胶莱盆地白垩系底部林寺山组砾岩沉积特征及盆地演化意义

发布时间：2018-04-09 18:25

本文选题：胶莱盆地　切入点：白垩系　出处：《中国地质大学(北京)》2015年硕士论文

【摘要】：莱阳群是苏鲁造山带隆升、剥蚀后,分布最广、厚度最大的沉积单位,其底部普遍发育一套底砾岩,命名为“林寺山组”砾岩,该砾岩的出现与造山带的活动密切相关,它的物质组成及沉积特征揭示了苏鲁造山带的演化历史,有助于恢复苏鲁造山带的古地理和古构造演化。通过对盆地及周缘18个地点林寺山组砾岩系统的调查,从砾岩组分、砾径和长轴排列方向的统计分析出发,研究该砾岩沉积相类型、盆地物源区、古水流及林寺山组上覆地层中砂岩碎屑锆石U-Pb年龄谱特点,并进一步讨论了盆地演化的意义。研究表明:(1)胶莱盆地林寺山组粒径均值主要集中在-2.00~-3.86(4cm~14.6cm),个别粒径达到-6.29(78cm)。标准方差、偏度、峰度的范围分别为0.82~1.21,-0.11~0.12,0.82~1.28,各个砾石测点之间存在差异性,反应它们形成环境的异同性。(2)林寺山组底部砾岩以冲积扇相为主,但不同地点亚、微相类型又有差异,黄崖底地区为干旱型冲积扇沉积,下部为扇根亚相,多为泥石流沉积,夹少量河道沉积,上部为扇中或扇端亚相,多为河道沉积和河道间湾沉积;山角、郭城镇、朱吴镇等地为干旱型冲积扇沉积,下部多为扇根亚相,泥石流沉积,上部为扇中亚相,以筛状沉积为主,夹漫流沉积和河道沉积;盆地南缘皇华镇和许孟镇地区为湿润型冲积扇沉积,下部为扇根亚相,泥石流沉积,上部为扇中亚相,河道沉积与筛状沉积交互出现,顶部为扇端亚相,河道沉积为主;五莲、桑园镇、柳黄沟地区下部为湿润型冲积扇扇根亚相,泥石流沉积,上部为近源扇三角洲相,以水下辩状河道沉积为主。(3)原型胶莱盆地由莱阳、海阳-即墨和诸城-五莲三个独立盆地组成,被6个隆起区所分隔。(4)莱阳盆地的物源区主要为胶北隆起和苏鲁造山带北部隆起;海阳—即墨盆地中海阳地区以苏鲁造山带北部隆起和即墨—牟平隆起为主物源区,即墨地区以胶南隆起为主物源区;诸城—五莲盆地以胶南隆起和马山—李家党低隆起为主要物源区。(5)早白垩世中期(约130Ma)为一重要构造转换时期,标志着胶莱盆地的形成及苏鲁造山带大规模塌陷成盆作用的启动。
[Abstract]:In this paper , the authors studied the characteristics of zircon U - Pb ages of sandstone in the overlying strata in the basin and the surrounding area . The results show that : ( 1 ) The average particle size of the Lingji Mountain Formation in the Jiaolai Basin is in the range of - 2.00 ~ - 3.86 ( 4cm ~ 14.6 cm ) , and the individual particle size reaches - 6.29 ( 78cm ) . The standard variance , deviation and peak value are 0.82 ~ 1.21 , - 0.11 ~ 0.12 , 0.82 ~ 1.28 respectively . ( 2 ) At the bottom of Lingji Mountain Formation , the conglomerate is dominated by alluvial fan . However , there are different types of sub - facies and facies in Huangya area . The lower part is fan - root sub - facies , and the upper part is fan - root sub - facies . The upper part is fan - root sub - facies . The upper part is fan - root sub - facies , and the upper part is fan - root sub - facies . The upper part is fan - root sub - facies . The upper part is fan - root sub - facies . The upper part is fan - root sub - facies . The upper part is fan - root sub - facies . The upper part is fan - root sub - facies . The upper part is fan - root sub - facies . The upper part is fan - root sub - facies , and the upper part is fan - root sub - facies . ( 5 ) Early Cretaceous ( about 130Ma ) is an important tectonic transition period , marking the formation of Jiaolai basin and the start of the large - scale collapse of Sulu orogenic belt .

【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P588.212.5;P548

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