Abstract Flow remnants comprising the Wadi Natash Volcanic Field lie 125 km ENE of Aswan, Egypt, along the boundary between the Nubia Formation and the Precambrian basement complex. Three flow units are separated by volcaniclastic sedimentary sequences. The chemical and stratigraphic data show that each flow unit belongs to the sodic-rich olivine alkali basalt series grading upward from alkali basalt through hawaiite to mugearite and culminating in benmorite or trachyte. K/Ar dates near 90 m.y. are corroborated by Late Cretaceous leaf imprints found in the intercalacted volcaniclastic sediments. The age of these volcanic rocks suggests that they are not directly associated with Red Sea rifting. Their alkaline nature may imply they were involved with a prerifting doming process. Alternatively these volcanic rocks may belong to the intraplate, bimodal alkali-olivine basalt suite unrelated to Red Sea rifting.
[1]
D. Falvey.
THE DEVELOPMENT OF CONTINENTAL MARGINS IN PLATE TECTONIC THEORY
,
1974
.
[2]
K. McDonald,et al.
Nubia Formation of Central Eastern Desert, Egypt--Major Subdivisions and Depositional Setting
,
1979
.
[3]
L. Shapiro.
Rapid analysis of silicate, carbonate, and phosphate rocks
,
1975
.
[4]
T. Irvine,et al.
A Guide to the Chemical Classification of the Common Volcanic Rocks
,
1971
.
[5]
A. Nairn,et al.
Two phases of Cretaceous—Tertiary magmatism in the eastern desert of Egypt: Paleomagnetic, chemical and k-ar evidence
,
1981
.
[6]
T. L. Wright.
Presentation and interpretation of chemical data for igneous rocks
,
1974
.