SOURCE IDENTIFICATION AND VARIATION IN THE CHEMICAL COMPOSITION OF RAINWATER IN THE COASTAL AND INDUSTRIAL AREAS: A CASE STUDY OF IKOT ABASI, SOUTH-EASTERN NIGERIA

[摘要] A systematic geochemical investigation of the Laki Formation from the selected regions of Southern IndusBasin Pakistan Basin has been carried out. This paper presents the characterization of hydrocarbon potential,type of kerogen, thermal maturity, the origin of organic matter, depositional environment, and bulkmineralogy of the Laki Formation shales. The total organic carbon (TOC) content of the Laki shale rangesfrom 0.53 to 2.66 wt. %. The values indicate that Laki shales have fair to very good hydrocarbon potential.Type III kerogen is identified in the Laki shale based on TOC and residual potential (S2) data. Maturityparameters (Tmax & Methyl phenanthrene index) suggest that Laki shales are thermally immature for thegeneration of hydrocarbons. Normal alkane data and stable carbon (δ13C) isotopic value (-9.67 ‰ PDB) ofthe Laki shale indicates the predominantly marine origin of the organic matter.Dibenzothiophene/phenanthrene (DBT/P) ratio (0.08), Phytane (Ph)/n-C18 versus Pristane (Pr)/n-C17, andPr/Ph versus DBT/P data suggest a marine environment of the Laki shale. The marine setting of the LakiFormation shale is further evident by coralline algae and Alveolina oblonga. X-ray diffraction (XRD) datareflect that Laki shale is brittle since it is dominated by high quartz and carbonates.

[学科分类] 地球科学(综合)

[关键词] Rainwater;Enrichment Factor;Anthropogenic Activities;Neutralisation Factor;Acid Potential