The Middle Devonian ostracods from the Jiwozhai patch reef in Dushan, Guizhou Province, South China were described for the first time in this study. Twenty-nine species belonging to 20 genera were identified and figur...The Middle Devonian ostracods from the Jiwozhai patch reef in Dushan, Guizhou Province, South China were described for the first time in this study. Twenty-nine species belonging to 20 genera were identified and figured, including a new species named Wangshangkia jiwozhaiensis sp. nov. The ostracod fauna in the Jiwozhai patch reef represents a Givetian age. The ostracod assemblage belongs to the smooth-podocopid association, which is also ecologically equivalent to the Eifelian Mega-Assemblage Ⅲ. This association is indicative of shallow open-marine environments. The Jiwozhai patch reef fauna is primarily comprised of suspension feeders, including filter-feeding ostracods, corals, brachiopods and bryozoans. Ostracods from the Jiwozhai patch reef were compared to the ostracod faunas from Laurentia-Baltica at generic level, which reveals limited faunal exchanges between South China and Laurentia-Baltica during the Middle Devonian.展开更多
Numerous moundy reflections were found at the Upper Meishan Formation in southern Qiongdongnan Basin, South China Sea which are suspected reefs. However, no common understanding on the seismic and geologic interpretat...Numerous moundy reflections were found at the Upper Meishan Formation in southern Qiongdongnan Basin, South China Sea which are suspected reefs. However, no common understanding on the seismic and geologic interpretation was acquired. Based on seismic reflection identification, geometrical configuration description, wave impedance inversion, forward simulation, analysis of reef-building sedimentary environments and pseudomorph identification, these suspected-reef moundy reflections were studied in details.Three types of reefs were recognized, i.e., patch reef, platform-edge reef, and pinnacle reef. They have some typical characteristics of reefs, including moundy or lenticular shape, clear outline with crest and canal, internal foreset bedding, bidirectional uplap between limbs, and strong reflection at top and bottom. The patch reefs are of moundy seismic facies, with moderateestrong amplitude and moderate frequency, and distribute at the higher part of southern slope belt. Fore-reef and back-reef of patch reefs are slightly asymmetrical being perpendicular to palaeo-bathymetric orientation; while symmetrical to slightly asymmetrical being parallel to the palaeo-bathymetric orientation, and the wave impedance value is about 7 kg/m^3×m/s.Platform-edge reefs are of flat-moundy seismic facies with strong amplitude and moderate frequency, which develop at the carbonate platform edge of higher part of southern slope belt, and the wave impedance value is about 7.5 kg/m^3×m/s. Pinnacle reefs grow up on volcanic cones, forming the complex of pinnacle reef and volcanic cone. The Miocene Meishan Formation reefs in southern Qiongdongnan Basin, northern South China Sea, with high quality sourceereservoireseal assemblages, have good petroleum exploration prospects.展开更多
基金financially supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2023324)the Hubei Key Laboratory of Paleontology and Geological Environment Evolution,Wuhan Center of China Geological Survey(PEL-202301)+1 种基金the Science and Technology Fundamental Resources Investigation Program(Grand No.2023FY100900)the Natural Science Foundation of China(Grant No.41802018).
文摘The Middle Devonian ostracods from the Jiwozhai patch reef in Dushan, Guizhou Province, South China were described for the first time in this study. Twenty-nine species belonging to 20 genera were identified and figured, including a new species named Wangshangkia jiwozhaiensis sp. nov. The ostracod fauna in the Jiwozhai patch reef represents a Givetian age. The ostracod assemblage belongs to the smooth-podocopid association, which is also ecologically equivalent to the Eifelian Mega-Assemblage Ⅲ. This association is indicative of shallow open-marine environments. The Jiwozhai patch reef fauna is primarily comprised of suspension feeders, including filter-feeding ostracods, corals, brachiopods and bryozoans. Ostracods from the Jiwozhai patch reef were compared to the ostracod faunas from Laurentia-Baltica at generic level, which reveals limited faunal exchanges between South China and Laurentia-Baltica during the Middle Devonian.
基金National Science and Technology Major Project of China (No. 2016ZX05026-007)National Natural Science Foundation of China (No. 41502081)
文摘Numerous moundy reflections were found at the Upper Meishan Formation in southern Qiongdongnan Basin, South China Sea which are suspected reefs. However, no common understanding on the seismic and geologic interpretation was acquired. Based on seismic reflection identification, geometrical configuration description, wave impedance inversion, forward simulation, analysis of reef-building sedimentary environments and pseudomorph identification, these suspected-reef moundy reflections were studied in details.Three types of reefs were recognized, i.e., patch reef, platform-edge reef, and pinnacle reef. They have some typical characteristics of reefs, including moundy or lenticular shape, clear outline with crest and canal, internal foreset bedding, bidirectional uplap between limbs, and strong reflection at top and bottom. The patch reefs are of moundy seismic facies, with moderateestrong amplitude and moderate frequency, and distribute at the higher part of southern slope belt. Fore-reef and back-reef of patch reefs are slightly asymmetrical being perpendicular to palaeo-bathymetric orientation; while symmetrical to slightly asymmetrical being parallel to the palaeo-bathymetric orientation, and the wave impedance value is about 7 kg/m^3×m/s.Platform-edge reefs are of flat-moundy seismic facies with strong amplitude and moderate frequency, which develop at the carbonate platform edge of higher part of southern slope belt, and the wave impedance value is about 7.5 kg/m^3×m/s. Pinnacle reefs grow up on volcanic cones, forming the complex of pinnacle reef and volcanic cone. The Miocene Meishan Formation reefs in southern Qiongdongnan Basin, northern South China Sea, with high quality sourceereservoireseal assemblages, have good petroleum exploration prospects.
