海洋地质前沿2025，Vol.41Issue(8)：55-70,16.DOI:10.16028/j.1009-2722.2024.239
强烈断陷期湖盆高精度层序特征及控制因素
High-precision sequence characteristics and controlling factors of lacustrine basin in rift-climax period:a case study in the Second Member of Liushagang Formation,Beibu Gulf Basin
摘要
Abstract
The accurate identification and subdivision of high-precision sequences play a fundamental role in es-tablishing an essential framework for analyzing the spatio-temporal evolution of depositional systems in continent-al rift basins in rift-climax period and for interpreting shifts in paleoclimate.We proposed a sequence stratigraph-ic framework focusing on the study of the Second Member of the Liushagang Formation(the L2 Member)in the Weizhou Exploration Area of the Beibu Gulf Basin.Using three-dimensional seismic data with well-log data,in-tegrating seismic stratigraphy,and well-log stratigraphy and cyclostratigraphic approaches,we extended study from the low frequency sequence to high frequency sequence to realize the identification and subdivision of high-precision sequences of lacustrine rift basin during rift-climax period,and calibrated against the astronomical timescale.Results show that the subdivision of the Second Member of the Liushagang Formation(L2 Member)in-to three third-order sequences(SQ1 to SQ3,bottom-top).Furthermore,astronomical cycle analysis revealed that the total deposition duration of the L2 Member was 12.15 Ma:3.24 Ma for SQ1,6.48 Ma for SQ2,and 2.43 Ma for SQ3.According to astronomical cycle characteristics,combined with wavelet transform analysis,8 fourth-or-der and 33 fifth-order sequences within SQ1,16 fourth-order and 66 fifth-order sequences within SQ2,and 6 fourth-order and 23 fifth-order sequences within SQ3,were recognized.The average duration of these sequences was approximately 0.405 Ma for fourth-order and 0.1 Ma for fifth-order sequences.The long orbital period sig-nals show different confidence and signal strength in multitaper method(MTM)and evolution spectrum analysis,respectively.Tectonic activity is assumed to be the predominant influence on the development of low-frequency sequences in rift basin.The SQ1 highstand systems tract was characterized by the development of sublacustrine fans,which approximately formed during the Early Eocene Climatic Optimum(EECO).It is hypothesized that the evolution of the set of sublacustrine fans was influenced by the EECO event.This study provided a theoretical basis for depicting characterization of deep-water sedimentary fills in lacustrine rift basins during rift-climax peri-od,and a valuable guidance for hydrocarbon exploration and resource assessment in the region.关键词
高精度层序/强烈断陷期/时频分析/天文旋回/北部湾盆地/流沙港组Key words
high-precision sequence/rift-climax/time-frequency analysis/astronomical cycle/Beibu Gulf Basin/Liushagang Formation分类
天文与地球科学引用本文复制引用
陈绵培,谈明轩,任培罡,张福榕,吴峰,张鹏辉,崔浩楠..强烈断陷期湖盆高精度层序特征及控制因素[J].海洋地质前沿,2025,41(8):55-70,16.基金项目
中央高校基本科研业务费项目"北部湾盆地北部坳陷古近纪'源-汇'特征及其对南海西北部古水系演化的指示作用"(B220202047) （B220202047）
