Tectonic Evolution in the Southern Red Sea and Its Possible Significance to Older Rifted Continental Margins

Abstract

Research Article| October 01, 1972 Tectonic Evolution in the Southern Red Sea and Its Possible Significance to Older Rifted Continental Margins R. W HUTCHINSON; R. W HUTCHINSON Department of Geology, University of Western Ontario, London, Ontario, Canada Search for other works by this author on: GSW Google Scholar G. G ENGELS G. G ENGELS Mobil Producing Nigeria, PMB 12054, Lagos, Nigeria Search for other works by this author on: GSW Google Scholar Author and Article Information R. W HUTCHINSON Department of Geology, University of Western Ontario, London, Ontario, Canada G. G ENGELS Mobil Producing Nigeria, PMB 12054, Lagos, Nigeria Publisher: Geological Society of America Received: 01 Jul 1971 Revision Received: 03 Apr 1972 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1972, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1972) 83 (10): 2989–3002. https://doi.org/10.1130/0016-7606(1972)83[2989:TEITSR]2.0.CO;2 Article history Received: 01 Jul 1971 Revision Received: 03 Apr 1972 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation R. W HUTCHINSON, G. G ENGELS; Tectonic Evolution in the Southern Red Sea and Its Possible Significance to Older Rifted Continental Margins. GSA Bulletin 1972;; 83 (10): 2989–3002. doi: https://doi.org/10.1130/0016-7606(1972)83[2989:TEITSR]2.0.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 The northern end of the Danakil horst block in Eritrea has undergone major asymmetric subsidence but only minor separation along the Ethiopian rift, the block being covered by a veneer of Pleistocene evaporites. The supporting evidence includes stratigraphic relations in pre-rifting Jurassic formations, lithofacies variations in the Pleistocene evaporites, and structural information. Recent studies of basalt age-space relations and petrochemistry in the Afar region are also in accord with this view. Additional studies will be required to determine o t what degree this condition persists southward in form of a subsided sialic crustal block beneath the basalt-floored Afar depression, or conversely to what degree there has here been separation of the Danakil horst from the Ethiopian plateau due to rotation, with asymmetric tilting, of the horst block. Although the data are less compelling than in the case of the Danakil horst, recent offshore geophysical surveys and drilling in the southern Red Sea suggest the possibility of there being a second, older, more deeply subsided sialic block covered by a thick Miocene evaporite and volcanic sequence beneath the shallow margins of the Red Sea itself.If correct, this interpretation would require only minor separation by drift of the Arabian and Nubian plates across the Ethiopian and Red Sea rifts. It would, instead, involve major subsidence, with extensive evaporite deposition and basaltic volcanism covering the subsiding blocks, as the explanation for the large apparent separation.Although the presence of subsided sialic blocks beneath the Red Sea and southern Afar is interpretive and requires further substantiation, the existence of such a block beneath the north end of the Danakil horst is probable. It is therefore suggested that subsidence may be an important tectonic development along the margins of newly rifted continental plates. Fault-block tectonics in the style suggested for the Danakil-Afar area, characterized by asymmetrically subsiding sialic blocks, may offer an explanation for many features common to some continental margins. These include shallow continental shelves with incised submarine canyons and deep but local offshore evaporite basins. 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.