MINERALOGY AND GEOCHEMISTRY OF THE ECONOMIC CLAY BEDS OF ASWAN AREA, SOUTHERN EGYPT

Details

Serval ID
serval:BIB_DCC7D213B4B6
Type
Article: article from journal or magazin.
Collection
Publications
Title
MINERALOGY AND GEOCHEMISTRY OF THE ECONOMIC CLAY BEDS OF ASWAN AREA, SOUTHERN EGYPT
Journal
Fifth International Conference on the Geology of the Tethys Realm, South Valley University, January 2010
Author(s)
E. S. Khedr , E. A.A. Youssef , A. A. Refaat , K. Abu Elmagd , H. M. Khozyem 
Publication state
Published
Issued date
2010
Pages
179-196
Language
english
Abstract
The studied sedimentary section at Aswan area (~ 170 m. thick) consists mainly of sandstone intercalated with six
clay beds. The section encloses nine stratigraphic formations, ranging in age between Cambrian and Paleocene, separated
by four unconformity planes. Two types of rock weathering, glacial and lateritic, are indicated. The upward increase of
alumina and iron oxide in Kalabsha weathering profile suggested lateritization in hot humid weather (tropical). Even as the
weathered profile east and southeast of the study area is a character of upward increases in the oxides of Si, Ti, Mg, and Na
accompanied with depletion in the oxides of Al, Fe, Mn, Ca, K, and P, the weathering processes could have been occurred
in very cold region. The economic kaolin SW of the study area are developed by weathering of the Precambrian crystalline
basement rocks. The contradiction in types of the weathering processes (very cold versus tropical condition) on the
crystalline Basement Rocks is attributed to changeability of different climatic zones in the study area during Paleozoic and
Mesozoic Eras.
The weathering zone in the basement is disconformably covered by the Cambrian Araba Formation east and
southeast of the study area. The Araba Formation is devoid of economic clay and unconformably overlain by the
Carboniferous Gilf Formation which consists of three clay-beds namely; lower, middle, and upper clay beds, all are in use
for ceramics industry. After deposition of the Gilf Formation in the study area, deep peneplanation prevailed and the
remnant of the Gilf Formation as well as the scoured surfaces of the basement crystalline rocks are subjected to
lateritization followed by deposition of the Abu Ballas Formation (Late-Jurassic-Early Cretaceous) which unconformably
overlies by Temsah Formation (Late Cretaceous) followed by Taref Formation, the Maastrichtian Qusier variegated shale
and Dakhla shale formations. Both Qusier and Dakhla shale are not in use for ceramics industry. The average size grade of
the economic clay beds of the Gilf Formation in Aswan area is the silty clay, while the shale beds of Qusier and Dakhla
formations are sandy-siltstone. There is a general upward increase in oxides of Fe, Si, Mg, Ca, and P from the older
Carboniferous clay beds of the Gilf Formation to the relatively younger Qusier and Dakhla shale deposits. However, the
sequence of the three economic shale-beds of Carboniferous age demonstrates upward enrichment in alumina and loss in
silica. This criterion is in harmony with the gradual rise in temperature of the regional climate in Egypt due to the northward
drift of Africa faraway from the Ordovician polar region into the equatorial region in Jurassic-Cretaceous times.
The most dominant clay minerals in the studied samples are kaolinite, illite, smectite, and regular stratified micamontmorilonite,
whilst the non clay minerals are represented by quartz as the most dominated mineral with subordinate
iron oxides (hematite, and goethite), calcioferrite, pyrite, calcite, gibbsite, and kleberite.
The economic clay beds of the Temsah Formation (Late Cretaceous) formed in area characterized by calm reducing
lake-water supplied by ephemeral meanders deriving their suspended loads from elevated land located to the north of the
studied Wadi Abu Aggag localities
Create date
09/08/2013 20:23
Last modification date
20/08/2019 16:01
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