Morphometric analysis of pebbles in verification of transport processes and interpretation of palaeoenvironment: A case study from the Ogwashi Formation (Oligocene), Niger Delta Basin, Nigeria

The present paper discusses a palaeoenvironmental interpretation of the Oligocene Ogwashi Formation (Niger Delta Basin, Nigeria) through morphometric analysis pebbles, research method essentially depending on quantitative evaluation pebble size and shape which change during transport processes in range depositional environments. relationship bivariate ternary-diagram plots independent functions was determined from freshly exposed sandstone sections quarries at Ibusa, near Asaba, Nigeria. grain pebbles ranges fine (11.00 mm) to very coarse (41.33 mm), with mean 21.05 mm (coarse pebbles). A plot flatness index vs maximum projection sphericity shows 37% fall within beach (marine) environment, 33% fluvial environment; remaining 30% are uncertain. oblate-prolate indicates that 47% marine environment 22% while 31% sphericity-form ternary diagram primarily comprise bladed, platy, bladed platy near-equal proportions minor elongate stones, suggests diverse origin. largely disc blade shapes number spherical rod shapes. proportion different segments plots, wide distribution sizes suggest is composed redeposited sediments likely were transported deposited mix settings possible transitional In other words, can be interpreted as marine-influenced marginal-marine settings.