Geochemical characterization and palynological studies of some Agbada Formation deposits of the Niger Delta basin: implications for paleodepositional environments

Abstract

Forty-two ditch cutting samples of the KR-1 offshore well from depths of 9660 ft to 10,920 ft composited at 90-ft intervals were subjected to sedimentological, micropaleontological, and geochemical analyses using standard procedures and the laser ablationinduced coupled plasma mass spectrometry technique, respectively. Sedimentological analysis revealed the presence of glauconites and the rare occurrence of framboidal pyrites, indicative of deposition in a slightly anoxic marine environment. Palynomorph percentage distribution shows that there are more terrestrially derived miospores (dominated by Zonocostites ramonae (Rhizophora spp.), Psilatricolporites crassus (Tabernaemontana crassa), Acrotichum aureum, and Laevigatosporites sp.) than marine phytoplanktons. Rare occurrence of Globoquadrina venezuelana, Globigerinoides promordius, and Globigerina sp. denotes an Early Miocene age and proximal shelf. These indicate that the main environment of deposition in the KR-1 well is coastal to marginal marine consisting of coastal deltaicinner neritic, made up of tidal channel and shoreface deposits. Geochemical results show that the average concentrations of considered rare earth elements are less than their concentrations in world average shale. Trace metal ratios (such as Th/Cr, Cr/Th, Th/Co, and Cr/ Ni) suggest that the investigated sediments were derived from felsic source rocks. Rare earth element patterns (such as La/Yb, Gd/Yb, La/Sm, and Eu/Eu) and Th data established the felsic composition of the source rocks. Ratios of U/Th, Ni/Co, Cu/Zn, and V/Sc suggest a well-oxygenated bottom water condition. Estimated europium and cerium anomalies of the studied samples suggest an oxidizing environment of deposition. Nonetheless, the ratios of V/Cr suggest a range of environmental conditions. Moreover, ratios of V/(V+Ni) suggest the rare occurrence of suboxic to anoxic environments of deposition.

Environmental pollution loads on surface water chemistry and potentially ecological risks of inland aquatic ecosystem in South-Eastern State, Nigeria

“…The findings were related to that of Agudozie et al (2019) who reported 15-30 mgL −1 in surface water of Nworie River. Accordingly, the mean value of Chloride in the present study is higher than 1.70 ± 0.279, 4.68 ± 0.300, 2.20 ± 0.78, 4.79 ± 0.222 obtained in Otamiri River, Imo State, Nigeria (Adebayo et al 2016), less than the observations of Oluyemi et al (2010a, b), and Ogwo et al (2014) who observed high values of chloride to be from 82-92 to 3.64-184.04 mg/L −1 in rivers.…”

Health Risk Evaluation of Trace Elements in Geophagic Kaolinitic Clays within Eastern Dahomey and Niger Delta Basins, Nigeria

“…The limit of detection (LOD) and limit of quantification (LOQ) for each element in mg kg −1 were 0.015 and 0.20, 0.148 and 1.99, 0.011 and 0.23, 0.101 and 1.52, 0.130 and 1.56, 0.004 and 0.06, and 0.008 and 0.11 for V, Cr, Cu, Ni, Zn, Pb, and Co, respectively. The analytical procedures and processing followed those described by Adebayo et al [ 35 ]. Glitter software [ 36 ], distributed by Access Macquarie Ltd., Macquarie University, New South Wales, was used for data processing.…”

Blooming of a microbial community in an Ediacaran extreme volcanic lake system

“…Furthermore, and as previously stated, the Amane Tazgart samples are characterized by high EF values for Cu, Zn, and U (Supplementary Table 5 ), which means that the Cu/Zn ratio can be used as a redox proxy for both the epiclastic and carbonate deposits. The Cu/Zn ratio is proposed as a valid proxy for ancient redox conditions 26 , 60 – 62 . In reducing environments, the precipitation of Cu is favored over Zn, while they have about the same solubility in oxidizing environments.…”