GEOPHYSICAL LABORATORY STUDY OF THE DEPOSITS OF THE BLACK SANDS OF ABU KHASHABA BEACH, ROSETTA DISTRICT, EGYPT.

Abstract

The present research work is considered as a part of the Nuclear Materials Authority comprehensive exploration and assessment program of the Egyptian black sands. This work deals essentially with the study of some physical properties of the black-sand deposits using geophysical laboratory methods. These methods included the electromagnetic conductivity, magnetic susceptibility and grumna-ray spectrometry. This work aims mainly to defme the most efficient geophysical technique that can be used to explore these deposits in the field. It aims also to establish a set of standard curves that can provide a reliable quantitative tool to determine the total heavy mineral content of unknown black-sand samples from their measured geophysical responses.

The various laboratory geophysical measurements were carried out on

416 samples represent the black-sand deposits of Abu Khashaba area (located in the extreme northwestern comer of the Nile Delta). Among these samples, 272 represent the surficial deposits, and collected from a total surface area of 2.4 km2 . The remaining 144 samples represent the subsurface deposits, and collected from the exploratory drilled boreholes in the area, with maximum depth of I 0 m. Results of the different measurements have been presented i.1 the fonn of contour maps and subjected to conventional statistical methods of analysis to facilitate and enhance their interpretation.

Qu alitati ve interpretation of the various contour maps and results of statistical analysis of the data indicated that the black-sand deposits in the studied area are distributive in a pattern of repetitional zones of high and low heavy mineral content; striking approximately in the east-west direction, more or less parallel to the present shore line.