华南火成岩中捕获锆石的早元古代－太古宙U－Pb年龄信息  

THE U-Pb AGES OF EARLY PROTEROZOIC-ARCHEAN ZIRCONS CAPTURED BY IGNEOUS ROCKS IN SOUTHERN CHINA

作　　者：甘晓春[1,2] 赵风清[1,2] 金文山[1,2] 孙大中[1,2] 

机构地区：[1]德克萨斯大学达拉斯分校,天津地质矿产研究所 [2]中国科学院广州地球化学研究所

出　　处：《地球化学》1996年第2期112-120,共9页Geochimica

摘　　要：本文以火成岩中捕获锆石为测年对象，用单颗粒锆石Ｕ－Ｐｂ稀释法，对华南地区扬子地块南部和华夏地块进行了比较广泛系统的取样和测年工作。测年结果表明，华南地区火成岩中普遍存在早元古代－太古宙的捕获锆石，最大年龄达３．１Ｇａ，表明华南地壳深部在较大范围内存在早元古代－太古宙的地壳再循环物质，华南大陆地壳可能最初形成于３．１Ｇａ之前。根据捕获锆石年龄信息，华南早元古代之前大陆地壳生长集中于～３．１Ｇａ，～２．７Ｇａ，～２．５Ｇａ，～２．２Ｇａ和１．８－２．１Ｇａ几个时期。Zircons captured by igneous rocks during intrusion and/or eruption can give the age in formation of the rocks in deep crust. By means of single zircon dating method, comprehensive geochronological studies on the captured zircons from igneous rocks in southern China are carried out.The 31 age data obtained reveal that there exist extensively Early Proterozoic-Archean crustal materials in the deep crust in southern China, with the oldest zircon of 3.1 Ga. It seems reasonable to assume that the crust in southern China come into being before 3. 1 Ga. According to the ages of captured zircon of this study, the crustal accretion in southern China before Early Proterozoic concentrates on following periods: ～3. 1Ga, ～2.7Ga,～2.5Ga,～2.2Ga and 1.8-2.1 Ga.

关 键 词：火成岩 锆石 铀同位素 铅同位素 年龄测定 

分 类 号：P588.1[天文地球—岩石学] P597[天文地球—地质学]