关键词: 郯庐断裂带, 活断层, 拉分盆地, 早白垩世

Abstract: The Shichang Zhonglou basin is situated in the Yihe Shuhe area at the middle section of the Tan Lu fault zone The strike slip Tan Lu fault cuts the Qinling Dabie Jiaonan orogen of Pre Mesozoic,while in the study area the Yihe Shuhe (Yi-Shu) fault overlies the north margin shear zone of the Jiaonan orogen,which gives out an ⁴⁰Ar/³⁹Ar age of 136.2 Ma The faults are unconformably covered with the Qingshan Group of the age of 119 Ma (K-Ar whole rock) These evidence show that the Tan Lu fault had significant strike slip movement The Shichang Zhonglou basin is controlled by the Yihe Shuhe fault,it occurs as a rhombachasm tectonic basin with a length 60 km and a width 30 km The thickness of the Early Cretaceous Laiyang Group in the basin is more than 6263.7m The sedimentation rate is greater than 0.4mm/a The fast changing sedimentary facies in the Laiyang Group reflects that the basin was narrow and deep Migration of the sedimentation center is consistent with the strike slip boundary faults showing the characteristics of "depositing while strike slip moving" It is suggested that the Shichang Zhonglou basin is a pull apart basin formed during the process of sinistrial strike slip movement of the Tan Lu fault zone in early Cretaceous

Key words: Tancheng Lujiang fault zone, Active fault, Pull apart basin, Early Cretaceous