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用SHRIMP U-Pb和Sm-Nd定年技术,对攀西红格矿区含矿层状辉长岩、碱性正长岩进行了年龄测定。获得红格辉长岩中3种不同晶形锆石的U-Pb年龄分别为258.4±4.1Ma、1841±34Ma、2487±12Ma,由辉长岩、辉石和磷灰石所构成的Sm-Nd等时线年龄为253±14Ma;碱性正长岩中锆石的U-Pb年龄为257.2±1.5Ma。结果表明,红格辉长岩中具有典型基性岩锆石特征的锆石U-Pb年龄(258Ma)与同一地质样品的Sm-Nd年龄(全岩+矿物内部等时线年龄),以及同一矿区的正长岩锆石U-Pb年龄在测定误差范围内一致。鉴于层状辉长岩和碱性正长岩在空间上密切共生,在形成时间上一致,可以认为它们都属于晚二叠世末岩浆活动的产物;而1841Ma和2487Ma的锆石,可能是在基性-超基性岩浆的上侵过程中,从基底所捕获的岩浆锆石和继承锆石,其年龄信息,揭示了康滇地轴岩浆岩带的下部或结晶基底存在元古代甚至新太古代末期的岩石或物质。
SHRIMP U-Pb and Sm-Nd dating techniques were used to determine the ages of ore-bearing gabbro and alkaline syenite in Panxihongge Mining Area. The U-Pb ages of the three types of zircons from the Hongge gabbro are 258.4 ± 4.1Ma, 1841 ± 34Ma and 2487 ± 12Ma, respectively, and the Sm-Nd etc. composed of gabbro, pyroxene and apatite The line age is 253 ± 14Ma. The U-Pb age of zircons in alkaline syenite is 257.2 ± 1.5Ma. The results show that the zircon U-Pb ages (258 Ma) with typical basic zircons and the Sm-Nd ages (all-rock internal mineral isochron age) of the same geological samples in the Hongge gabbro and the same U-Pb ages of the syenite zircons in the mining area are consistent within the measurement error range. In view of the close spatial symbiosis of layered gabbro and alkaline syenite and their consistent timing of formation, they are all considered to be the product of Late Permian magmatism; however, the zircons of 1841Ma and 2487Ma may be at During the uplifting of the basic-ultramafic magma, the magmatic zircons and inherited zircons captured from the basement and their age information reveal that the Proterozoic or even Late Neo-Archaean Rock or substance.