We report in-situ dating, and Hf and O-isotope studies of zircon crystals, together with electron microprobe imaging of garnet crystals from a migmatitic diorite containing noritic globules, in the Ursuya massif (French Pyrenees). Diorite zircon crystals have old inherited cores and 295 ± 2 Ma rims, while those in the norite are homogeneous, with lower U and Pb, and higher Th and Th/U ratios than in the diorite zircon rims. The 295 Ma dates represent the crystallization age of hybridised crustal melts. Norite zircon crystals have similar ages (298 ± 3 Ma) to the diorite zircon rims, interpreted as the crystallization age of the norite. Hf isotopes indicate that the noritic magmas were already crustally contaminated prior to intrusion at their present locations. The contrasting behaviours of slow- and fast-diffusing species within garnet (e.g. P vs Ca) caused sharp P and diffuse Ca core-rim transitions. Modelling of garnet Ca diffusion profiles suggests a duration of 2 ± 1 Myr for the magma interactions in the deep crust. Integrated with granite dating, these data provide insights into pulsations in the regional thermal event that concluded the Hercynian orogenic cycle.

我们报告原位测年和锆石晶体的Hf和O同位素研究，以及在Ursuya地块（法国比利牛斯山）中从含有诺富特小球的隐影闪长岩中形成的石榴石晶体的电子微探针成像。闪长锆石晶体具有较旧的继承核，且具有295±2 Ma的边缘，而在红宝石中则是均质的，与闪长锆石边缘相比，其具有较低的U和Pb以及较高的Th和Th / U比。295 Ma的日期代表了混合的地壳熔体的结晶年龄。氧化锆石晶体的年龄（298±3 Ma）与闪锌矿锆石的边缘相似，这被解释为氧化锆石的结晶年龄。f同位素表明，在侵入它们的当前位置之前，它们已经被地壳污染。石榴石中慢速扩散和快速扩散物种的对比行为（例如 P vs Ca）导致尖锐的P和扩散的Ca核-边缘跃迁。石榴石钙扩散曲线的模型表明深壳中的岩浆相互作用的持续时间为2±1 Myr。与花岗岩测年相结合，这些数据提供了对结束海西造山运动周期的区域性热事件中脉动的洞察力。