Lithostratigraphyand Hydrogeology Of Gwandu Formation Exposed On Gulma Hill Near Argungu Northwestern Nigeria

Geological field mapping was carried out on the exposure of Gwandu Formation around Gulma Hill near Gulma village in the Sokoto sector of the Iullemmeden Basin to elucidate more on the interaction between rock types and their water source. Basic lithological characteristics including bed thicknesses, textural features, sedimentary structures, biogenic structures, and structural features were described. One lithostratigraphic section and a geological map were produced. Hydrogeochemical investigation was carried out in eight different locations in Gulma village near Argungu, northwestern Nigeria in order to determine the level of groundwater contamination. Eight groundwater samples were collected from the study area with their physico-chemical parameters such as electrical conductivity (EC), total dissolved solid (TDS), potential of hydrogen (pH), and temperature measured in situ. Both chemical and heavy metal analyses for the samples were conducted through the use of AAS machine. The results were used to plot the Schoeller and Piper diagrams which shows the dominant water type in the study area to be Ca-Mg-HCO3 type. The concentration of the analyzed metals in the study area shows that, Na2+and NO3-, have values that are within WHO (2022) safe limit, while Ni2+ is within the NSDWQ (2015) safe limit, physical parameters like TDS, and EC values fall within the NSDWQ (2015) safe limit. pH of some water sample fell below the recommended NSDWQ (2015) safe limit whereas pH of water samples from some areas are within the NSDWQ (2015) safe limits. However, Mg2+and Pb2+ have values above the NSDWQ (2015) recommended safe limits which suggest that the water could predispose consumers to health hazards..Standard procedures are highly recommended to remediate Mg2+and Pb2+in drinking water in the study areas.