摘要
根据岩性在垂向上的变化特征,结合煤层的发育情况,伊犁盆地西南缘侏罗系划分为8个沉积旋回。该划分方案主要以地层中比较稳定的煤层做为一个旋回结束的标志,但是在煤层不发育的部位,或者研究区以外的盆地其他地区,在地层划分和对比过程中就会出现人为的不确定性。本文运用旋回地层学理论,利用能敏感地反映岩性尤其是泥、砂含量变化,有效记录地层序列中沉积旋回和沉积环境特点的自然伽马测井曲线,采用累积残差、滤波处理等方法,正弦波拟合等手段,在研究区侏罗系地层识别出了6个完整的向上变细—向上变粗的沉积旋回,以及1个向上变细的正旋回。划分出的沉积旋回在区域内稳定出现,且不受煤层等其他标志层出现或缺失的影响。在侏罗系地层中旋回厚度最大的分布在西山窑组上段,最小的地层分布在三工河组。但是旋回厚度变化最独特的是西山窑组下段,旋回厚度呈阶梯式逐渐增大,而西山窑组下段就是伊犁盆地铀成矿潜力最大的地层。旋回厚度的变化对应沉积速率的变化,由此可以推测沉积速率成阶梯状、逐渐增大的层位,应该是以后找矿工作中的重要目的层。
According to the vertical change characteristics of lithology and the development of coal seam,the Jurassic strata in the southwest margin of Yili basin are divided into 8 sedimentary cycles.The classification scheme marks an end to a cycle just in relatively stable bearing-coal strata,but not in the coal-developing areas,or other areas outside the study area of the basin,the stratigraphic division and correlation in the process will appear artificial uncertainty.Studying sedimentary cycle and deposition rate of Jurassic in the southwestern margin of yili basin,summarizing it's relationship to uranium deposit.Using cyclic stratigraphy theory,cumulative residuals,filter processing methods,sine wave fitting method,in recognition of the Jurassic formations in the study area out of the 6 complete upward fining-toward the table thick sedimentary cycles,and 1 upward fining positive cycle.Sedimentary cycle division of the stability in the region,and is not affected by the presence or absence of coal and other marker bed.In the Jurassic strata,the maximum thickness of the cycle is distributed in Upper Xishanyao Formation,and the smallest is distributed in the Sangonghe Formation.However,the most unique change of cycle thickness is the Lower Xishanyao Formation,the cyclic thickness increases gradually,while the Lower Xishanyao Formation is the largest metallogenic potential of Uranium deposits in Yili basin.The change of cycle thickness corresponds to the change of sedimentary rate,so it can be inferred that the sedimentary rate of a layer is gradually increasing,which should be an important target layer for future prospecting work.
作者
李盛富
陈洪德
邱余波
徐新文
任满船
王谋
LI Sheng-fu;CHEN Hong-de;QIU Yu-bo;XU Xin-wen;REN Man-chuan;WANG Mou(Chengdu University of Technology,Chengdu of Sichuan Prov.610059,China;Geologic Party No.216,CNNC,Urumqi of Xinjiang Prov.830011,China;Beauru of the Nuclear Industry and Geology in Qinghai Province,Xining of Ningxia Prov.810008,China)
出处
《核科学与工程》
CAS
CSCD
北大核心
2018年第5期888-899,共12页
Nuclear Science and Engineering
基金
新疆军民结合产业发展专项资金项目:重点煤炭开发区放射性地质环境现状调查的关键技术研究
国家自然科学基金联合基金(编号:U1403292)
整装勘查区找矿预测与技术应用示范(编号:121201004000150017)
中核集团龙腾项目(编号:地LTD1601-4)等项目联合资助成果
关键词
伊犁盆地
侏罗系
自然伽马测井曲线
频谱分析
沉积旋回
砂岩型铀矿
Yili basin
Jurassic
GR well logging
Spectral analysis
Sedimentary cycle
Sandstone-type Uramium deposit
