الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 102 |  |  |
| | | from | 102 | | |
Abstract
The lithostratigraphy of the study area belongs to the post- Miocene Plio-Pleistocene . Eight sections were measured and described in the field. These sections are I, II, III, IV V, VI, VII and VIII . Several features and observations were recorded.
Lithostratigraphic section I to section VII belong to the Plio-Pleistocene paleosols where as section VIII belongs to non-clastic Miocene sediments.
the cumulative curves of the studied sediments curves show almost similar trend, exhibiting a dominance of sand and gravel sizes which makes the saltation and traction population is the most predominant in most of these curves.
The sorting coefficients of most of the studied samples indicate poor and very poor sorting, except those of section VI signify moderately sorting. This fact may be related to the limited extent weathering and short distance of transportation.
The studied sediments have mesokurtic, leptokurtic and, less commonly, platykurtic distribution patterns.
The studied sediments were transported and deposited mainly by fluviatile processes. This is indicated by: (i) the nature of their cumulative curves which indicate that their transportation was dominated by saltation and traction; and (ii) the plotting of the relationships between their grain-size parameters into the river fields of the applied scatter diagrams. This is further confirmed by the fact that their cumulative curves are similar to those characteristic of fluviatile sediments.
The foregoing discussion revealed that the studied paleosols are represented mainly by quartz arenite and rarely by polymictic conglomerate with intercalation of intrasparite. The detrital fractions of these rock types are dominated by quartz with rare chert and very rare feldspars and clay minerals. Most of the quartz grains are monocrystalline displaying unit extinction. Some quartz grains are polycrystalline or monocrystalline with undulose extinction. Clay minerals are dominated by montmorillonite with subordinate amounts of kaolinite.
These observations indicate the great similarity between the mineral composition of the studied paleosols and those of the nearby fluviatile sands and gravels. So, these sands and gravels constitute the provenance of the studied paleosols. This provenance may be passed through more than one cycle of sedimentation (i.e. high maturity), hence, its daughter sediments (paleosols) are highly mature. On the other side, the studied samples show low matrix content and nearly high roundness (high maturity) which again confirm the results obtained from the compositional characteristics of the studied samples. The intrasparite intercalation may be considered as a duricrust of calacrete type formed by the effect of raised water table of groundwater. This fact is evidenced by the occurrence of fresh water isopacheous calcite cement, absence of marine skeletal grains and abundance of terrigenous allochems similar to those recorded in the studied quartz arenite. The recorded abundant montmorillonite may be referred to alteration of basalt outcrop in the study area. The unstable minerals (olivine and pyroxene) of basalt are easily altered to montmorillonite under neutral to alkaline pH by the effect of moderate weathering. Kaolinite may be produced by the hydrothermal alteration of other aluminosilicates.