CAJ | 학술논문

在济南南部下寒武统朱砂洞组丁家庄段硅质白云岩中，发育地震引起的硅质触变脉、硅质触变沉陷构造和触变楔等软沉积变形构造。从同一地震触变沉陷构造中，采得一组灰黑色燧石样品。使用英国 VG354同位素质谱仪和同位素质谱分析方法，测得每个样品的147Sm／144Nd 和143Nd／144Nd 同位素值。采用 Sm-Nd 等时线法，对燧石进行了测年。获得燧石的成岩年龄为530．8±6．1, Ma，由于软燧石（硅胶体）成岩至少经历了0．1 Ma的时间，所以，地震沉积事件发生在530．7±6．1 Ma，属早寒武世早期。由于测年结果与沧浪铺阶的下界年龄接近，山东朱砂洞组丁家庄段无化石且河南省标准地层剖面中的整个朱砂洞组属沧浪铺阶，这暗示济南地区朱砂洞组丁家庄段属沧浪铺阶。本次测年得到了鲁西地区第1个下寒武统的同位素年龄值，这对确定该地区早寒武世地震沉积事件发生的时间具有参考价值和意义，也为深入研究鲁西地区寒武纪地层提供了新资料。
재제남남부하한무통주사동조정가장단규질백운암중，발육지진인기적규질촉변맥、규질촉변침함구조화촉변설등연침적변형구조。종동일지진촉변침함구조중，채득일조회흑색수석양품。사용영국 VG354동위소질보의화동위소질보분석방법，측득매개양품적147Sm／144Nd 화143Nd／144Nd 동위소치。채용 Sm-Nd 등시선법，대수석진행료측년。획득수석적성암년령위530．8±6．1, Ma，유우연수석（규효체）성암지소경력료0．1 Ma적시간，소이，지진침적사건발생재530．7±6．1 Ma，속조한무세조기。유우측년결과여창랑포계적하계년령접근，산동주사동조정가장단무화석차하남성표준지층부면중적정개주사동조속창랑포계，저암시제남지구주사동조정가장단속창랑포계。본차측년득도료로서지구제1개하한무통적동위소년령치，저대학정해지구조한무세지진침적사건발생적시간구유삼고개치화의의，야위심입연구로서지구한무기지층제공료신자료。
In southern Jinan area,some soft sediment deformation structures triggered by earthquake developed in siliceous dolostone layers of the Dingjiazhuang Member of the Lower Cambrian Zhushadong Formation,such as siliceous thixotropic veins,siliceous thixotropic subsidence and wedge,etc.A set of gray black cherts were sampled from the same soft-siliceous subsidence structure.Using the VG354 isotopic mass spectrometer (made in Britain)and the method of isotope mass spectrometry,the 147Sm/144Nd and 143Nd/144Nd isotope ratios of each samples were measured.By means of the Sm-Nd isochron,the cherts have been dating.The diagenetic ages of the 530. 8±6. 1 , Ma were obtained for the set of gray black cherts, belonging to the early stage of the Early Cambrian.As the minimum time for a soft flint (colloidal silica)to form a lithified rock is 0. 1 Ma,it can be inferred that the seismic sedimentary events occurred at 530. 7± 6. 1 Ma.Since the dating result is close to the lower bound age of the Canglangpuan Stage,and there is exists no fossil in the Dingjiazhuang Member of the Zhushadong Formation of Shandong Province,and the whole Zhushadong Formation belongs to the Canglangpuan Stage in the key profile of the Zhushadong For-mation of Henan Province.So it is implied that the Dingjiazhuang Member of the Zhushadong Formation belongs to the Canglangpuan Stage.Through dating,the first isotopic age of the Lower Cambrian of the western Shandong is got,which is possessed of some reference value and significance to define the time of seismic depositional events in the Early Cambrian,and also provides a new datum for the further study of the Cambrian strata in the area.