广东北江流域第四系时代划分  

THE DIVISION OF THE QUATERNARY STRATA OF BEIJIANG BASIN IN GUANGDONG

作　　者：潘懋 郑春江 云祖铿 马铭留 莫鼎新 

机构地区：[1]北京大学 [2]中国环境监测总站 [3]华南环保所 [4]广西科学院

出　　处：《热带地理》1992年第3期202-209,共8页Tropical Geography

摘　　要：广东北江干流流域的第四系发育很差,且研究程度很低。本文通过详细的野外调查,结合少量必要的钻探资料,主要运用地貌对比(河流阶地对比与灰岩溶洞分析)、沉积物分析、'C与U—系等测年方法对区内的第四纪沉积物进行了详细的研究,提出了初步的划分方案:区内最老的沉积物形成于早更新世(或N_2～Q_1),在地貌上构成第三级阶地;第二级阶地的红土砾石层的形成时代早于马坝人动物群,不晚于中更新世早期(Q_2~1);本区上更新统不很发育,仅在清运盆地底部见有晚更新世晚期的砂砾层(Q_3~3);全新统发育且保存完整,在上游地区构成一级阶地,下游为宽广的冲积平原,自下而上可细分为三角组(7500～12 000a B.P.、横栏组(5000～7500 a B.P.、万顷沙组(2500～5000 a B.P.)和灯笼沙组(<2500aB.P.)。The Quaternary strata along the main reaches of the Beijiang River in Guangdong Province are poorly developed and less studied. The main characters can be summarized as being: (1) discontinuity in spatial distribution; (2) incompletion in time distribution; (3) small thickness; (4) lack of fossils. Through detailed field surveying, mainly by means of geomorphological correlation (terraces and caves), sediment analyses, ^(14)C and U-series timing, combined with drilling, a division scheme of the Quaternary strata in this region is put forward.1. The red-clayey conglomerates on the third terrace in Shaoguan Basin may have been formed in Early Pleistocene (Q_1) or earlier, while in Yingde Basin, the third terrace is underdeveloped, only developed the first and second tarraces, which can be correlated with their counterparts in Shaoguan Basin. The conglomerates on the second terrace were formed earlier than Maba Man fauna and later than Early Mid-Pleistocene (Q_2~1). The yellow clayey silts on the first terrace were formed in Early Holocene (later than 18000～19000 a B. P.).2. Qingyuan Basin is significantly different from Shaoguan and Yingde Basins. There is no stature of Lower or Middle Pleistocene, Only a thin cover of late Pleistocene fluvial sediments (Q_3~3) overlying on the weathering mantle of basic rocks. The Holocene strata of this basin developed well, whose thickness being 20～30 m, and geomorphologically being a wide fluvial plain. From bottom to top, the Holocene strata can be subdivided into four formations: Sanjiao Formation, Henglan Formation, Wanqinshan Formation and Denglongsha Formation. The time of each formation is respectively 7500～12000 a B.P., 5000～7000 a B. P., 2500～5000 a B. P. and 2500 a B. P.. The sands and gravels at the bottom of Sanjiao Formation may belong to Upper Pleistocene.

关 键 词：河流 沉积物 第四纪 溶洞 划分 

分 类 号：P512.2[天文地球—地质学]