The sequence stratigraphy of the Middle Jurassic coal measures in the Laogaoquan region of the northern Qaidam basin
The sequence stratigraphy of the Middle Jurassic coal measures in the Laogaoquan region of the northern Qaidam basin
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发表时间：
2007
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通讯作者：
J. Qi
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作者：
J. Qi
利用钻孔资料对柴达木盆地北部老高泉地区侏罗系煤系的沉积学、层序地层学和成煤规律进行了研究。分析了煤层在不同沉积环境和层序格架中的分布。确定了22个岩相，重建了三角洲平原、滨浅湖、湖相沙坝3个古地理单元。进一步划分了三个三阶序列和相应的系统域。聚煤主要发生在三阶层序的TST和HST，厚煤层倾向于在三阶最大泛洪面附近发育。认为湖相、三角洲平原分流间湾、曲流河后沼泽发育的古成岩是老高泉地区成煤的主要环境，主要煤层（M7）发育在最大泛洪面附近的晚海侵体系域和早期高地体系域。
Sedimentology,sequence stratigraphy and coal accumulation of the Jurassic coal measures in the Laogaoquan region of the northern Qaidam basin were studied using borehole data.The distribution of coal seams in different sedimentary environments and in the sequence framework was analyzed.A total of 22 lithofacies was identified and three palaeogeographical units,including delta plain,littoral and shallow lake,and lacustrine sand bars,were reconstructed.Three third-order sequences and corresponding systems tracts were subdivided.Coal accumulation occurred in the TST and the HST of the third-order sequence,and the thick coal seams tend to develop around the third-order maximum flooding surface.It is suggested that the palaeomires developed from the lacustrine,the interdistributary bay of the delta plain,and the back swamp of meandering rivers are the main environments for coal accumulation in the Laogaoquan area,and the major coal seam(M7),is developed in the late transgressive systems tract and the early highstand systems tract,around the maximum flooding surface.