Framework of Sequence Stratigraphy , Sedimentary System and Evolution of Cretaceous Hefei Basin
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摘要: 合肥盆地的白垩系是叠置在侏罗纪前陆盆地上的断陷构造层,其层序地层及沉积演化研究是油气勘探的重要环节。综合应用横跨盆地二维地震剖面、测井、岩芯、露头及其它分析化验资料,对合肥盆地白垩纪的地层进行了层序地层界面的识别、划分,建立了该期地层格架。共划分出一级层序:构造层序界面(构造层序)界面2个:SBK1(TK1)、SBE(TE);二级层序(层序组)界面1个:SBK2(TK2);三级层序(层序)界面4个:SBK11(TK11)、SBK12(TK12)、SBK13(TK13)、SBK21(TK21)。在此基础上建立了合肥盆地白垩纪层序地层格架及沉积演化阶段:早白垩世层序组(包括朱巷组和响导铺组层序组):为西缓超东陡深的不对称箕状断陷格局,西南部和北西部各发育一个大型冲积扇—冲积平原—三角洲平原带,西南部冲积扇—冲积平原大部分已经被剥蚀殆尽;东部和东北部发育一系列扇三角洲构成扇三角洲平原(裙),两者之间为滨浅湖—半深湖—深湖。晚白垩世层序组(张桥组层序组):北断南超的格局占主导,早白垩世时期的大型三角洲体系域已经不复存在,代之而起的是北部发育较大规模的扇三角洲平原;而南部或西南部冲积扇—冲积平原—三角洲平原带已经大为缩小到信阳—舒城断裂北缘。Abstract: According to seismic, welllogs, outcrop & cores data, we identified sequence stratigraphy boundarys. CretaceousPaleogene strata can be recognized as 3 firstorder sequence, 1 secondorder sequences and 4 thirdorder sequences. Based on the principle of base level cycles,the author distinguished & established sequence stratigraphy framework, sedimentary system setting & evolution in CretaceousPaleogene.That is: 1) Early Cretaceous sequence series(Zhuxiang & Xiangdaopu Formations): a semigraben basin which onlapped in the west & faulted in the east, developed great scale alluvial fanalluvial plaindelta plain on the westernnorthern & westernsouthern respecially. On eastern & easternnorthern growth aseries fandeltas & shore semideepdeep lacustrine. 2) Late Cretaceous sequence series(Zhangqiao Formation): similar with Early Cretaceous basically,buta semigraben basin which onlapped in the south & faulted in the north more salience.3) Paleogene Sequence series(Dingyuan Formation): The north of Feizhong fault uplift since tectonic movement so that bisect the basin, Dingyuan depression on the north and Shucheng depression on the south.
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Key words:
- Hefei Basin /
- Cretaceous /
- sequence stratigraphy /
- Zhuxiang Formation /
- Xiangdaopu Formation /
- Zhangqiao Formation
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