Pebble morphogenesis of the Cretaceous Conglomerates from the Abeokuta Formation near the Oluwa River, Eastern Dahomey Basin, Southwestern Nigeria

Authors

  • Dr. Oladotun Afolabi Oluwajana Adekunle Ajasin University, Akungba-Akoko, Nigeria https://orcid.org/0000-0003-1518-559X
  • Dr. Charles Ugwueze Department of Geology, University of Port Harcourt, Port Harcourt, Nigeria
  • Dr. Ovie B. Ogbe Department of Earth Sciences, Federal University of Petroleum Resources, Effurun, Delta State Nigeria https://orcid.org/0000-0002-4615-8677
  • MSc. Kehinde Egunjobi Department of Geology, University of Ibadan, Ibadan, Nigeria https://orcid.org/0000-0002-6846-6312

DOI:

https://doi.org/10.17794/rgn.2021.5.9

Keywords:

Cretaceous, paraconglomerate, pebble morphometry, depositional processes, Abeokuta Formation, Nigeria

Abstract

Pebbles taken from the bed of the Cretaceous Abeokuta Formation paraconglomerate near the Oluwa River were used to infer the depositional setting and the nature of the source area, through the integration of bivariate and ternary (sphericity-form and Zingg diagrams) analyses. Deposition in a river environment is indicated by the high sphericity values, ranging from 0.59 to 0.88 (average 0.70). Also, bivariate plots of the maximum projection sphericity (ψp) vs. oblateprolate index (OPI) and flatness index (FI) vs. maximum projection sphericity (ψp) point to the domination of fluvial processes. Dominantly elongated, compact elongated, compact and compact-bladed pebbles are typical for sedimentary regime with prevalence of fluvial over beach processes. Co-existence of various pebbles shapes (mainly disc, rod-, and sphere-shaped), despite of the similar, predominantly quartz composition, may occur due to the different clast fabrics. This heterogeneity also indicates various transport distances and water energies, pointing to the multiple source areas.

Author Biographies

  • Dr. Charles Ugwueze, Department of Geology, University of Port Harcourt, Port Harcourt, Nigeria

    Senior Lecturer,

    Department of Geology,

    University of Port Harcourt,

    Choba, Nigeria

  • Dr. Ovie B. Ogbe, Department of Earth Sciences, Federal University of Petroleum Resources, Effurun, Delta State Nigeria

    Lecturer,

    Department of Earth Sciences,

    Federal University of Petroleum Resources,

    Effurun, Delta State Nigeria

  • MSc. Kehinde Egunjobi, Department of Geology, University of Ibadan, Ibadan, Nigeria

    Graduate (Research) Student,

    Department of Geology,

    University of Ibadan, Ibadan, Nigeria

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Published

2021-11-24

Issue

Section

Geology

How to Cite

Pebble morphogenesis of the Cretaceous Conglomerates from the Abeokuta Formation near the Oluwa River, Eastern Dahomey Basin, Southwestern Nigeria. (2021). Rudarsko-geološko-Naftni Zbornik, 36(5). https://doi.org/10.17794/rgn.2021.5.9