Late Variscan metamorphic and magmatic evolution in the eastern Pyrenees revealed by U–Pb age zircon dating

Variscan migmatites cropping out in the eastern Pyrenees were dated together with Late Variscan plutonic rocks. Upper Proterozoic–Lower
Cambrian series were migmatized during a thermal episode that occurred in the interval 320–315 Ma coeval with the main Variscan
deformation event (D1). The calc-alkaline Sant Llorenç–La Jonquera pluton and the gabbro–diorite Ceret stock were emplaced during a later thermal
episode synchronous with the D2 deformation event. A tonalite located at the base of La Jonquera suite intruded into the upper crustal levels between 314
and 311 Ma. The gabbro–diorite stock was emplaced in the middle levels of the series in two magmatic pulses at 312 and 307
Ma. The thermal evolution recorded in the eastern Pyrenees can be correlated with that of neighbouring areas of NE Iberia
(Pyrenees–Catalan Coastal Ranges) and SE France (Montagne Noire). The correlation suggests a NW–SE-trending zonation where
the northeasternmost areas (Montagne Noire and eastern Pyrenees) would occupy relatively more internal zones of the orogen
than the southwesternmost ones.

在东部比利牛斯山脉中出露的Variscan混合岩与晚期的Variscan岩浆岩同时进行了年代测定。在约3.2亿至3.15亿年前，上元古宙至下寒武纪地层在一场热事件中发生了混合岩化，该事件与主要的Variscan变形事件（D1）同期发生。calc-alkaline类型的Sant Llorenç–La Jonquera岩浆岩以及橄榄辉长岩-辉长岩的Ceret岩株是在随后的热事件中，与D2变形事件同步形成的。位于La Jonquera套系底部的花岗岩在3.14亿至3.11亿年前侵入到上地壳层。橄榄辉长岩岩株在3.12亿和3.07亿年前通过两次岩浆脉冲在中部层位形成。东部比利牛斯山脉记录的热演化过程可以与东北伊比利亚邻近地区（比利牛斯山脉-加泰罗尼亚沿海山脉）以及东南法国（蒙塔涅·诺埃尔）的热演化过程相对应。这种相关性暗示了一个西北-东南走向的带状分布，其中最北部的地区（蒙塔涅·诺埃尔和东部比利牛斯山脉）相对于最西南部的地区，将占据造山带内部较为核心的区位。