基于石榴石的变质岩年代学

程昊, 徐乃潇

Garnet Geochronology of Metamorphic Rocks

Hao Cheng, Naixiao Xu

图4 单颗粒石榴石的Lu-Hf内部等时线 （a）单颗粒石榴石内部连续分带的Lu-Hf两点等时线，等时线较低点为石榴石边部的组成，附图为Fe的X射线分布图，据参考文献[10]修改； (b)单颗粒石榴石内部的12个分区、2个石榴石边部与附着基质的混合物以及全岩的Lu-Hf等时线图，附图内带数字的方块对应石榴石颗粒内Lu-Hf定年的取样区域，据参考文献[11]修改

Fig.4 Lu-Hf isochrons of single garnet grain (a) Lu-Hf garnet-only two-point isochrons of consecutive garnet segments showing the compositions of the rims of the garnets as the lower points of the isochrons. An X-ray map of Fe is also shown. Numbered boxes indicate sampled sections of the garnet crystals for dating, modified after reference[10]. (b) Lu-Hf plots for 12 garnet zones in the garnet grain, two mixtures of garnet rims and adhered matrix, and the whole rock. Numbered boxes in the inset photograph of the garnet porphyroblast indicate sampled sections for Lu-Hf dating, modified after reference[11]