Coal petrography variation in the sequence stratigraphic frame of the Jurassic coal measures of Dameigou mine area in Northern Qaidam Basin
Coal petrography variation in the sequence stratigraphic frame of the Jurassic coal measures of Dameigou mine area in Northern Qaidam Basin
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发表时间：
2009
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通讯作者：
Gao Di
中科院分区：
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作者：
Gao Di
为了揭示内陆盆地沼泽基准面与煤岩变化的关系，运用层序地层学原理，对柴达木盆地北部大梅沟矿区侏罗系煤系层序地层格架中的煤岩变化进行了研究。共识别出9个层序界面(包括区域不整合面、切割谷地、区域构造应力转换界面和地层不连续面色)，将侏罗系煤系划分为3个二级层序和8个三级层序。研究区主要煤(煤F)形成于废弃辫状河平原高位沼泽环境。煤显微组分具有高惰性组(平均59.1%)和低镜质组(平均23.9%)的特征。根据煤显微组分在垂向剖面上的变化，将F煤划分为1个四级层序和5个五级层序；在垂向剖面上，F煤镜质组含量总体呈上升趋势，反映了三级层序SIII6湖侵体系域基准面逐渐抬升的动力背景。
In order to reveal the relationship between the base level in the bog of inland basin and the coal petrography variation,principle of the sequence stratigraphy has been used to study the coal petrography variation in the sequence stratigraphic frame of the Jurassic coal measures of Dameigou mine area in Northern Qaidam Basin.A total of 9 sequence boundaries have been identified(including regional unconformity surface,incised valley,regional tectonic stress transforming interface and color of strata discontinuous surface),which divided Jurrasic coal measures into 3 second-order sequences and 8 third-order sequences.The major coals(coal F) in the research area were formed in the environment of highstand swamp in the abandoned braided river plain,the coal macerals are characterized by high inertinite(average 59.1 %) and low vitrinite(average 23.9 %).According to the variation of coal maceral in the vertical profile,coal F has been divided into 1 fourth-order sequence and 5 fifth-order sequences.In the vertical profile,vitrinite content of coal F has a trend of increase as a whole,which reflects the dynamic background of gradual rise of base level rise of the lacustrine transgressive system tract of the third-order sequence SIII6.