浙北富阳神功村二长花岗斑岩脉SHRIMP锆石U-Pb年龄及其地质意义

Zircon SHRIMP U-Pb dating of monzogranite-porphyry dikes in Shengongcun, northern Zhejiang, and its geological implications

浙北富阳神功村地区二长花岗斑岩脉侵入于中新元古界地层中,采自该岩脉样品的锆石离子探针(SHRIMP)U-Pb同位素年龄为117.7Ma±2.7Ma。这一数据表明本区二长花岗斑岩岩脉的形成年代为早白垩世中期,而不是1∶5万填图资料所认为的新元古代时期(晋宁晚期)。新获得的高精度年龄数据支持华南中生代末广泛的岩浆侵入作用始于早白垩世中期的观点。

The Mesoproterozoic and Neoproterozoic strata in the Shengongcun area, Fuyang, northern Zhejiang, are intruded by a monzogranite-porphyry dike. Samples taken from the dike have high-resolution zircon SHRIMP U-Pb ages of 117.7±2.7 Ma. The data indicate that the monzogranite-porphyry dike was formed in the middle Early Cretaceous rather than in the late Jinninian stage in the early Neoproterozoic, as suggested by the data obtained by the 1∶50000 geological mapping. New high-precision age data also support the view that the terminal Mesozoic extensive magmatic intrusion in eastern South China began in the middle Early Cretaceous.