LABORATORY AND FIELD INVESTIGATIONS OF A VARIANT OF THE TWO-ELECTRODE D.C. RESISTIVITY ARR

Simple item page
dc.contributor.authorMAKINDE, VICTOR
dc.date.accessioned2014-02-21T10:13:48Z
dc.date.available2014-02-21T10:13:48Z
dc.date.issued1996-01
dc.descriptionA THESIS SUBMITTED TO THE DEPARTMENT OF PHYSICS, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF DOCTOR OF PHILOSOPHY IN GEOPHYSICS JANUARY, 1996en_US
dc.description.abstractThe present work has considered the application of a variant of the two-electrode array to the detection of, and prospecting for horizontal layerings within the earth. The mode of this two-electrode array makes use of only the two current electrodes without the potential electrodes. In its use, the electrode separation is varied by moving the two current electrodes equidistantly away from the sounding point. The result of this is that the current I, delivered by the power source through the earth also changes. The driving potential as indicated by the source voltage indicator was taken as the voltage developed across the section of the earth between the two current electrodes. In investigating the capability of this technique, called the C-C mode, in delineating horizontally-layered media, a laboratory experiment was set up. Different materials such as water - an electrolyte, lateritic clay, river sand and mixed-soil (a mixture of lateritic clay and river sand) were experimented for the one-layer (overburden) case. The experiment was conducted at various frequencies within the operating frequency range of the tank. All the frequencies used, including 0 Hz and 50 Hz, gave good alignment of the resisitivity point for all the materials and combinations used. The lateritic clay, river sand and mixed-soil were again variously combined to form two-layer and three-layer cases, all underlain by the non-conductive perspex as "basement". Graphs were plotted to show the variation of the "bulk resistivity" with the electrode separation (or its reciprocal). The most direct and easily interpretable results was given by the graph in which the "bulk resistivity" (b was plotted against the electrode separation AB/2 on a log-linear scale. The accurate delineation of the layers in the laboratory investigation encouraged the initiation of the field study. The Kubanni River Basin was chosen as the field study area. The basin occupies the centre of the South-Eastern sector of the Zaria sheet (No. 102 S.W.) of the 1:50,000 sheet ordinances series of the Nigeria ordinances survey map, with an average area of about 150 km2. It is underlain by Precambrian rocks of the Nigerian Basement Complex comprising mostly of older granites and biotite granite-gneiss overlain mostly by superficial deposits recognised by their brown cellular aspects. In carrying out the field investigations, thirtyone soundings were made in twenty-three stations using conventional Schlumberger VES method and the expanding C-C technique. Depth horizontal profilings were also carried out in one of the twenty-three stations and one other independent station using the Wenner array and the constant spacing C-C mode of the two-electrode array. Typical graphs as done for the laboratory model studies were plotted and deductions made. Results from the interpretation of the collected data using the C-C mode show that the depth to basement within the basin varied from about 7.9 m to about 36 m on the average. The result at each sounding location was compared with the interpreted result of the collected data using either the Schlumberger array or the Wenner array as the case may be. The layer delineation by the C-C mode agreed well with that delineated by the Schlumberger array. The C-C technique has delineated layers and has also given a good estimation of the layer thickness and an uncomplicated way of determining the surface layer resistivity.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/2286
dc.language.isoenen_US
dc.subjectLABORATORY,en_US
dc.subjectFIELD,en_US
dc.subjectINVESTIGATIONS,en_US
dc.subjectVARIANT,en_US
dc.subjectTWO-ELECTRODE,en_US
dc.subjectD.C.,en_US
dc.subjectRESISTIVITY,en_US
dc.subjectARRAYen_US
dc.titleLABORATORY AND FIELD INVESTIGATIONS OF A VARIANT OF THE TWO-ELECTRODE D.C. RESISTIVITY ARRen_US
dc.typeThesisen_US
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
LABORATORY AND FIELD INVESTIGATIONS OF A VARIANT OF THE.pdf
Size:
18.88 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.58 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
SCIENCE