Based on drilling and seismic data, the Paleogene developed in Liaodong Bay can be divided into five third-order sequences bounded by six sequence boundaries. Through analyzing depositional systems in each sequence in...Based on drilling and seismic data, the Paleogene developed in Liaodong Bay can be divided into five third-order sequences bounded by six sequence boundaries. Through analyzing depositional systems in each sequence in detail, the Es-3 time was defined as fast rifting. During the deposition of the Es-3 member, the lake basin was continuous along the N-S direction but compartmentalized along the E-W direction by several N-S trending faults. Deposition was dominated by steep slope fans and fan deltas. The time of Es-2 and Es-1 was stable settling. The lake basin expanded substantially. The fan delta system and braided fluvial system were developed. Carbonate and clastic deposits were formed on the Liaoxi （west Liaohe） Rise. The time of Ed-3 time was again fast rifting. During this time, shale was deposited. In the time of Es-2, tectonic movement weakened. The basin was higher in the west and north, and lower in the east and south. A series of delta depositional systems were developed and smallscale slumping turbidite fans were present in semi-deep lake to deep lake. In the time of Ed-1, tectonic movement stopped. Flood plain deposition occurred. Finally the paper presents the characteristics of evolution and distribution of depositional systems both vertically and horizontally.展开更多
With a comprehensive geological and geophysical data base,the Paleogene in the Liaodong Bay area,which consists of the Kongdian,Shahejie and Donghying Formations from the base to top,was divided into 4 second-order se...With a comprehensive geological and geophysical data base,the Paleogene in the Liaodong Bay area,which consists of the Kongdian,Shahejie and Donghying Formations from the base to top,was divided into 4 second-order sequences and 8 third-order sequences based on the characteristics of the se-quence boundaries. Each third-order sequence is subdivided into the lowstand,lake transgressive and highstand systems tracts. The Lowstand systems tract (LST) is mainly composed of progradational parasequence sets,while the lake transgressive systems tract (TST) largely consists of the retrograda-tional parasequence sets and the highstand systems tract (HST) is dominated by the progradational parasequence sets. The main types of depositional systems include the shallow lake,semi-deep lake,deep lake,delta,fan delta,braided fluvial delta and nearshore subaqueous fan. The braided fluvial delta and fan delta depositional systems are mainly confined to the sequences of the lower SEs4-Ek,SEs3 and SEs1+2,while the sequences of SEd3,SEd2 and SEd1 are dominated by the delta and nearshore subaqueous fan depositional systems with the latter being developed at the downthrown side of the basin-bounding fault in each sequence. The evolution of the depositional systems is always con-trolled by the paleo-tectonic setting and the ancient landform in the space and geological time. It is concluded that the most favorable reservoirs are distributed in the Liaoxi low uplift and the central Liaozhong sag.展开更多
文摘Based on drilling and seismic data, the Paleogene developed in Liaodong Bay can be divided into five third-order sequences bounded by six sequence boundaries. Through analyzing depositional systems in each sequence in detail, the Es-3 time was defined as fast rifting. During the deposition of the Es-3 member, the lake basin was continuous along the N-S direction but compartmentalized along the E-W direction by several N-S trending faults. Deposition was dominated by steep slope fans and fan deltas. The time of Es-2 and Es-1 was stable settling. The lake basin expanded substantially. The fan delta system and braided fluvial system were developed. Carbonate and clastic deposits were formed on the Liaoxi （west Liaohe） Rise. The time of Ed-3 time was again fast rifting. During this time, shale was deposited. In the time of Es-2, tectonic movement weakened. The basin was higher in the west and north, and lower in the east and south. A series of delta depositional systems were developed and smallscale slumping turbidite fans were present in semi-deep lake to deep lake. In the time of Ed-1, tectonic movement stopped. Flood plain deposition occurred. Finally the paper presents the characteristics of evolution and distribution of depositional systems both vertically and horizontally.
基金Supported by Key Technologies Research and Development Program (Grant No.2001BA605A09-1)
文摘With a comprehensive geological and geophysical data base,the Paleogene in the Liaodong Bay area,which consists of the Kongdian,Shahejie and Donghying Formations from the base to top,was divided into 4 second-order sequences and 8 third-order sequences based on the characteristics of the se-quence boundaries. Each third-order sequence is subdivided into the lowstand,lake transgressive and highstand systems tracts. The Lowstand systems tract (LST) is mainly composed of progradational parasequence sets,while the lake transgressive systems tract (TST) largely consists of the retrograda-tional parasequence sets and the highstand systems tract (HST) is dominated by the progradational parasequence sets. The main types of depositional systems include the shallow lake,semi-deep lake,deep lake,delta,fan delta,braided fluvial delta and nearshore subaqueous fan. The braided fluvial delta and fan delta depositional systems are mainly confined to the sequences of the lower SEs4-Ek,SEs3 and SEs1+2,while the sequences of SEd3,SEd2 and SEd1 are dominated by the delta and nearshore subaqueous fan depositional systems with the latter being developed at the downthrown side of the basin-bounding fault in each sequence. The evolution of the depositional systems is always con-trolled by the paleo-tectonic setting and the ancient landform in the space and geological time. It is concluded that the most favorable reservoirs are distributed in the Liaoxi low uplift and the central Liaozhong sag.
