下刚果盆地A区块下白垩统阿尔布阶混积相研究
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摘要
下刚果盆地A区块下白垩统阿尔布阶为一套碳酸盐物质混杂陆源砂、泥沉积,具有典型的混合沉积特征。依据研究区地质背景、测井地质、地震资料和岩石薄片鉴定等资料,对阿尔布阶混合沉积作用进行了精细分析。研究结果如下:①研究区混合沉积特征在剖面结构上表现为由陆源碎屑与碳酸盐物质交互沉积、陆源碎屑与混积物交互沉积、碳酸盐物质与混积物交互沉积和混积物本身的交互沉积等4种类型;②提出了适合该区的"间断-交叉"型碳酸盐物质夹陆源碎屑混积机理,并建立了该区的混积模式;③随着该时期海水的进入、海侵的扩大,整体上阿尔布阶依次经历了混积缓坡、混积局限台地、混积开阔台地和混积陆棚的演化,发育了灰泥丘、砂质浅滩、鲕粒滩、生屑滩、藻屑滩、潮下静水泥、风暴流等众多微相。
Lower Cretaceous Albian in block A of Lower Congo Basin deposited a set of carbonate mixed facies composed of terrigenous sand and mud.Based on regional geologic setting,logging geology,seismic data and thin section observation,the mixed deposition of Albian in the study area is analyzed.The research result shows that: ①The profile structure is characterized by 4 types,including alternating deposits of terrigenous debris and carbonate,alternating deposits of terrigenous debris and diamicton,alternating deposits of carbonate and diamicton,and alternating deposits of diamicton themselves;②A mixed deposition mechanism appropriate for the study area is proposed,called "discon-tinuity-overlapping" mixed deposition,and the mixed deposition model is established;③With the seawater entering and the expansion of transgression,the Albian experienced mixed gentle slope,mixed restricted platform,mixed open platform and mixed continental shelf successively,and developed numerous sedimentary microfacies such as lime mud mound,sandy shoal,oolitic beach,bioclastic shoal,algal-clastic beach,subtidal static water mudstone and tempestite.
Lower Cretaceous Albian in block A of Lower Congo Basin deposited a set of carbonate mixed facies composed of terrigenous sand and mud.Based on regional geologic setting,logging geology,seismic data and thin section observation,the mixed deposition of Albian in the study area is analyzed.The research result shows that: ①The profile structure is characterized by 4 types,including alternating deposits of terrigenous debris and carbonate,alternating deposits of terrigenous debris and diamicton,alternating deposits of carbonate and diamicton,and alternating deposits of diamicton themselves;②A mixed deposition mechanism appropriate for the study area is proposed,called "discon-tinuity-overlapping" mixed deposition,and the mixed deposition model is established;③With the seawater entering and the expansion of transgression,the Albian experienced mixed gentle slope,mixed restricted platform,mixed open platform and mixed continental shelf successively,and developed numerous sedimentary microfacies such as lime mud mound,sandy shoal,oolitic beach,bioclastic shoal,algal-clastic beach,subtidal static water mudstone and tempestite.
引文
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[9]刘祚冬,李江海.西非被动大陆边缘含油气盐盆地构造背景及油气地质特征分析[J].海相油气地质,2009,14(3):46-52.
[10]董桂玉,陈洪德,何幼斌,等.陆源碎屑与碳酸盐混合沉积研究中的几点思考[J].地球科学进展,22(9):931-939.
[11]江茂生,沙庆安.碳酸盐与陆源碎屑混合沉积体系研究进展[J].地球科学进展,1995,10(6):551-554.
[12]Yose L A,Heller P L.Sea-level control of mixed-carbonate-silici-clastic,gravity-flow deposition:Lower part of the Keeler Canyon Formation(Pennsylvanian),southeastern California[J].GSA Bulletin,1989,101(3):427-439.
[13]Markello J R,Read J F.Carbonate ramp-to-deeper shale shelf transitions of an Upper Cambrian intrashelf basin,Nolichucky Formation,Southwest Virginia Appalachians[J].Sedimentology,1981,28(4):573-597.
[2]Huber M,Sloan L C.Climatic responses to tropical sea surface tem-perature changes on a“greenhouse”Earth[J].Paleoceanogaphy,2000,15(4):443-450.
[3]沙庆安.混合沉积和混积岩的讨论[J].古地理学报,2001,3(3):63-66.
[4]郑荣才,周刚,董霞,等.龙门山甘溪组谢家湾段混积相和混积层序地层学特征[J].沉积学报,2010,28(1):33-39.
[5]董桂玉,陈洪德,李君文,等.环渤海湾盆地寒武系混合沉积研究[J].地质学报,2009,83(6):800-809.
[6]张锦泉,叶红专.论碳酸盐与陆源碎屑的混合沉积[J].成都地质学院学报,1989,16(2):87-92.
[7]白云程,周晓惠,万群,等.世界深水油气勘探现状及面临的挑战[J].特种油气藏,2008,15(2):7-10.
[8]张波.非洲加蓬×区块油气成藏条件及勘探潜力分析[J].海相油气地质,2006,11(1):30-34.
[9]刘祚冬,李江海.西非被动大陆边缘含油气盐盆地构造背景及油气地质特征分析[J].海相油气地质,2009,14(3):46-52.
[10]董桂玉,陈洪德,何幼斌,等.陆源碎屑与碳酸盐混合沉积研究中的几点思考[J].地球科学进展,22(9):931-939.
[11]江茂生,沙庆安.碳酸盐与陆源碎屑混合沉积体系研究进展[J].地球科学进展,1995,10(6):551-554.
[12]Yose L A,Heller P L.Sea-level control of mixed-carbonate-silici-clastic,gravity-flow deposition:Lower part of the Keeler Canyon Formation(Pennsylvanian),southeastern California[J].GSA Bulletin,1989,101(3):427-439.
[13]Markello J R,Read J F.Carbonate ramp-to-deeper shale shelf transitions of an Upper Cambrian intrashelf basin,Nolichucky Formation,Southwest Virginia Appalachians[J].Sedimentology,1981,28(4):573-597.
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