Grain Size Distribution And Its Environmental Signiifcance Of Nanton Since The Quaternary

Taking advantage of related theory of sedimentary geology, according togranularity analysis method, this research makes a comprehensive analysis to thecurve and parameter characteristics such as probability cumulative curvecharacteristic, frequency cumulative curve characteristic,etc..,divides stratum moreprecisely and analyses sedimentary environment as well as its evolution.Through comprehensive anslysis of sediment particle size,pollen analysis,datingdate, wave velocity testing etc…this paper comprehensively analyzes controlledovarian sedmentary characteristic and his evolution, at the same time, absorbingprevious achievements, to make a comprehensive anslysis to the evolution ofsedimentary environment since quaternary of Nantong.According to detailed description to controlled standard orifice of Nantong,combing with existed achievements, this paper suggests strata from beloe to aboveincludes Pleistocene lower Haimen fm, middle Pleistocene Qidong fm, upperPleistocene Kunshan fm, upper Pleistocene gehu fm and Holocene Rudong fm.According to the research of frequency curve of standard orifice, it is not socomplicated to the frequency of standard orifice particle size. Subjects whtch particlesize diameter range from0.3μm-1000μm, most of them are more likely Masadadistribution, and negative skew occupy the majority of eccentric state, subject has astrong hydrodynamic condition. Cumulative relative frequency curve mainlydisplayed as two-section pattern,.According to analysis of parameters of controlled drilling particle diameter,granule group mainly include coarse sand and powder fine sand when modal numbersdistribute range from2.7-7.7Ф as well as it is mainly medium coarse sand whenmodal numbers distribute range from4-7.7Ф,especial0.3-8Ф, and the clay, sortingfeature is satisfying.Skewness is mainly negative,extremely negative,and thenproximal symmetric. It indicates a satisfying feature of sediments and can be mainlydivided as coarse and power.Controlled drilling is more comprehensive and detailed analysis, combined withsome former studies on the region, come to the depositional environment of NantongCity, bottom-up eight cycles, sedimentary hydrodynamic experienced in energy-lowenergy-changes in the low energy-high energy-high energy-low energy-lowenergy-low-energy depositional environment and alluvial-based alluvial. The sporopollen assemblage in controlled standard Nantong hole could bedivided into five sporopollen zone such as Ⅰ. Ⅱ. Ⅲ. Ⅳ. Ⅴ,eleven sporopollensub-zones. According to the Pollen assemblage, lithologic characteristics, combinedwith TL dating data that the pollen assemblage zone with V reflects for the Holoceneof the deposition, IV zone reflects the Late Pleistocene of deposition, III zone reflectsthe deposition of the Middle Pleistocene,II zone reflects the deposition of thePleistocene, I zone reflects the deposition of the late Pliocene.