地质通报
地質通報
지질통보
GEOLOGICAL BULLETIN OF CHINA
2014年
7期
1015-1027
,共13页
王元元%裴先治%刘成军%李瑞保%李佐臣%魏博%任厚州%陈伟男%刘图杰%胥晓春
王元元%裴先治%劉成軍%李瑞保%李佐臣%魏博%任厚州%陳偉男%劉圖傑%胥曉春
왕원원%배선치%류성군%리서보%리좌신%위박%임후주%진위남%류도걸%서효춘
碎屑锆石%舒家坝群%形成时代%物源%构造环境%西秦岭
碎屑鋯石%舒傢壩群%形成時代%物源%構造環境%西秦嶺
쇄설고석%서가패군%형성시대%물원%구조배경%서진령
detrial zircons%Shujiaba Group%material source%sedimentary age%West Qinling tectonic zone
以西秦岭舒家坝地区泥盆纪舒家坝群碎屑岩为研究对象，进行碎屑锆石LA-ICP-MS U-Pb年龄研究，探讨其形成时代、物源组成和构造背景。所测样品最小锆石年龄组的年龄加权平均值为413Ma，代表了舒家坝群的沉积下限，结合前人研究的古生物资料将其形成时代限定为中泥盆世。所获碎屑锆石年龄可划分为4个谱段：震旦纪-古生代年龄谱段619~409Ma，峰值为445Ma；新元古代年龄谱段930~735Ma，峰值为849Ma；中元古代年龄谱段1760~1033Ma；新太古代-古元古代年龄谱段3095~2478Ma。综合研究认为，舒家坝群的物源具多元性，包括西秦岭北缘构造带、北祁连造山带东段和华北板块基底，其中北祁连造山带东段和西秦岭北缘构造带是舒家坝群沉积的主要物源区，且后者占主导地位。结合区域地质资料，根据其物源组成特征判断，舒家坝群形成于陆-陆或弧-陆碰撞后由挤压转换为伸展环境的局部裂陷盆地。
以西秦嶺舒傢壩地區泥盆紀舒傢壩群碎屑巖為研究對象，進行碎屑鋯石LA-ICP-MS U-Pb年齡研究，探討其形成時代、物源組成和構造揹景。所測樣品最小鋯石年齡組的年齡加權平均值為413Ma，代錶瞭舒傢壩群的沉積下限，結閤前人研究的古生物資料將其形成時代限定為中泥盆世。所穫碎屑鋯石年齡可劃分為4箇譜段：震旦紀-古生代年齡譜段619~409Ma，峰值為445Ma；新元古代年齡譜段930~735Ma，峰值為849Ma；中元古代年齡譜段1760~1033Ma；新太古代-古元古代年齡譜段3095~2478Ma。綜閤研究認為，舒傢壩群的物源具多元性，包括西秦嶺北緣構造帶、北祁連造山帶東段和華北闆塊基底，其中北祁連造山帶東段和西秦嶺北緣構造帶是舒傢壩群沉積的主要物源區，且後者佔主導地位。結閤區域地質資料，根據其物源組成特徵判斷，舒傢壩群形成于陸-陸或弧-陸踫撞後由擠壓轉換為伸展環境的跼部裂陷盆地。
이서진령서가패지구니분기서가패군쇄설암위연구대상，진행쇄설고석LA-ICP-MS U-Pb년령연구，탐토기형성시대、물원조성화구조배경。소측양품최소고석년령조적년령가권평균치위413Ma，대표료서가패군적침적하한，결합전인연구적고생물자료장기형성시대한정위중니분세。소획쇄설고석년령가화분위4개보단：진단기-고생대년령보단619~409Ma，봉치위445Ma；신원고대년령보단930~735Ma，봉치위849Ma；중원고대년령보단1760~1033Ma；신태고대-고원고대년령보단3095~2478Ma。종합연구인위，서가패군적물원구다원성，포괄서진령북연구조대、북기련조산대동단화화북판괴기저，기중북기련조산대동단화서진령북연구조대시서가패군침적적주요물원구，차후자점주도지위。결합구역지질자료，근거기물원조성특정판단，서가패군형성우륙-륙혹호-륙팽당후유제압전환위신전배경적국부렬함분지。
Choosing the Shujiaba Group detrital rocks in Shujiaba area as the study object and using LA-ICP-MS zircon U-Pb isotope chronology, the authors studied the sedimentary age and material source of the Shujiaba Group. 413Ma, the mean of the minimum ages group, indicates that the sedimentary age of Shujiaba Group should be the Middle Devonian. Four groups can be recognized from the zircon ages spectrum:Sinian-Early Paleozoic age group (619~409Ma), with the peak value of 445Ma;Neopro-terozoic age group (930~735Ma), with the peak value of 849Ma; Mesoproterozoic age group (1760~1033Ma); and Paleoproterozo-ic-Neoarchaen age group (3095~2478Ma). The age group information indicates that the material sources were mainly derived from North Qilian orogenic belt ,the northern margin of West Qinling tectonic zone and the basement of North China block, of which the North Qilian orogenic belt and the northern margin of West Qinling tectonic zone made the major contribution, with the last one playing the leading role. The material source features and regional geology suggest that the Shujiaba Group was formed in a rifted basin resulting from the transitional tectonic setting from syn-collision (compressional setting) to post-collision (extensional setting).
