鲁东地区侵入岩形成时代和期次划分——锆石SHRIMPU—Pb年龄的证据

鲁东地区前寒武纪侵入岩其侵入活动集中于新太古代和新元古代，均遭受不同程度的区域变质和韧性剪切带的改造，形成一套花岗质片麻岩类。新太古代早期TTG质花岗岩分布于胶北隆起区莱州一栖霞一带，经受了区域变质作用，形成一套灰色片麻岩，锆石内核SHRIMPU—Pb年龄2726—2707Ma基本代表岩浆结晶年龄，锆石变质边为2500Ma；古元古代侵入岩——莱州基性一超基性岩组合形成于1900～1850Ma左右，锆石SHRIMPU—Pb年龄（1852±9）Ma，（1868±11）Ma；新元古代侵入岩主要为花岗闪长质-二长花岗质片麻岩，出露于胶南-威海造山带，锆石U～Pb定年结果集中为892～605Ma，其中荣成超单元锆石SHRIMPU—Pb年龄720～780Ma。中生代侵入岩以花岗岩类为主，集中出露于半岛北部和东南沿海一带。燕山早期侵入岩文登超单元、垛崮山超单元、玲珑超单元锆石SHRIMPU—Pb同位素年龄值集中在167～150Ma；燕山晚期侵入岩大店超单元锆石SHRIMPU～Pb年龄120±4Ma，崂山超单元锆石SHRIMPU～Pb同位素年龄值为（120±2）～（114±2）Ma。

Study on Intrusive Rocks Forming Period and Stages Division in Ludong Area

Intrusive activities of early Precambrian intrusive rocks in Ludong area focused on new Archean and Proterozoic are all sufferred different degrees of regional metamorphism and ductile shear zone, and formed a series of granitic gneiss. TTG granitoids of new early Archean distributed in Laizhou - Qixia area of Jiaobei uplift, and experienced regional metamorphism and formed a set of gray gneiss. SHRIMP U - Pb age of zircon core is 2726 2707Ma, which basically represent magmatic crystallization age. The zircon metamorphic side is 2500Ma; Paleo- proterozoic intrusive rocks, that is Laizhou basic -ultrabasic rock combination were formed in about 1900 1850Ma. Its zircon SHRIMP U -Pb age is （1852 ±9）Ma, （1868 ± 11） Ma; Neoproterozoic intrusive rocks are mainly composed of granodioritic- monzonitic granitic gneiss, and exposed in Jiaonan -Weihai orogenic belt. Its zircon U - Pb dating results focus on 892 - 605 Ma. Mesozoic intrusive rocks are mainly composed of granitoid, and concentrated exposed in north part ofthe peninsula and southeast along the coast. Zircon SHRIMP U - Pb isotopic ages of intrusive rocks in early Yanshan period, such as Wendeng superunit, Duogushan superunit and Linglong superunit are 167 - 150Ma; while zircon SHRIMP U - Pb isotopic ages of Laoshan superunit in Yanshan intrusive rocks is （119.8 ±2.5） - （114.3 ± 1.9）Ma.