摘要
从火山活动至沉积建造的多旋回特点出发,系统论述了冀西北地区中新生代盆地的成生与演化发展,对不同时期盆地的特征进行了分析总结。①区内中生代的构造变动以断裂和局部升降、局部褶皱为主,形成了一系列断陷盆地和继承性拗陷盆地,沉积了巨厚的陆相碎屑岩-火山岩建造,聚煤作用形成于火山活动的间歇期。由于这些盆地形成时代和所处构造环境不同,造成盆地内充填物类型不同。古构造和古气候是决定盆地接受磨拉石建造还是形成含煤建造的主要控制因素。②主要成煤期有中侏罗世下花园期,早白垩世青石砬期。下花园期含煤建造主要分布于燕山台褶带内,青石砬期含煤建造主要赋存于冀北隆起带内,聚煤作用有随时间由南向北迁移的趋势。中侏罗世下花园期盆地多数为断陷盆地,也有少数拗陷盆地,早白垩世青石砬期盆地多数为断陷盆地,但在盆地演化后期,一般的断陷盆地均有向拗陷盆地转化的趋势。中侏罗世下花园期聚煤作用强度大,燕山台褶带内盆地聚煤作用好,拗陷盆地聚煤作用较断陷盆地好。③单盆地聚煤期的充填序列与盆地演化阶段相对应,反应了盆地演化历程,从层序地层角度划分为低位体系域、湖侵体系域、高位体系域。
Start from muhicyclic features of volcanic activities or even sedimentary formations, systematically expounded the formation, evolution and development of Mesozoic and Cenozoic basins in northwestern Hebei Province, and carried out analysis and summarization of different stage basin characteristics. ① Mesozoic tectonic events in the area are mainly faulting and local elevation and subsidence, local folding, and formed a series of fault basins and posthumous down-warped basins, deposited very thick terrestrial clastic rock-volcanic rock formation, coal-forming actions formed in intermittent stage of volcanic activities. Since these basins have different forming ages and structural environments caused different filling material types. Paleostructure and paleoclimate are main controlling factors to determine molasse formation or coal-bearing formation. ② Main coal-forming stages have Middle Jurassic Epoch Xiahuayuan Stage, Early Cretaceous Epoch Qingshila Stage. The Xiahuayuan coal-bearing formation is mainly distributed within the Yanshan platformal fold belt, while the Qingshila coal-bearing formation mainly within the North Hebei uplift belt, the coalaccumulation has a trend of migrating from south to north along with the time. Most Xiahuayuan Stage basins are fault basins, also a few down-warped basins; most Qingshila stage basins are fault basins, but during the later basin evolution, the fault basins have a trend of transformation into down-warped basins generally. Coal-accumulation during Xiahuayuan Stage has a high intensity and a good coal-accumulation in Yanshan platformal fold belt. Coal-accumulation in down-warped basins is better than in fault basins. ③ Coal-accumulation stage filling sequences in a single basin corresponding to evolutionary stages have reflected evolution process. From sequence stratigraphical point of view can be partitioned into lowstand, lacustrine transgression and highstand systems tracts.
出处
《中国煤炭地质》
2012年第9期7-11,19,共6页
Coal Geology of China
关键词
赋煤规律
聚煤盆地
中新生代
冀西北
coal hosting pattern
coal-accumulation basin
.Mesozoic and Cenozoic eras
Northwest Hebei
