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报道德国黑森林地区（BF）华力西造山带高级变质基底的基性麻粒岩中锆石和石榴石年龄,并讨论其同位素体系的封闭温度.采用锆石U-Pb和Pb-Pb蒸发法分析,得到340 Ma左右至414 Ma的207Pb/206Pb年龄,而且大部分集中在340Ma左右.而石榴石的Sm-Nd和Pb-Pb等时线年龄分别为（398±3）和（411±14）Ma,老于大部分的锆石年龄.这一现象暗示,在340Ma左右的麻粒岩相变质作用（800℃左右）过程中,可能由于重结晶作用或蜕晶作用使大部分锆石丢失其放射成因Pb.而石榴石的Sm-Nd和U-Pb同位素体系保存了变质作用峰期之前的年代学信息.这一现象可能说明该变质作用是在无流体参与的条件下进行的.该实例表明,采用Sm-Nd和U-Pb方法对高级变质岩石定年,在某些情况下石榴石可能是更好的候选矿物.
This paper reports the age of zircon and garnet in the basic metamorphic basement of the metamorphic basement in the Warisi orogenic belt in the Black Forest (BF), Germany, and discusses the sealing temperature of the isotope system.Using zircon U-Pb and Pb-Pb evaporation , The 207Pb / 206Pb ages of 340 Ma to 414 Ma are obtained, most of which are concentrated at about 340 Ma, while the Sm-Nd and Pb-Pb isochron age of garnets are (398 ± 3) and (411 ± 14) ) Ma, which is older than most zircons, suggests that during the granulite facies metamorphism (around 800 ℃) around 340 Ma, most of the zircon may be lost due to recrystallization or decoloration The genesis of radiogenic Pb and the Sm-Nd and U-Pb isotopic compositions of garnet preserve the chronological information before the metamorphic peak, which may indicate that the metamorphism was carried out in the absence of fluid. The examples show that dating of the advanced metamorphic rocks using the Sm-Nd and U-Pb methods may in some cases be a better candidate mineral.