Ekwenye, Ogechi

The Paleogene strata of south-eastern Nigeria include the Imo Formation, Ameki Group and the Ogwashi Formation, which are collectively referred to as the outcropping Niger Delta succession and their ages range from Paleocene to Oligocene. This research involves the study of outcrops and borehole data for facies analysis, ichnology, palynology, clay mineralogy, petrology and heavy mineral analysis in order to reconstruct the paleogeography of the Paleogene period, develop new depositional models and re-interpret the depositional environments of the Paleogene strata. The results provide a new depositional environment for the lower Sandstone Member of the Imo Formation - tidal sandwave deposit and a new paleogeographic model for the Imo Formation. Improved facies and sequence stratigraphic models are developed for the deposits of the Ameki Group and these sedimentary deposits are re-interpreted as tide-dominated estuarine system. Novel depositional facies are produced for the Ogwashi Formation and the strata are also re-interpreted as tidally-influenced coastal plain deposit. Furthermore, the sand body geometries, their spatial distribution and continuity as well as the sandstone heterogeneities of representative outcrops of these formations are well documented in this research. Results from heavy mineral analysis suggest mixed provenance for the Paleogene sediments; the primary sources are polycyclic pre-existing sedimentary rocks, magmatic-gneiss complex and granitic rock of the Oban Massif and the magmatic-gneiss complex and the schist belt of the Western Nigerian Massif. This study proposed possible factors controlling the distribution of the heavy mineral suites in the Paleogene sediments to include river influx, tide and wave actions and hydraulic sorting. Four type-1 stratigraphic sequences, consisting of lowstand systems tracts and/or transgressive systems tracts and highstand systems tracts have been established for the depositional succession of the Paleogene strata. This detailed sedimentological research on the Niger Delta provides a new insight into the study of shallow marine environments. <br/

Royal Holloway - Pure

Facies architecture, sedimentary environment and paleographic evolution of the Paleogene stratigraphy, South Eastern Nigeria

https://pure.royalholloway.ac.uk/ws/files/24385999/2014ekwenyeocphd.pdf

Facies architecture, sedimentary environment and paleographic evolution of the Paleogene stratigraphy, South Eastern Nigeria

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Royal Holloway - Pure