太原西山煤田新生代隆升史的磷灰石裂变径迹约束

发布时间：2018-06-23 07:15

本文选题：太原西山煤田 + 磷灰石裂变径迹　；参考：《地质学报》2017年01期

【摘要】：位于吕梁山中段东缘的太原西山煤田不但是我国重要的炼焦煤基地,同时也是煤层气开发基地。多年开发实践表明该煤田煤层气分布非均质性强、无气-低产井比例高,因此理解控制该煤田煤层气分布的地质因素是预测富集高产区的基础。由于构造抬升不利于煤层气的保存,因此认识煤层生气高峰后的隆升史可以确定煤层气保存的关键时期。通过太原西山煤田晚古生代含煤岩系标志层的5件砂岩样品的磷灰石裂变径迹测年及热历史模拟分析,结合前人在西山煤田西北部边缘及西部吕梁山中段核部前寒武基底地层的磷灰石热年代学数据,可以确定,该煤田在46±4~52±6Ma左右抬升退出磷灰石退火带,而核部前寒武基底地层则在早白垩世已抬升退出磷灰石退火带,吕梁山具有核部抬升早、边缘抬升晚的特点。自新生代以来,太原西山煤田经历了3个抬升阶段:48Ma以前的快速抬升,48±4~10±2Ma的缓慢抬升和10±2Ma以来的剧烈抬升,与前人获得的吕梁山存在缓慢抬升(120~65 Ma)、加速抬升(65~23 Ma)及强烈抬升(23 Ma以来)3个隆升演化阶段相比具有较大的差异,表明吕梁山不同部位具有不同的隆升史。10Ma以后的剧烈抬升与晋中盆地成盆及快速堆积期相一致,它们具有盆山耦合关系,该阶段也是西山煤田煤层气保存的关键时期。
[Abstract]:Taiyuan Xishan coalfield located in the eastern edge of Luliangshan Mountain is not only an important coking coal base but also a coal bed methane development base. The development practice for many years shows that the coalbed methane distribution in this coalfield has strong heterogeneity and the ratio of no gas to low production well is high. Therefore, understanding the geological factors controlling the distribution of coalbed methane in the coalfield is the basis of predicting the high yield and enrichment area. Since tectonic uplift is not conducive to the preservation of coalbed methane, the understanding of the uplift history after the peak of coal seam gas generation can determine the key period of coal bed methane preservation. Through apatite fission track dating and thermal history simulation analysis of 5 sandstone samples of late Paleozoic coal-bearing strata in Xishan coalfield, Taiyuan, China. Combined with the apatite thermochronological data of the Precambrian basement strata in the core of the northwest margin of the Xishan coalfield and the central segment of the western Luliangshan, it can be determined that the coalfield uplifted from the apatite annealing zone at about 46 卤40.52 卤6Ma. The Precambrian basement of the nuclear part was uplifted and exited from the apatite annealing zone in the early Cretaceous, and Luliangshan was characterized by early nuclear uplift and late marginal uplift. Since the Cenozoic, the Xishan coalfield in Taiyuan has experienced three uplift stages: rapid uplift of 48 卤4 10 卤2 Ma and violent uplift since 10 卤2 Ma. There are significant differences between the three uplift evolutionary stages of Luliangshan, namely slow uplift (120 ~ 65 Ma), accelerated uplift (65 ~ 23 Ma) and strong uplift (since 23 Ma). The results show that the uplift in different parts of Luliangshan is consistent with the basin-forming and rapid accumulation periods of Jinzhong basin after 10 Ma, and they have basin-mountain coupling relationship, which is also the key stage of coalbed methane preservation in Xishan coalfield.
【作者单位】：煤与煤系气地质山西省重点实验室;太原理工大学地球科学与工程系;
【基金】：山西省煤基科技攻关项目(M2014-01) 山西省基础研究计划-省青年科技研究基金(编号:2015021171);山西省基础研究计划煤层气联合研究基金(编号:2015012007) 太原理工大学校基金(2015QN048)资助的成果
【分类号】：P618.13

【相似文献】