Greener Journal of Physical Sciences

Greener Journal of  Physical Sciences  Vol. 3 (7), pp. 255-272, November 2013.  

ISSN: 2276-7851 © 2011 Greener Journals

Research Paper

Manuscript Number: 052713640

 

Palynostratigraphy, Age Determination and Depositional Environments of the Imo Shale Exposures at the Okigwe/Port Harcourt Express Road Junction Okigwe, Southeastern Nigeria

 

 

Durugbo Ernest Uzodimma

 

 

Department of Biological Sciences, Redeemer’s University Mowe, Ogun State, Nigeria.

 

Email: ernestduru @ yahoo.com; durugboe @ run.edu.ng

Abstract:

The palynological study of the shale exposures at the Okigwe-Port Harcourt Express Road Junction Okigwe, Southeastern Nigeria yielded moderate records of palynomorphs dominated by palm pollen Longapertites marginatus, L. vanendeenburgi, Mauritidites crassiexinus, Spinizonocolpites echinatus, Echitriporites trianguliformis, with abundant fern spores Deltoidospora adriennis, Cyathidites minor, common fungal spores, and sparse records of the dinoflagellate cysts Ifecysta fusiforma, Ifecysta heterospinosa, Phelodinium magnificum, P. africanum, Fibrocysta lappacea, Homotryblium tenuispinosum, Diphyes colligerum, Cerodinium spp., Ceratiopsis spp., Apectodinium spp., Kallosphaeridium spp., Cordosphaeridium spp., Exochosphaeridium spp., Spiniferites spp., Cleistosphaeridium spp., and Lejeunecysta spp. The sequences composed of alternating successions of brown to grey, soft to moderately hard, and fissile mudstones, with sand intercalations. Carbonaceous matter and ferrugineous materials were the accessory minerals. The recovered micro floral assemblages with abundant plant debris, sparse cuticles, common fungal spores suggests near-shore to marginal marine depositional environments. Published ranges of the palynostratigraphically important taxa enabled the delineation of the age as Middle Paleocene – Early Eocene thereby indicating that the exposure belongs to the Imo Formation. Again, the preponderance of palm pollen supports the Cretaceous – Early Tertiary palm province which traversed the southern hemisphere. The kerogen analysis revealed that the samples were immature for oil and gas generation.

 

Keywords: Okigwe, Imo Formation, palynomorphs, kerogen, phytoclasts.

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