Abstract:

The characteristics of sediments,such as their sequences,particle-size dis-tribution,constituents of minerals and detritus and the surface features ofquartz grains,are discussed here with respect to environments relative to the upper tributaries,braided channels of the upper-middle reach,meander-ing channels of the middle-lower reach and the deltaic distributary-monthbars within the system of Luan drainage,as well as to the coastal beach,the coastal dume and the beach of the Beidaihe cliffed coast.This study shows that sediments from individual environments mentioned above are different and,therefore,their features can be used for identifying environments of sedimentation.The diverse environments are characterized by apparent different cumulative probability curves.The constituents of minerals and detri-tus derived from the same source area are functions of transport distance andcurrent agent,especially when they are of unhomogeneous nature.The surfacefeatures of quartz grains are indicative of environments of sedimentation,e.g.of aeolian,marine and fluvial conditions.This study suggests that Luanriver is a middle-small,seasonal and sand-rich one of short source.There-fore,its sediments are abundant in sands with only a few of mud interca-lations.The sand grains is coarse and,in addition,there are gravels andmud gravels at the base of section,the content of minerals is less than thatof detritus,with maturity being lower.The dune is well deveoped on banksof the stream and this demonstrates that the wind may be strong enough during the dry season.The delta is resulted primarily from the agent ofstream,but certain tidal action may also be involved.The sediments on the beach near the Luan river mouth are distinct from that on the beach ofBeidaihe cliffed coast due to the distinction between them.