Geology and Geochemistry of Sedimentary Manganese Ore in Upper Strata of Shendi Formation, River Nile State, Sudan

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Year:
2022
Type of Publication:
Article
Keywords:
Manganese, Nodular, Shendi Formation, Textures
Authors:
Sadam H. M. A. Eltayib; Abu baker A. M. A. Abasher
Journal:
IJRIES
Volume:
9
Number:
1
Pages:
1-12
Month:
January
ISSN:
2394-1375
BibTex:
Abstract:
This paper presents the results of geological and geochemical study of sedimentary manganese ore from surface strata of the Shendi Formation, River Nile State, Sudan. The main geological units in the study area are composed of Basement Complex (Pre-Cambrian), Nubian sandstone formation (upper Cretaceous), Hudi Chert (Oligocene) and Quaternary superficial deposit in ascending chronological order. The aims of this study are to investigate the geological behavior and geological conditions affecting precipitation of sedimentary manganese ore. The methodologies have been used to realize the objectives of this study included; field work, office work and labrotary work include thin sections, polished sections and chemical analysis. According to field observation sedimentary manganese ore can broadly be considered as occurring in three major classes: Fine grain manganese, nodular manganese and crust form manganese. The modes of occurrence of manganese ore was described at the outcrops and vertical sedimentary profiles revealed that the manganese occurred in study area at different types in stratigraphic sequence such as cap, beded and interbeded conformable with Shendi Formation. Petrographic study of manganese ore in collected samples using polarized microscope and ore microscope includes study of the textures and structures of ores to obtain ore history. The main types of textures and structures in studied samples are nodular, granular and massive. Geochemical investigation of studied samples includes chemical analysis of trace element (Cr, Co, Cu, Zn, Mn and Ni) using Atomic Absorption Spectrometry (AAS). Manganese ore in study area ranging between Maximum 11659.7 ppm in Elnagaa1 area to Minimum 216 ppm in Alnagaa3 area and the average is 2985.35 ppm. According to these results the origin of manganese ore is formed by chemical precipitation during chemical weathering of surrounding areas in continental lacustrine environment.