Geochronologic and isotopic evidence for involvement of pre-Pan-African crust in the Nubian shield, Egypt

Abstract

Research Article| August 01, 1990 Geochronologic and isotopic evidence for involvement of pre-Pan-African crust in the Nubian shield, Egypt Mohamed Sultan; Mohamed Sultan 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130 Search for other works by this author on: GSW Google Scholar Kevin R. Chamberlain; Kevin R. Chamberlain 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130 Search for other works by this author on: GSW Google Scholar Samuel A. Bowring; Samuel A. Bowring 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130 Search for other works by this author on: GSW Google Scholar Raymond E. Arvidson; Raymond E. Arvidson 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130 Search for other works by this author on: GSW Google Scholar Hassan Abuzied; Hassan Abuzied 2Department of Geology, Faculty of Science, Cairo University, Cairo, Egypt Search for other works by this author on: GSW Google Scholar Baher El Kaliouby Baher El Kaliouby 3Department of Geology, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt Search for other works by this author on: GSW Google Scholar Geology (1990) 18 (8): 761–764. https://doi.org/10.1130/0091-7613(1990)018<0761:GAIEFI>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Mohamed Sultan, Kevin R. Chamberlain, Samuel A. Bowring, Raymond E. Arvidson, Hassan Abuzied, Baher El Kaliouby; Geochronologic and isotopic evidence for involvement of pre-Pan-African crust in the Nubian shield, Egypt. Geology 1990;; 18 (8): 761–764. doi: https://doi.org/10.1130/0091-7613(1990)018<0761:GAIEFI>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 SocietyGeology Search Advanced Search Abstract Two Late Proterozoic granitic bodies from the Eastern Desert of Egypt, the ca. 578 Ma Nakhil and the ca. 595 Ma Aswan granites, provide insights into processes of crust formation in the Arabian-Nubian shield. Evidence for involvement of an older crustal component in the formation of the Nakhil granite includes (1) U/Pb zircon data that establish a crystallization age of 578 ±15 Ma and indicate the presence of inherited zircons possibly as old as 1.6 Ga; (2) an elevated model initial 87Sr/86Sr (0.7136); and (3) an elevated initial 207Pb/204Pb (15.561) relative to model mantle compositions at 578 Ma. Evidence for involvement of an older crustal component in the Aswan granite comes from the elevated initial 207Pb/204Pb (15.611). In contrast, extensive crustal contamination is not reflected in the high initial ϵNd(+5.7) for the Nakhil and the low initial 87Sr/86Sr (0.7029) for the Aswan granite. The contrasting inferences from the different isotopic systems can be explained by the high whole-rock Nd and Sr concentration for the Nakhil (87 ppm Nd) and the Aswan (173 ppm Sr) granites, respectively, that suggest that the Nd and Sr isotopic composition of the older component has been overshadowed by the more primitive material. Similar contrasts in Ph, Sr, and Nd isotopic data from the eastern and western shield margins can be interpreted in the same manner and might suggest widespread involvement of older crustal components in the formation of the Late Proterozoic Arabian-Nubian shield. 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.