【摘要】 在诸城断陷皇华镇大山村黄龙沟存在丰富的、多样的恐龙足迹化石,在紧邻化石埋藏层下伏及上覆地层中发现了下白垩统莱阳群杨庄组多套古地震记录,主要包含波状褶皱、底劈构造、液化砂岩脉、液化角砾岩、粒序断层、卷曲变形和震积不整合等塑性、脆性软沉积物变形构造。分析表明初始沉积物、沉积相及构造作用确定了地震活动作用时形成的软沉积物变形构造类型。在早白垩世莱阳群沉积中期,地震活动具有阶段性及频发性,以单向挤压的丘-槽构造及双向挤压的波状变形为主,且后期有构造活动强度加大的特征。根据已识别的古地震记录发育及古地震活动强度分析,推测此时期发震断裂可能是断陷的南缘断裂——五莲断裂。区域构造作用使得该时期沉积环境发生变化,由湖相逐渐过渡到河流相,在突发古地震事件发生之后,在滨浅湖区域留下了丰富的恐龙迁徙足迹。古地震记录的研究,可建立古地震事件与沉积、构造演化的联系,约束构造作用的属性、频次及时限,为确定盆地及周缘构造-沉积演化历史提供证据。更多还原

【Abstract】 Unusual,abundant dinosaur tracks have been discovered in Huanglonggou of Huanghua County in Jiaodong peninsula,eastern China.The tracks wee found to occur in the Yangzhuang Formation of Early Cretaceous Laiyang Group in south of Zhucheng faulted depression in Jiaolai basin.In this study,several sets of paleo-earthquake records were found in the Yangzhuang Formation immediately in underlying and overlying track-bearing strata.Soft-sediment deformation structures include undulate fold,diapir,liquefied sand vein,liquefied breccias,convolute deformation and seismite unconformity,and graded faults.Our analysis shows that initial sediments,sedimentary facies and tectonism determined structural deformation styles of soft sediments produced by seismic activities.During interim of sedimentation of early Cretaceous Laiyang Group,earthquakes were characterized by multiple periods and frequent occurrences,with unilateral compressional dome-trough structure and bi-directional compressional wavy deformation being predominant,and by increasing tectonic activities at late stage.Based on the identified paleo-earthquake development records and their magnitude analysis,it can be assumed that seismogenic fault was likely the Wulan fault,the southern segment of faulting in this period.Regional tectonic effect caused the change of sedimentary environments gradually from lacustrine to fluvial facies,and after outbreak of paleo-earthquakes,abundant tracks of dinosaur migration were left and preserved on lacustrine area.Paleo-seismic records can help built the link between paleo-earthquake events and deposition environment and tectonic evolution,and constrain attributes,frequencies and time-limit of tectonism,thus providing the evidence for determination of basin,surrounding structure and sedimentary development更多还原