MINERALOGICAL COMPOSITION OF LIGNITES IN PARTS OF SOUTHEASTERN, NIGERIA.

Abstract

The present study is focused on characterization of lignites in the Eocene – Pliocene Sedimentary successions of the Niger delta region. The lignites are collected from river/stram channels and from Borehole ditch Cuttings. A total of Eleven (11) Lignite samples from nine (9) locations were analyzed using the XRF, XRD, SEM- EDS analytical methods.  The Geochemical result indicates that all the lignite have high silica (SiO2) in the range of 25.43  ̶  83.55 wt% and alumina (Al2O3) 9.909  ̶  23.519wt%, with low MnO, CaO, MgO, and K2O indicating their continental origin. Mineral constituents found in the lignites are dominated by Quartz, orthoclase, clay minerals (Kaolinite, Nacrite, Osumulite, and Illite) in association with heavy mineral Garnet. Graphite was identified in L21, Unit5 and Unit9 respectively. The SEM ¬ EDS shows that the lignites contains Carbon C ranging from 29.29 ¬ 63.52wt % , Oxygen O2 45.76 ¬ 22.51 and Si 12.88 ¬ 4.83wt% of elements, while L16 is rich in Bromine, Sulphur, Casium and Silver. The ratios of sensitive element (V/Cr, V/V+ Ni,) and major oxides ratio (CaO +MgO +Fe2O3)/(SiO2 +Al2O3) from the analyzed samples indicate a terrestrial, reductive (oxic) conditions which are characteristics of paludal lacustrine environment.