139736eo.pdf (20MB) - Japan Oceanographic Data Center

SEDIMENTARY STRUCTURE OF THE NORTHERN RED SEAPREPARATION OF Al: 1,000,000 BATHYMETRIC CHARTOFTHE/UORTHERNREDSEAANDSTUDYOFTHEMORPHOSTRUCTURAL FRAMEWORK BY CARTOGRAPHICANALYSISA. FERRAGNE, R. GRIBOULARD, R. PRUD'HOMME,J-M. RATEL AND M. VIGNEAUXInstitut de Geologie du Bassin dAquitaineUniversite de Bordeaux I35 1, Cours de la Liberation33405 Talence Cedex, FranceABSTRACTContinuous analysis of the northern Red Sea domain has been made for the marine and thecontinental areas. Al: 1,000,000-scale bathymetric chart has been drawn on the basis of relevantGEBCO plotting sheets, correlated with marine charts from the Service Hydrographique de laMarine. The morphology is described in the structural framework of this domain, with a threedimensionalvisualization of the seafloor relief. The orientation and deep variations of the axialvalley are shown, with the presence of submarine deeps. The main characteristics of the marginalshelf are indicated both in the morphology and the lithological and sedimentary structure. Theevident dissimilarities between the Gulfs of Suez and Aqaba, because of their genetic differences,are perfectly illustrated. Cartographic analysis, by a filter effect, allows the elaboration of asynthetic morphostructural sketch. The essential part of the ante-opening regional geologicalstructure (structure at 3WN, Zabargad transitional zone, at 20'N A1 Nadj fault zone) is revealed;this part controls the evolution of the marine domain. The role of rifting structures, such astransform faults, is confmed. The Aqaba Gulf Fault appears clearly as a sinistral zone. The maindeeps bordering the median axis of the rift are observed to cross transversal structures. Throughthe investigation of depth variability by morphostructural analysis, a domain with differentmorphostructural characteristics can be defined, particularly with regard to regional geologicalevolution.339