الفهرس 
CHAPTER I: Introduction.Only 14 pages are availabe for public view
 |  | from | 202 |  |  |
| | | from | 202 | | |
Abstract
The present paleomagnetic research was carried out on two distinct rock-units well-exposed in Central Egypt within the Minia Governorate. The Late Ypresian “Minia” formation limestone, which represents the oldest rocks exposed in the area as well as the youngest rock-unit represented by the Late Oligocene basaltic eruptions which pierce through all the Middle Eocene limestone and have K/Ar ages ranging between 22-28 Ma as well as 39Ar/ 40Ar age of 23 Ma, were paleomagnetically studied. The ultimate goals of this research was to shed light on the paleotectonic positions of Africa and the paleolatitudes of northeast Africa upon the end of the Early Eocene and during the Late Oligocene, then decipher the latitudinal changes of Africa during this time span.
In order to achieve these themes, three widely-separated sections of the “Minia” formation were, initially, collected and their anisotropy of magnetic susceptibility [AMS] was inspected, in order to confine the paleomagnetic sampling to the virtually isotropic limestone beds. The subsequent stepwise thermal demagnetization of the three-axis isothermal remanent magnetization [IRM] acquired in one sample/ site, revealed that magnetite is the main remanence carrier, in most samples, with a limited contribution of goethite and/or hematite.
On the other hand, the basaltic rocks which are represented by two chemically differentiated varieties; the normal basalt and the basaltic andesite, erupted along major parallel NW-SE fractures in the Eastern and Western Deserts in Central Egypt, were sampled, at nine widely-separated clusters using a solar compass. The stepwise acquisition of the [IRM] and its subsequent stepwise thermal demagnetization revealed that the dominant remanence carriers of the remanent magnetization in most sites are magnetite/ titanomagnetite mineral phases with minor contribution from goethite and/or hematite.