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The relationship between spore-pollen color and the degree of maturation of organicmatter is discussed with regard to oil generation and evolution,as typified by the Creta-ceous system in the Daqing Oil Field,central Songliao Basin,Northeast China.Color varia-tion of spores and pollen is considered as a function of sedimentary environment and ther-mal alteration.Sporo-pollen color is classified into seven grades,and the degree of thermalalteration is studied in terms of color index.Results show that the spore-pollen color in-dex for the strata at the depth of 1,000—3,000 m(stratigraphically from the first memberof the Liangjiang Formation to the upper Quantou Formation)ranges from 2.5—5.0,cor-responding to a palaeotemperature range of 60°—140℃.These are the optimum oil-gene-rating strata.The strata underlying the lower Quantou Formation below 3,000 m with thecolor index in excess of 5 and the palaeotemperature over 140℃ may be favorable for gasaccumulation.As for the strata at the depth of less than 1,000 m,i.e.,stratigraphicallyoverlying the second member of the Liangjiang Formation,which are characterized by acolor index of 1.0—1.5 and a palaeotemperature of less than 60℃,the degree of matura-tion of organic matter is lower than that in the oil-generating strata.
The relationship between spore-pollen color and the degree of maturation of organicmatter is discussed with regard to oil generation and evolution, as typified by the Creta-ceous system in the Daqing Oil Field, central Songliao Basin, Northeast China. Color varia-tion of spores and pollen is considered as a function of sedimentary environment and ther-mal alteration. Sporo-pollen color is classified into seven grades, and the degree of thermalalteration is studied in terms of color index. Results show that the spore-pollen color in- dex for the strata at the depth of 1,000-3,000 m (stratigraphically from the first member of the Liangjiang Formation to the upper Quantou Formation) ranges from 2.5-5.0, cor-responding to a palaeotemperature range of 60-140 ° C. These are the optimum oil-gene-rating strata.The strata underlying the lower Quantou Formation below 3,000 m with thecolor index in excess of 5 and the palaeotemperature over 140 ° C may be favorable for gasaccumulation. As for the strata at the depth of less than 1,000 m, ie, stratigraphically overlying the second member of the Liangjiang Formation, which are characterized by acolor index of 1.0-1.5 and a palaeotemperature of less than 60 ° C., the degree of matura-tion of organic matter is lower than that in the oil-generating strata.