地质通报
地質通報
지질통보
GEOLOGICAL BULLETIN OF CHINA
2014年
7期
1028-1040
,共13页
刘图杰%裴先治%刘成军%李佐臣%李瑞保%魏博%王元元%任厚州%胥晓春%陈伟男
劉圖傑%裴先治%劉成軍%李佐臣%李瑞保%魏博%王元元%任厚州%胥曉春%陳偉男
류도걸%배선치%류성군%리좌신%리서보%위박%왕원원%임후주%서효춘%진위남
LA-ICP-MS锆石U-Pb年龄%形成时代%物源%太阳寺岩组%西秦岭%两当地区
LA-ICP-MS鋯石U-Pb年齡%形成時代%物源%太暘寺巖組%西秦嶺%兩噹地區
LA-ICP-MS고석U-Pb년령%형성시대%물원%태양사암조%서진령%량당지구
LA-ICP-MS zircon U-Pb age%sedimentary age%material source%Taiyangsi Formation%Western Qinling%Liangdang ar ea
选取西秦岭两当地区太阳寺岩组的变质碎屑岩为研究对象，依据CL图像，采用LA-ICP-MS锆石U-Pb同位素定年方法，探讨两当地区太阳寺岩组的形成时代与物源。两当地区太阳寺岩组的锆石U-Pb年龄及与邻近地层的变质变形关系和时代对比表明，太阳寺岩组的沉积时代为426~420Ma，为晚志留世-末志留世。太阳寺岩组的碎屑锆石年龄谱可分为4组：500~420Ma、955~550Ma、1866~1227Ma和3039~2132Ma。早古生代年龄组呈现最强的烈峰值特征，峰值为438Ma，该组锆石物源以西秦岭北缘构造带为主；新元古代年龄组的碎屑锆石物源为西秦岭北缘构造带和北祁连造山带；中元古代和古元古代-新太古代年龄组的碎屑锆石物源主要来自于北祁连造山带和西秦岭北缘构造带基底岩系。综合分析认为，西秦岭北缘构造带为天水两当地区太阳寺岩组碎屑沉积物的主要源区。
選取西秦嶺兩噹地區太暘寺巖組的變質碎屑巖為研究對象，依據CL圖像，採用LA-ICP-MS鋯石U-Pb同位素定年方法，探討兩噹地區太暘寺巖組的形成時代與物源。兩噹地區太暘寺巖組的鋯石U-Pb年齡及與鄰近地層的變質變形關繫和時代對比錶明，太暘寺巖組的沉積時代為426~420Ma，為晚誌留世-末誌留世。太暘寺巖組的碎屑鋯石年齡譜可分為4組：500~420Ma、955~550Ma、1866~1227Ma和3039~2132Ma。早古生代年齡組呈現最彊的烈峰值特徵，峰值為438Ma，該組鋯石物源以西秦嶺北緣構造帶為主；新元古代年齡組的碎屑鋯石物源為西秦嶺北緣構造帶和北祁連造山帶；中元古代和古元古代-新太古代年齡組的碎屑鋯石物源主要來自于北祁連造山帶和西秦嶺北緣構造帶基底巖繫。綜閤分析認為，西秦嶺北緣構造帶為天水兩噹地區太暘寺巖組碎屑沉積物的主要源區。
선취서진령량당지구태양사암조적변질쇄설암위연구대상，의거CL도상，채용LA-ICP-MS고석U-Pb동위소정년방법，탐토량당지구태양사암조적형성시대여물원。량당지구태양사암조적고석U-Pb년령급여린근지층적변질변형관계화시대대비표명，태양사암조적침적시대위426~420Ma，위만지류세-말지류세。태양사암조적쇄설고석년령보가분위4조：500~420Ma、955~550Ma、1866~1227Ma화3039~2132Ma。조고생대년령조정현최강적렬봉치특정，봉치위438Ma，해조고석물원이서진령북연구조대위주；신원고대년령조적쇄설고석물원위서진령북연구조대화북기련조산대；중원고대화고원고대-신태고대년령조적쇄설고석물원주요래자우북기련조산대화서진령북연구조대기저암계。종합분석인위，서진령북연구조대위천수량당지구태양사암조쇄설침적물적주요원구。
Detailed observations of CL images and LA-ICP-MS detrital zircon U-Pb ages of the metasandstone samples from Liang-dang area of Western Qinling provide information about the provenance of Taiyangsi Formation. The ages of detrital zircons show that the sedimentary ages of the Taiyangsi Group range from 426 to 420Ma, suggesting Ludlow to Pridoli period. The U-Pb detrital zircon ages can be assigned to four age groups: 500~420Ma, 955~550Ma, 1866~1227Ma and 3039~2132Ma. Early Paleozoic age group shows the most strong peak age of 438Ma, implying that the material source was mainly from the north margin of Western Qinling tectonic belt. The detrital zircons with Neoproterozoic age were related to the magma of the north margin of Western Qin-ling tectonic belt and Northern Qilian orogenic belt in the Neoproterozoic. The detrital zircons with Mesoproterozoic age and Paleo-proterozoic-Neoarchaean age were mainly from the basement of Northern Qilian orogenic belt and the north margin of Western Qinling tectonic belt. A comprehensive analysis reveals that the material source of Taiyangsi Formation was mainly from the north margin of Western Qinling tectonic belt.
