赣江下游地区的风成沉积物

Aeolian Sediment in Down Stream Area of Ganjiang River, China

经C14 测年 ,认为赣江下游广泛分布的“莲塘组”和“湖口组”沙质沉积物 ,并不是分别形成于晚更新世早期和晚期 ,而是不早于 30kaBP ,一直沿用的关于“莲塘组”和“湖口组”的划分方案值得商榷。以新建县厚田地区为工作重点 ,通过对沉积物的沉积结构、形组分析、电镜扫描等室内分析和野外沉积构造调查 ,将“莲塘组”划分为上下两段 ,确认“莲塘组”上段和“湖口组”均为风成沉积 ,并指出风成沉积与河流沉积在沉积结构和构造方面的重大差异。

Liantang and Hukou formations widely distribute in down stream area of Ganjiang River. The different views have been existing about their formation times and environmental significance. Some researchers thought that they are alluvial sediments of Ganjiang River that formed in middle period of Pleistocene to beginning of later period of Pleistocene. Other researchers thought that they are aeolian sediment formed in later period of Pleistocene. By using {} 14C data, sedimentary texture, A-axis tendency of quartz sands, micro-morphologic pattern and sedimentary structure investigation, the author thinks that Liantang and Hukou formations formed after 30 ka BP. Liantang formation can be classified into two parts: the upper one and the lower one. The upper Liantang formation and Hukou formation are aeolian sediment, the lower Liantang formation is alluvial sediment of Ganjiang River. The great differences of sedimentary texture and structure between aeolian and alluvial sediment are pointed out.