Origin of the Qattara Depression, Egypt

Research Article| July 01, 1990 Origin of the Qattara Depression, Egypt CLAUDE C. ALBRITTON, JR.; CLAUDE C. ALBRITTON, JR. 1Institute for the Study of Earth and Man at Southern Methodist University, Dallas, Texas 75275-0274 Search for other works by this author on: GSW Google Scholar JAMES E. BROOKS; JAMES E. BROOKS 1Institute for the Study of Earth and Man at Southern Methodist University, Dallas, Texas 75275-0274 Search for other works by this author on: GSW Google Scholar BAHAY ISSAWI; BAHAY ISSAWI 216 Misaha Street, Dokki, Giza, Cairo, Egypt Search for other works by this author on: GSW Google Scholar AHMED SWEDAN AHMED SWEDAN 3Egyptian Geological Survey and Mining Authority, Salah Salem Street, Abbassiya, Cairo, Egypt Search for other works by this author on: GSW Google Scholar Author and Article Information CLAUDE C. ALBRITTON, JR. 1Institute for the Study of Earth and Man at Southern Methodist University, Dallas, Texas 75275-0274 JAMES E. BROOKS 1Institute for the Study of Earth and Man at Southern Methodist University, Dallas, Texas 75275-0274 BAHAY ISSAWI 216 Misaha Street, Dokki, Giza, Cairo, Egypt AHMED SWEDAN 3Egyptian Geological Survey and Mining Authority, Salah Salem Street, Abbassiya, Cairo, Egypt Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1990) 102 (7): 952–960. https://doi.org/10.1130/0016-7606(1990)102<0952:OOTQDE>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation CLAUDE C. ALBRITTON, JAMES E. BROOKS, BAHAY ISSAWI, AHMED SWEDAN; Origin of the Qattara Depression, Egypt. GSA Bulletin 1990;; 102 (7): 952–960. doi: https://doi.org/10.1130/0016-7606(1990)102<0952:OOTQDE>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract As a working hypothesis, we propose that the Qattara Depression originated as a stream valley that was subsequently dismembered by karstic processes during the late Miocene epoch and afterward was deepened by deflation and otherwise modified by mass wasting and fluviatile processes.The Depression is excavated in sedimentary rocks of Tertiary age that have a regional dip of a few degrees toward the Mediterranean Sea. The precipitous northern wall is the scarp slope of a cuesta capped by carbonate rocks of middle Miocene age. Its cliffy slopes descend to pediments graded southward to an axial valley. That valley, now extensively covered by saline crusts, sabakha deposits, and salt marshes, slopes westward into the deeper quadrangular part of the basin where elevations as much as 134 m below sea level have been measured. Nearby sinkholes and cavernous subsurficial limestone attest to past karstic activity. Presumably karstification reached a peak during the recession of the Mediterranean Sea late in the Miocene epoch when the north-dipping aquifers discharged into the then almost empty basin.As the Mediterranean Sea receded, what is now the Western Desert of Egypt and its off-shore continuations were subjected to extensive erosion by streams. A major stream issuing from the Gilf Kebir Highlands flowed northward to near the present site of Siwa Oasis, its alluvium now mostly covered by aeolian deposits of the Great Sand Sea. If it reached the Mediterranean Basin, then it may have done so through the Sahabi Channel System of Libya, or by a much shorter route through the Qattara area to an exit near the head of the Ras Alam er Rum submarine canyon offshore near Alexandria. In either case, the stream responsible for the Qattara cuesta, whether a tributary of the "Gilf River" or a part of that river's descending course into the Mediterranean Basin, apparently became inactive after its waters were diverted into underground courses through sinks and caverns. With the refilling of the Mediterranean and the accompanying diminution of subsurface aqueous activities and with the advent of more and climatic regimes, surface processes associated with deserts have completed the shaping of the Depression to give it its present configuration and character. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.