邵龙义, 华芳辉, 易同生, 郭立君, 王学天. 贵州省乐平世层序–古地理及聚煤规律[J]. 煤田地质与勘探, 2021, 49(1): 45-56. DOI: 10.3969/j.issn.1001-1986.2021.01.005
引用本文: 邵龙义, 华芳辉, 易同生, 郭立君, 王学天. 贵州省乐平世层序–古地理及聚煤规律[J]. 煤田地质与勘探, 2021, 49(1): 45-56. DOI: 10.3969/j.issn.1001-1986.2021.01.005
SHAO Longyi, HUA Fanghui, YI Tongsheng, GUO Lijun, WANG Xuetian. Sequence-paleogeography and coal accumulation of Lopingian in Guizhou Province[J]. COAL GEOLOGY & EXPLORATION, 2021, 49(1): 45-56. DOI: 10.3969/j.issn.1001-1986.2021.01.005
Citation: SHAO Longyi, HUA Fanghui, YI Tongsheng, GUO Lijun, WANG Xuetian. Sequence-paleogeography and coal accumulation of Lopingian in Guizhou Province[J]. COAL GEOLOGY & EXPLORATION, 2021, 49(1): 45-56. DOI: 10.3969/j.issn.1001-1986.2021.01.005

贵州省乐平世层序–古地理及聚煤规律

Sequence-paleogeography and coal accumulation of Lopingian in Guizhou Province

  • 摘要: 利用露头剖面及钻孔资料对贵州省乐平统(上二叠统)含煤岩系层序-古地理及聚煤规律进行研究。根据海相标志层向陆地方向延伸范围所反映的海平面规律,将贵州省乐平统划分为3个三级复合层序(CSⅠ、CSⅡ、CSⅢ)和相应的低位、海侵及高位层序组,层序CSⅠ相当于龙潭组下段中下部,层序CSⅡ相当于龙潭组下段上部及龙潭组上段下部,层序CSⅢ相当于龙潭组上段上部及长兴组。通过分析地层厚度、石灰岩含量、砂泥比、煤层厚度等参数变化规律,恢复3个层序的岩相古地理。贵州省乐平世海侵方向均来自研究区东部,物源来自西部的康滇高地,贵州省地区乐平统自西向东发育有陆相冲积平原、过渡相三角洲及潮坪-潟湖、海相碳酸盐台地以及深水盆地等古地理单元,总体上贵州省乐平世经历了CSⅠ的海侵、CSⅡ的海退及CSⅢ的持续海侵过程,在贵州西部地区,各古地理单元总体上有CSⅠ向陆、CSⅡ向海、CSⅢ又持续向陆的迁移规律。聚煤作用以CSⅢ最强,CSⅡ次之,CSⅠ较差。聚煤中心分布在过渡相三角洲平原及潮坪古地理单元,且有随区域性的海侵海退而迁移。CSⅠ的聚煤中心主要分布在发耳和纳雍地区,CSⅡ的聚煤中心主要分布在黔西南普安—六盘水及织金一带,CSⅢ的聚煤中心主要分布在六盘水、盘县及织金地区。这些聚煤规律分析结果可为煤炭及煤层气资源的勘探开发提供理论支持。

     

    Abstract: Based on outcrop sections and borehole data, the sequence stratigraphy, paleogeography, and coal accumulation of Lopingian(Upper Permian) in Guizhou Province have been studied. According to distribution of marine limestone beds which reflects variation of the transgressions, we have subdivided the Lopingian into 3 third-order composite sequences(CSⅠ, CSⅡ, CSⅢ) and related lowstand, transgressive, highstand sequence sets. CSⅠcorresponds to the lower and middle parts of the Lower Member of Longtan Formation. CSⅡcorresponds to the upper part of the Lower Member of Longtan Formation. CSⅢcorresponds to upper part of the Upper Member of Longtan Formation and Changxing Formation. The paleogeography map of these three sequences are reconstructed based on the contour maps of stratal thickness, percentage of limestones, sandstone to mudstone thickness ratios, and total coal thickness. Transgression direction for the three sequences was from east and the provenance was from western Khangdian Oldland. From west to east, there was a variation in facies units from terrestrial fluvial plain, transitional delta plain and tidal flat-lagoon, marine carbonate platform, to deep water basin. In general, Guizhou Province experienced the transgression of CSⅠ, the regression of CSⅡand the continuous transgression of CSⅡduring the Lopingian. In western Guizhou, each paleogeographic unit migrated landwards in CSⅠ, seawards in CSⅡ, and landwards again in CSⅡ. The coals were mainly formed in the delta plain and tidal flat environments of transitional facies, and the coal-accumulating centers migrated with regional transgression and regression. The coal-accumulating centers of CSⅠwere mainly distributed in the Fa'er and Nayong areas, the coal-accumulating centers of CSⅡwere mainly distributed around the Pu'an-Liupanshui and Zhijin areas, and the coal-accumulating centers of CSⅢwere mainly distributed around Liupanshui, Panxian and Zhijin areas. These results of coal accumulation analysis can provide theoretical support for the exploration and development of coal and coalbed methane resources.

     

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