Study On Quaternary Strata In Yingjiang Valley Of Yunnan

Taking the quaternary strata in Yunnan Yingjiang valley as research object, thisthesis surveyed the quaternary strata and established the stratigraphic sequence inorder to explain the new tectonic movement in this study area.Relying on modern testing technology, field investigation, measurements ofterraces profile at all levels and analysis of the results of the samples, the study onthe quaternary strata of the study area is done adequately based on the theory ofgeomorphology, geochronology, stratigraphy and previous research. The thesis usessixteen profiles that one profile in Early Pleistocene strata; one profile in MiddlePleistocene strata; eleven profiles in Late Pleistocene strata and three profiles inHolocene.Quaternary strata were identified in each age stratum and the distribution ofDayingjiang valley: The seventh terrace belongs to Early Pleistocene strata, Thesixth terrace belongs to Middle Pleistocene strata, the second to fifth terrace belongsto Late Pleistocene strata and the fist terrace and floodplain belongs to Holocene.There are seven terraces in Lianghe basin utmost, the sixth and seventh terrace onlysporadically developed in the eastern part of the basin. From floodplain to theseventh terrace are on the left bank of Yingjiang river in Lianghe basin, but theterraces on the right bank of river are missing, like the third and the forth terraces.There are only four terraces developed in Yingjing basin, the fourth terracedeveloped at Mangguang area and the terrace on both side of the valley is missingand incomplete, the first terrace is missing on the right bank of Yingjiang river.The Quaternary strata of Dayingjiang from old to new by finishing profile are:Early Pleistocene strata: gravel layer; sand; gravel layer. Middle Pleistocene strata:gravel layer; sand, coarse sand interbedded with gravel layers; gravel layers. LatePleistocene strata: gravel layer; clayey silt layer; clay layer; sand layer; gravel layer.Holocene: gravel layer; sand layer; clayey silt layer; gravel layer.In sedimentary formation: Early Pleistocene deposition are mainly alluvialfacies and riverbed facies; Middle Pleistocene are primarily fluvial, alluvial and lacustrine deposition; Late Pleistocene are primarily riverbed and lacustrine faciesdeposition; Holocene deposition are primarily riverbed, alluvial and flood alluvialfacies.