Chemical (non-isotopic) and isotopic dating of Phanerozoic zircon—A case study of durbachite from the Třebíč Pluton, Bohemian Massif
Chemical (non-isotopic) and isotopic dating of Phanerozoic zircon—A case study of durbachite from the Třebíč Pluton, Bohemian Massif
复制标题
DOI：
10.1016/j.gr.2009.06.005
复制
发表时间：
2010
影响因子：
6.1
通讯作者：
M. Kusiak;D. Dunkley;Kazuhiro Suzuki;V. Kachlík;Artur Kędzior;J. Lekki;S. Opluštil
中科院分区：
文献类型：
--
作者：
M. Kusiak;D. Dunkley;Kazuhiro Suzuki;V. Kachlík;Artur Kędzior;J. Lekki;S. Opluštil
独居石电子探针U-Th-Pb化学（非同位素）定年法虽然已经成熟，但对锆石的定年仍存在争议。来自Tubebín Pluton的相对富含铀的锆石（高达2500 ppm的铀）为该技术提供了一个测试案例。锆石颗粒通常是部分或完全变质的，因此容易受到铅的损失和常见的铅污染。以Ca、K含量作为指示锆石损伤或污染的指标，对<0.03wt.%的锆石进行CHIME（化学U-Th-total Pb法）测年，得到347.8± 18 Ma CaO和K_2O，且>0.0062wt.%的PbO。经SHRIMP同位素测年（341.6±2.8Ma）证实了这一年龄。这些结果与先前估计的时间durbachitic侵入到华力西造山带的根和华力西基底纳入西阿尔卑斯山，343和332马之间。
Although chemical (non-isotopic) U–Th–Pb dating of monazite by electron microprobe is well-established, dating of zircon by this method is still controversial. Relatively U-rich zircon (up to 2500ppm of U) from the Třebíč Pluton provides a test case for the technique. Zircon grains are commonly partially or completely metamict, and therefore susceptible to Pb loss and common Pb contamination. Using Ca and K contents as indicators of damaged or contaminated zircon, a CHIME (Chemical U–Th–total Pb method) age of 347.8±18Ma was obtained from data with <0.03wt.% of CaO and K2O, and >0.0062wt.% of PbO. This age was confirmed by isotopic U–Pb SHRIMP dating (341.6±2.8Ma). These results are in agreement with previous estimates for the timing of durbachitic intrusions into the root of the Variscan orogen and from the Variscan basement incorporated into Western Alps, between 343 and 332Ma.