levell-南阿曼-碰撞.pdfVIP

GeoArabia, Vol. 7, No. 4, 2002 Gulf PetroLink, Bahrain 721 A possible Albian impact crater at Murshid, southern Oman Bruce Levell 1 , Pascal Richard 2 and Folco Hoogendijk 2 , Petroleum Development Oman ABSTRACT During interpretation of a 3-D seismic survey in southern Oman a solitary, 2.5-km-wide circular basin with a central peak and raised rim was identified in the subsurface 35 km west of the Marmul oil field. The feature is the only one of its kind in the area. The basinal structure is probably of Late Cretaceous (Albian) age and the regional geology strongly suggests that it is neither a volcanic crater nor related to salt-dome tectonics or salt dissolution. It possibly represents a crater formed by a terrestrial impact event and has been named the Murshid crater. This report does not constitute a detailed investigation of the possible impact crater but rather records the 3-D seismic observations and the drilling that has taken place near the structure so far. INTRODUCTION During interpretation of a newly acquired 3-D seismic survey for oil exploration in southern Oman, a solitary 2.5-km-diameter circular basinal feature was identified as a possible impact structure and was named the Murshid crater. It lies 35 km west of the Marmul oil field in the South Oman Salt Basin (Figure 1). The center of the structure is at latitude 18o10’59N, longitude 54o55’08”E, and it is buried at a depth of approximately 380 m below mean sea level (680 m below the ground surface). The authors are petroleum geologists who felt that the Murshid basinal structure needed reporting to the wider scientific community. It is their hope that, by doing so, geoscientists with more knowledge of impact structures will be stimulated to study the structure in the detail it deserves. Seismic Data The structure is in an area covered by a 3-D seismic survey acquired in 1996. The survey provided good-quality data down to the base of the Cretaceous. Imaging problems due to multiple reflecti