COMPARISON OF CORE CONTROL AND GEOPHYSICAL INVESTIGATIONS, SILICA SAND DEPOSITS, DAWMAT AL JANDAL, AL JAWF AT SAUDI ARABIA BY GHASSAN SALEM ALSULAIMANI

This thesis is a summary of a comprehensive geophysical investigation in southern Dawmat Al Jandal, Al Jawf in Saudi Arabia. This research demonstrates that the acquisition of both core control and geophysical data is superior to the acquisition of core control alone. Coring is expensive and is limited in subsurface coverage. Geophysical surveying, however, is a relatively rapid and cost-effective means of deriving information about the subsurface between core holes. Ground penetrating radar (GPR), Multichannel Analysis of Surface Waves (MASW), and Seismic Refraction methods were used as exploration techniques to locate surficial mineral deposits within the study area.

During the course of these investigations, the author tries to review the acquired 1620 meters of ground penetrating radar (GPR) data to image internal reflections (if any) within the sand and the top of the underlying sandstone; 27 MASW field records were acquired at each core hole location, which generated 1-D and 2-D shear wave velocity profiles, and 27 seismic refraction profiles were acquired, which did not image the top of the sandstone. The purpose was to estimate the thickness of the sand and to map bedding planes within the sand to better understand depositional environments under the same conditions, based on the high-resolution 2-D surveys, mostly performed in mining areas.

The Geophysical investigations were successful and proved to be useful methods for the exploration of shallow subsurface areas where the results are equal to, or slightly different from, the corresponding with of the core holes’ values. Therefore, geophysical surveying does not remove the need for core control, but when it is properly applied it can optimize exploration rating programs by maximizing the rate of ground coverage and minimizing the amount of core drilling that is required.