U-Pb zircon and Sm-Nd dating of Moldanubian HP/HT granulites from South ohemia, Czech Republic
U-Pb zircon and Sm-Nd dating of Moldanubian HP/HT granulites from South ohemia, Czech Republic
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捷克共和国南奥米亚摩尔达努比亚 HP/HT 麻粒岩的 U-Pb 锆石和 Sm-Nd 定年
DOI：
10.1144/gsjgs.151.1.0083
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发表时间：
1994
影响因子：
2.7
通讯作者：
W. Todt
中科院分区：
文献类型：
--
作者：
J. Wendt;A. Kröner;J. Fiala;W. Todt
本文给出了不含辉石、长英质、含石榴石麻粒岩和含斜方辉石麻粒岩的常规多颗粒锆石U-Pb系统学和单颗粒锆石蒸发数据，并结合ND模式年龄对S波希米亚空旷的L-S山脉麻粒岩中的长英质、镁铁质和中间成分麻粒岩进行了研究。来自镁铁质和中麻粒岩的锆石的Concordia截距年龄为346±5~351±6 Ma，单颗粒蒸发年龄为346±12 Ma。这些年龄确定了S波西米亚地区华力西高级变质作用的时代，并得到了343±21 Ma的内部Sm-ND石榴石-锆石-斜长岩-全岩等时线年龄的支持。来自可能花岗质起源的长英质麻粒岩的真面体锆石U-Pb年龄分别为366±5 Ma和373±12 Ma，可解释为花岗岩前驱体的侵入年龄。1700 Ma左右Concordia上交点年龄和1.3~2.1Ga之间的ND模式年龄记录了一个继承的元古界地壳成分。
Conventional multigrain U-Pb systematics of zircon and single-grain evaporation data of zircons in combination with Nd model ages are presented for pyroxene-free, felsic, garnetiferous granulites and orthopyroxene-bearing granulites of felsic, mafic and intermediate composition from the Blansky Lés mountains granulite complex, S Bohemia. Zircons from mafic and intermediate granulites yield Concordia intercept ages between 346 ± 5 and 351 ± 6 Ma as well as a single-grain evaporation age of 346 ± 12 Ma. These ages define the time of Variscan high-grade metamorphism in S Bohemia and are supported by an internal Sm-Nd garnet-zircon-plagioclase-whole rock isochron age of 343 ± 21 Ma. Euhedral zircons from felsic granulites of probable granitic derivation yield U-Pb ages of 366 ± 5 Ma and 373 ± 12 Ma interpreted as intrusion ages of the granitic precursor. An inherited Proterozoic crustal component is documented by poorly defined Concordia upper intercept ages around 1700 Ma and Nd-model ages between 1.3 and 2.1 Ga.