OFULUME A. B.^1,, IBE K. K.¹, IBENEME S. I.¹, DIOHA E. C.¹, CHINEMELU E. S.², ELUWA J. C.³, ONYEISE U.O.¹

The Ndi-Uduma Ukwu/Ohafia-Ifigh limestone deposit is located approximately 55km East of Umuahia and about 125km Northwest of Calabar, S.E. Nigeria. This coarse grained, light to dark grey limestone is sandwiched between two carbonaceous highly fissile shale units of the Nsukka Formation forming shale-limestone-shale sequence. Outcrop samples were utilized in the petrographic investigation and geochemical analysis using Atomic Absorption Spectrophotometer (AAS). The calcium carbonate content (% CaCO₃) of the limestone ranges from 65.08 to 82.41%. The samples from Ohafia-Ifigh are SO₃-free and purer while the Ndi Uduma Ukwu had MgO and SO₃ content of 3.34 and 1% respectively. Petrographic analysis of the limestone reveals a highly fossiliferous limestone infilled with chiefly sparry calcite with micrite envelope, consisting of foraminifera, ostracod, echinoid, bivalve gastropod, coralline algae suggestive of shallow marine environment. Although the limestone does not compare with that of Shapfell, UK and Mfamosing S.E. Nigeria in chemical purity to warrant lime production with it, yet it meets some industrial raw material specification such as for cement, agriculture and poultry applications.

Geochemistry, Lime, Limestone, Ohafia, Petrography