摘要
佛坪片麻岩系是秦岭造山带核部所出露的众多古老块体之一，笔者利用锆石Ｕ－Ｐｂ法测得１８５３～２２８４Ｍａ年龄数据，是目前该区所获最老年龄资料，可能接近于其成岩时代。其地质意义在于：①证实佛坪片麻岩成岩时代为早元古代；②４２４±５Ｍａ、３００±１７Ｍａ和２１２．８土９．４Ｍａ的年龄信息表明加里东－印支期构造热事件对佛坪片麻岩有重大影响，③所获２１３．２～１４４７Ｍａ等大量表面年龄数据是片麻岩长期演化过程中多次地质作用综合后的混合年龄。
Foping gniess system is one of old geologic bodies exposed in the center of the Qinling orogenic belt. The U-Ph isotopic age of zircons is 1853-2 284 Ma, which is the oldest age of gniess system and approachs the protolith age. The age has thress significances as follows ① The protolith age verifies that gniess formed in early Proterozoic. ② The ages of 424 ±5 Ma, 300±17 Ma and 212. 8±9 Ma show that there was the influence of hot-tectoric cuents for the gniess during Caledonican-Indosinian. ③ The apparent age of 213. 2-1 447 Ma is mixed one of the gniess system and the effect of many geological functions.
出处
《西北地质科学》
1997年第2期21-25,共5页
Northwest Geoscience
