Browsing by Author "Chukwuma-Orji, Jacinta Nkiru"

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Access status: Open Access ,
A palynology and paleoenvironmental study of a section from the Amansiodo-1 well, Anambra Basin, southeastern Nigeria
(Wydawnictwa AGH, 2017) Chukwuma-Orji, Jacinta Nkiru; Okosun, Edward Agboneni; Ekom, Joseph Clement; Abolarin, James Femi
Palynological analysis was carried out on twenty (20) ditch cutting samples from a section (1284.73–1496.57 m) of the Amansiodo-1 well, Anambra Basin, southeastern Nigeria with the aim of determining the age, biozone, and depositional environment of the sediments within the depth interval. The laboratory techniques of digesting sediments in hydrochloric and hydrofluoric acids for silicates and carbonates removal were followed to process the samples for the recovery of palynomorphs. Fifty two (52) palynomorph specimens were recovered. An assemblage zone of Echitriporites trianguliformis Zone has been established. The section was dated to the upper Maastrichtian due to the occurrences of age diagnostic marker species such as: Cingulatisporites ornatus, Distaverrusporites simplex, Proteacidites sigalii, Dinogymnium cf auclaense, Echitriporites trianguliformis and Retidiporites magdalensis. Based on the palynomorph marine index and environmental indicator flora, the section was inferred to be deposited in marine to brackish (coastal) environments with little influence of fresh water.
Access status: Open Access ,
Palynofacies analysis of Ida-4 well, Niger Delta Basin, Nigeria
(Wydawnictwa AGH, 2019) Chukwuma-Orji, Jacinta Nkiru; Okosun, Edward Agboneni; Gana, Funmilayo Daramola
Palynofacies analyses of the strata penetrated by Ida-4 wells were carried out with the aim of studying the stratigraphic sequence penetrated by the well in order to establish palynostratigraphic zones, relative age and the paleoenvironment of deposition. Fifty ditch cutting samples within the interval of 2179–3523 m were analyzed. The acid methods of sample preparation for palynofacies analyses were followed. The result of the analyses yielded low to abundant occurrences of pollen and spores with an abundance of small, medium and large sizes of palynomacerals 1 and 2, few occurrences of palynomacerals 3 and 4. The lithology consists of the alternation of shale and sandstone units with few intercalations of argillaceous sandstone units, indicating that the studied interval belongs to the Agbada Formation. The studied intervals were dated to the middle Miocene to late Miocene, based on the recovered age diagnostic marker species such as Zonocostatites ramonae, Multiareolites formosus, Verrutricolporites rotundiporus, Crassoretitriletes vanraadshoveni and Racemonocolpites hians. Two interval range palynostratigraphic zones: Multiareolites formosus – Zonocostatites ramonae, Verrutricolporites rotundiporus - Crassoretitriletes vanraadshoveni and a taxon range zone: Ainipollinite verus zone were proposed. Paleoenvironmental interpretation was based on the palynofacies association and the lithology which revealed that the stratigraphic interval studied was deposited in the Coastal-deltaic (marginal marine) environments.