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滇东北与峨眉山大火成岩省有关的自然铜矿化分布于鲁甸、茂林和迤车向斜的二叠纪玄武岩与上覆宣威组地层之间。与自然铜矿化有关的蚀变矿物———浊沸石(LD-14-3、YSD-1和YC-1)均给出了一致的40Ar/39Ar坪年龄和等时线年龄(226～228Ma)。这类矿物不存在Ca和Cl的干扰,是合适的40Ar/39Ar定年对象。但它们的Ar封闭温度较低,在100～110℃之间。所得年龄代表了第一次成矿作用的年龄。片沸石的Ar封闭温度低于70℃,无Cl干扰的片沸石LG-2给出了(134.0±1.7)Ma的40Ar/39Ar稳定坪年龄,并与U-Th-Pb等时线定年结果相一致,表明该区在白垩纪早期存在第二次低温热液作用和自然铜矿化。因此无氯沸石40Ar/39Ar定年可广泛应用于低温变质作用和冷却热历史研究。38Ar含量高的阳起石和片沸石样品存在Cl干扰对40Ar/39Ar定年的影响。应用40Ar/38Ar-39Ar/38Ar等时线关系或39Ar/38Ar-36Ar/38Ar相关性进行36Ar修正有可能获得有意义的年龄值;修正后的阳起石年龄为235.7～238.6Ma,片沸石年龄为149.1Ma,可与无氯沸石的年龄相比较。
The natural copper mineralization associated with the northeastern Emeishan large igneous province is located between the Permian basalts in the Ludian, Maolin, and Qianxiang synclines and the overlying Xuanwei Formation. The mineralites related to natural copper mineralization, such as laponite (LD-14-3, YSD-1 and YC-1), all give consistent 40Ar / 39Ar plateau age and isochron age (226-228 Ma ). Such minerals do not interfere with Ca and Cl and are suitable 40Ar / 39Ar dating objects. However, their Ar closure temperature is lower, between 100 ~ 110 ℃. The resulting age represents the first metallogenic age. The 40Ar / 39Ar stable plateau age of (134.0 ± 1.7) Ma for sheet zeolite with an Ar closure temperature of less than 70 ° C and Cl-free intercalation was established and compared with the U-Th-Pb isochronal dating Which shows that there is a second low-temperature hydrothermal effect and natural copper mineralization in this area in the early Cretaceous. Therefore, the non-chlorine zeolite 40Ar / 39Ar dating can be widely used in low temperature metamorphism and cooling heat history. The influence of Cl interference on the dating of 40 Ar / 39 Ar exists in the samples of actinite and schist with high 38Ar content. It is possible to obtain meaningful age values by applying the 40Ar / 38Ar-39Ar / 38Ar isochronism or the 39Ar / 38Ar-36Ar / 38Ar correlation for the 36Ar corrections. The corrected age of the eruptive rock is 235.7-238.6Ma, 149.1Ma, comparable to the age of non-chronolite.