摘要
更新世以来沉积环境演变对探讨珠江三角洲发育形成、古地理环境的变迁具有重要意义。在收集、整理9425个钻孔数据基础上,文章重新厘定了钻孔中更新统地层,利用ArcGIS和GoCAD重建了珠江三角洲更新统地层和基底断裂的三维结构。结果表明:地层沉积中心分布说明了更新统石排段和西南镇段地层分布、内部结构受到了NW、NE以及近EW向三组断裂的控制;更新世西江、北江和东江等主要古河谷的发育位置与珠江三角洲盆地基底较深的位置基本吻合,且沿着构造线发育形成平行岭谷地貌,但与现今河道位置不同。西南镇段沉积时沉积中心、分布范围以及厚度与石排段有所不同,反映了珠三角基底断块发生了不均匀沉降。
The evolution of sedimentary environment in the Pearl River Delta(PRD)since the Pleistocene is vital for the research on the plain development and changes of the paleogeography of the PRD.Based on 9425 boreholes collected,the redefinition of stratigraphic classification of each borehole is carried out.Also,3D structures of 12main basement faults and Pleistocene strata in the PRD are constructed with ArcGIS and GoCAD.The reconstructed model shows that the Late Pleistocene strata are unevenly distributed,among which the Shipai Group and Xinanzhen Group are dispersed in the PRD.The distribution of the deposit center of Pleistocene strata illustrates that the distribution and inner structure of Shipai Group and Xinanzhen Group are seriously impacted by three groups of main faults in north-east,east-west and north-west directions.The ancient channels including Xijiang River,Beijiang River,Dongjiang River and Tanjiang River,developed along major tectonic lines,forming the landform of parallel ridge-valley,but their positions were different from today's river.The top elevations of Shipai Group and Xinanzhen Group are between-15m and-50m,and between-5m and-45m respectively.The deepest burial depth of the two strata is located around Cuiheng New District,which is deduced as the outlet to the sea of the ancient channels.According to the dating data in Chencun area in Foshan,and the elevation difference of 30m in the Xinanzhen Group near to Rongqi Town,it is inferred that the Enping-Xinfeng Fault occurred during or after the deposition of the Xinanzhen Group.The absence of Shipai Group around Modaomen area indicates that the Xijiang valley developed after Shipai Group deposition,which indirectly proves that the uneven settlement of each fault block in the PRD occurred before the deposition of Sanjiao Group.
作者
李炎华
侯卫生
陈秀文
张献河
林小明
李宏卫
LI Yanhua;HOU Weisheng;CHEN Xiuwen;ZHANG Xianhe;LIN Xiaoming;LI Hongwei(School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai 519082,Guangdong;Guangdong Provincial Key Laboratory of Geodynamics and Geohazards,Guangzhou 510275,Guangdong;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,Guangdong;Guangdong Geological Survey Institute,Guangzhou 510080,Guangdong)
出处
《第四纪研究》
CAS
CSCD
北大核心
2022年第3期869-879,共11页
Quaternary Sciences
基金
国家自然科学基金项目(批准号:41970302和41772345)
广东省国土资源保护与治理专项资金(地质灾害防治方向)省级项目"珠江三角洲基底断裂探查研究项目"(批准号:2017201)共同资助。
关键词
珠江三角洲
更新统
三维结构重建
沉积中心
古河道
Pearl River Delta
Pleistocene
3D structure reconstruction
deposit center
palaeo-valley
