الفهرس 
Location Of Study AreaOnly 14 pages are availabe for public view
 |  | from | 286 |  |  |
| | | from | 286 | | |
Abstract
The qualitative and quantitative interpretations of the available
geophysical data (particularly gravity and electrical resistivity data) are
carried out in the study area to indicate subsurface geological inferences.
The area under study is located at Helwan, southeastern Cairo between
latitudes 29o46’ N & 29o50’ N and longitudes 31o21’ E & 31o25’ E.
The interpretations of the gravity data are done in the form of
separation of the regional and residual gravity anomalies, in which the
regional gravity anomalies reflect the deep seated geological effects and
the residual anomalies reflect the shallow seated geological effects. After
that the filtering of Bouguer gravity anomalies is carried out. This
technique is used to separate the residual anomalies from the regional
anomalies from the anomalies existed within a certain interval of depth. It
is also beneficial in attenuating the extraneous factors affecting a certain
depth range and enhancing the wanted effects of the other depth ranges.
In addition, trend analysis is applied on the results of discriminating the
faulting picture at successive levels (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0,
4.5 & 5 Kilometers) to determine the fault systems dissecting the
sedimentary section and the basement complex. Accordingly, the major
tectonic trends are mainly oriented NNE-SSW, NW-SE, NNW-SSE,
ENE-WSW & NE-SW in decreasing orders. Finally, the depths to the
basement are determined and ranging between 1.9 km & 3.2 km.
Ten vertical electrical soundings in addition to seven dipoledipole
profiles are conducted in Helwan limestone quarry. On the other
hand, fifteen vertical electrical soundings are conducted in Helwan clay
quarry. These measurements are done to know the detailed information
about the source and extension of the water seepage on the floor of
III
quarries. In Helwan clay quarry, the results suggest passage of
groundwater from the adjacent areas via channel ways formed due to the
excavation process. All over the measured area, there are some sand
lenses intercalated with clays & during the excavation process, some
channels formed and the groundwater started to percolate through these
channels forming many water pools along the quarry floor. On the other
hand, in Helwan limestone quarry; the results suggest passage of
groundwater from the adjacent areas via channel ways formed due to
reopening of the fissures and cracks in the fault zone. The fissures are a
direct consequence of maximizing explosive quantities, groundwater
percolates through the new rock openings in the fault zone from the
source at the NW direction of the quarry to the lower level in the quarry
floor.