内波、内潮汐沉积和复合流沉积是二十余年来在古代深水环境中新发现的一种具牵引流性质的沉积相类型,由于地层沉积记录十分有限,制约了深水底流沉积的沉积学研究。大比例尺实测地质剖面和精细露头测量表明,底流沉积发育于凭祥盆地深水沉积之中,通过对其沉积构造精细剖析和古水流测量,识别出内波、内潮汐沉积和复合流沉积,其中内波、内潮汐沉积以双向交错层理、单向交错层理、透镜状层理为特征,复合流沉积以复合流层理、丘状交错层理和较陡的爬升波纹层理为特征,进一步表明存在浊流和底流的交互作用,为古代地层中的深水底流沉积提供了又一研究实例。
The internal-wave,internal-tide and combined-flow deposit of the ancient deep-water system is a new find in recent twenty years. As the sedimentary records are rare,the sedimentology research on the bottom currents in the deep-water system is restricted. Based on detailed analysis of the geological sections and sedimentary outcrop columns,there exists bottom current deposits in the deep-water deposits of Pingxiang Basin. This paper deeply analyzes the sedimentary structure and paleocurrent of these bottom current deposits. The bottom current deposits consist of internal-wave,internal-tide and combined-flow deposits. The internal-wave and internal-tide deposits are characterized by bidirectional cross lamination,unidirectional cross lamination and lenticular lamination. The combined-flow deposit is characterized by combined-flow ripple lamination,hummocky cross lamination and sharp climbing ripple lamination. Furthermore,it shows the interaction between turbidity and bottom currents. This paper provides a new sample for the research of bottom currents in the ancient deep-water system.