while geochemical evidence suggests a tholeiitic origin for the dolerite. The petrochemistry of the rocks shows that the dolerite dyke is peraluminous with moderately high Al, Fe, Mg, and Ca contents compared to other rocks in the same area.
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 | 0.001 | 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".