The flood basalts nearby of the Fayoum oasis (Northern Egypt)

Norbert Brügge, Germany
Dipl.-Geol.

The Widan el Faras basalts (nearby of the Fayoun oasis) are to be found between the Oligocene Qatari Formation (below) and the Miocene Khashab Formation (above). The thickness of the basalts was measured between 20 and 35 m. The type locality of the Widan el Faras basalts is located at the Widan el Faras hills (upper area of the Gebel Qatrani). Petrographical and chemical investigations prove, that the basaltic flood originate from a tholeiitic magma (saturated with silica). This magma is climbed-up along a fissure during the Oligocene age. The basalt has a consequence of three different floods. The both first floods are lenses - like. The third flood is massive and freshly preserved. It forms an edge at the uppermost area of the Qatrani steep slope.

Further areas of flood basalts in north- and middle-Egypt are distributed. They are concentrated in the region of Cairo, are found however also in the Bahariya depression and western to southwestern of it.



Widan el Faras



basalt


Geomorhological structure

The Widan el Faras basalt quarries, 20 km southwest of Umm es Sawan, are considered the source of stone used on the mortuary temple floors and walls of 4 th and 5 th Dynasty (c. 2575 – 2323 BC) pyramid complexes.



Fayoum flood basalt area from space

 
                                                
                                    Stratigraphical positions





Down slidden basalt blocks



dito

 



 



Map of all basalt floods in the northern part of Egypt

Remarkable is the age of all basalt flows. The dates fluctuate between
32 and 23.5 Ma in the Oligocene age. It agrees with the dating of other subvolcanic and orthomagmatic-hydrovolcanic structures in the Gilf Kebir,
in the White and Black Desert as well as the Libyan Desert Glass location. All structures are placed on a line, which proceeds from southwest to northeast. Can we suppose here a connection between continental drifting and a Hot Spot?