三水盆地SB01孔的有机质类型及其古气候指示意义

 采用有机岩石学和全岩热解分析方法，对三水盆地SB 01孔的有机质类型进行了研究。根据有机质类型及分布特征，结合岩性变化和已有的其它古气候证据，分析了岩芯沉积时期的古气候演变过程。有机岩石学分析显示，SB 01孔岩芯沉积物中的有机质类型以II型（包括II1和II2型）为主，少量为I型，偶见III型。热解分析结果表明有机质的热演化程度较低，有机碳在热演化过程中损失不大。I、II1和II2型有机质类型分别指示干旱、干燥和温湿的气候条件。莘庄组艮坑段顶部以II1型有机质类型为主，表明其沉积时期盛行较为干燥的气候条件。〖XCchen1.TIF;%89%89〗心组红岗段亚段A的有机质主要为II2型，夹有含I和II1型的层位，反映温湿气候条件占主导地位。亚段B的有机质类型为II2与II1（或I型）交替出现，反映温湿与干燥（或干旱）气候条件的快速波动变化。亚段C下部主要为II1和I型有机质，中上部以II2型有机质类型为主，指示其气候由前期的干燥（或干旱）条件转为以温湿条件为主。

Organic Matter Types of Core SB-01 in the Sanshui Basin and Their Paleoclimate Implications

Organic matter types of core SB 01 from the Sanshui Basin were analyzed using organic petrology method and Rock Eval pyrolysis. Based on organic petrology results, the organic matter is dominated by type II (including type II1 and type II2), mostly type II1. Type I organic matter intermittently occurs at some intervals while Type III organic matter is occasional in presence. Pyrolysis results show that the organic matter is of lower thermal maturity and the organic carbon loss could be ignored, as indicated by the lower Tmax values. Organic matter of Types I, II1 and II2 was deposited under arid, drier and humid climate conditions, respectively. The uppermost part of the Xinzhuang Formation is characterized by Type II1, related to a dry climatic condition. Sub member A of the Honggang Member is dominated by organic Type II2, sandwiched by Type I and II1, suggesting a prevailing humid climatic condition. Sub member B is characterized by alternations of organic Types II2 and II1/I, reflecting rapid fluctuations of humid and dry/arid climatic conditions. Sub member C shows Type II1 and I in the lower part and shifts to Type II2 in the middle and upper parts, indicating a dry/arid climate condition followed by a prevailing humid climatic condition.