Economic geology is the branch of geology that is concerned with the study and analysis of earth materials, deposits or resources that are very useful or profitable to man.
In the study area, deposits of economic importance were seen during the mapping exercise. This deposits of economic importance led to the establishment of Nigercem in the area which is the first indigenous cement manufacturing industry in the country. This has helped to promote the industrial development and standard of living of the inhabitants of the study area.
The deposits of economic importance can be explained as follows.
LIMESTONES ON ECONOMIC GEOLOGY
This is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal form of calcium carbonate (caco3).
Limestone the principal raw materials for the production of cement are universally important and of great economic value.
However, many geologists and District officer of the NIGERCEM quarries have proved existence of ample deposits of good quality limestone within the study area. This has resulted to the establishment of NIGERCEM industry in the area and has also made quarrying of limestone the chief occupation of inhabitants of the area.
Amongst the variable uses of Limestone are the following.
I. Cement production
II. As a building material
III. As aggregate to form the base of roads
IV. Manufacturing of fertilizers
V. Removing of impurities from metals in metallurgical industries
VI. Refractory Lining
VII. Non metal smelters and Flux in electrical industries.
VIII. As white pigment or Filler in products such as toothpaste or paints.
Research has been carried on the possible Utilization of shales of the study area by determination of its plasticity and air drying shrinkage (Ogbukagu, 1982). He observed from the analysis that the shales of the area exhibit low shrinkage and suggested that it could be use in making foundation bricks. Hence, it serves as construction material for mud houses.
HYDROGEOLOGY OF THE STUDY AREA.
Hydrogeology is a branch of geology that is concerned with the study of water-bearing rocks, the chemistry, physics and movement of groundwater and the laws governing groundwater movement.
During this study, the area was discovered not to contain aquiferous geologic formations that are capable of yielding significant quantities of water.
No aquifer formations were observed but the geologic formations (shale and limestone) seen in the area were noted to be aquicludes which do not yield economic quantity of water.
Although, Ofomata (1975). Highlighted that the zones of saturation in the Cretaceous rock of the Cross-River plains were noted to be shallow but the rocks are impervious hence aquiclude. And he also noticed that groundwater resources in this plain are poor. These findings of Ofomata (1975) are what happened in the study area.
- Surface source (Rivers, streams, ponds)
- Underground source
SURFACE WATER SOURCES
In the course of this work, abandoned mining pits of the NIGERCEM industry is one of the major source of surface water to the people of the area.
The mining pits due to its large and depth in size is capable of retaining water throughout the year and it is used by the people for economic purposes. The minor rivers in the study area are Uzoru, Ogbeagu Rivers while the major one is the Ebonyi River. Most of these surface sources of water in the area are ephemeral in water supply like the Ogbeagu river only lasts during rainy season and dries up during dry season.
The surface water in this area is found to carry heavy loads of suspended material and dissolved elements emanating from run off. The effect of this is that it makes the water unsafe for human consumption and also does not form lather easily with soap or detergent due to high level of dissolved elements.
Rain water from the atmosphere serves as a good recharging agent to the water resources of the area. The rain water is the most available to the people during the rainy season.
The ground water supply in the mapped area is very poor which is because of the impervious limestone and shale that is underlies the study area.
Detailed study of the area suggests that ground water exists in four zones.
In fractured zone of ASU-River and Ezeaku formation
In weathered zone
In sediment intrusive boundaries.
There is also the availability of groundwater in minor joints, fissures and cracks.
This water was found to exist in form of groundwater in the above mentioned zones and areas. This work hereby recommends these zones as areas of best interest in the exploration for groundwater in the study area. The water from the ground source is made available to the surface through boreholes and hand dug wells.
Information from Ebonyi State Rural water supply and Sanitation Agency (EB-RUWASSA) which is the organization that drills the boreholes in the study area indicates that the depth of borehole in the study area ranges from 30-46m and state water level of the area ranges from 4.4-10.5m.
However, most of the drilling program carried out in the area proved abortive due to the impervious nature of the underlying lithologies.
Solution cavities have been reported at a depth of 558ft below sea level. This suggests a great probability of locating larger solution cavities below the depth investigated by de sward et al (1950). This solution cavities is the zone where ground water can be found in the area underlain by limestone due to it impermeable nature. While in the area underlain by shale, water was found along the joint between them (de sward t et al, 1950).
In all, due to inadequate water supply in the area, government should site more boreholes for the people and as well ensure that proper geophysical survey are carried out on the area before drilling the boreholes.