Preliminary Study On Deposition Facies Of Xinghua Core At Northern Jiangsu Basin

The Northern Jiangsu Basin, predominated under the influence of East Asian Monsoon, is a key area that might provide environmental information to connects the marine records with the terreatrial records of China. The continuous sedimentary sequences in the basin contains abundant information of palaeoenvironments. Based on the analysis of lothological description, granularity characteristic, quartz surface texture characteristic and nature gamma curve, we established the deposition sequence of Xinghua Core above 150m.According to the lothological description, the granularity characteristic, the nature gamma curve, we have established the above 150m deposition sequence of Xinghua Core, dividing the deposition sections as follows: 150m~102.8m, deposit of fluvial-lacustrine alternative facies; 102.8m~48.78m, deposit of lacustrine facies; 48.78m~38.21m, deposit of swamp facies; 38.21m~11.62m, deposit of lacustrine facies; 11.62m~0m, deposit of lacustrine-swamp facies.We observed and t counted the quartz surface texture characteristic with SEM, the quartz surface texture combination is different in different deposition environment. In the fluvial deposit environment, the quartz superficial characteristic is primarily by the inferior circle, the conchoidal breakage fracture and the submarine hit pit, revealing the transformation of current to the quartz; In lake-deposit environment, quartz sand superficial characteristic is by primarily abraded edges and parallel cleavage, the quartz maintained the primitive characteristic, indicating the quartz received few transformation of fluent, different quartz grain has their different curve character.Withdrawed the nature gamma data according to the sedimentary facies, and combined deposition sequence, Through the Matlab we withdrawed quantification target of nature gamma curve shape characteristic such as the nature gamma curve average median, the relative center of gravity and difference variance root in each kind of deposition section, then we used logit discriminant analysis, established the distinction model of the entire 350m drill hole section and examined it, proved automatic distinguishing certain sedimentary facies by gamma curve was feasible.