内蒙古大青山北前壕石英闪长岩锆石U-Pb年龄及地质意义  

Zircon U-Pb age of the quartz diorite in North Daqing mountains, central Inner Mongolia

作　　者：张玉清[1] 刘俊杰[1] 

机构地区：[1]内蒙古自治区地质调查院,呼和浩特010020

出　　处：《华南地质与矿产》2004年第4期22-27,共6页Geology and Mineral Resources of South China

基　　金：中国地质调查局1:5万区域地质调查项目(20001300008031).

摘　　要：前壕石英闪长岩侵入到新太古界色尔腾山岩群中,它们与斜长花岗岩等共同构成了新太古代花岗岩—绿岩带,石英闪长岩岩石化学、地球化学显示为I型花岗岩系,与太古宙高铝型TTG花岗岩系特征一致,为不同源岩部分熔融的产物(可能有幔源岩浆参与)。选自石英闪长岩中的锆石具岩浆型锆石的特点,5个单颗粒锆石U-Pb同位素年龄不一致曲线上交点年龄(2535±16)Ma,代表了该岩体的结晶年龄。结合色尔腾山岩群的年龄分析,大青山地区花岗岩-绿岩带形成于2500～2900Ma之间。该年龄的确定为华北陆台(或华北克拉通)的地壳演化提供了新证据。The Qianhao quartz diorites emplaced in Late Archean Se'ertengshan Group composes a part of the Late Archean granite-greenstone belt with plagiogranites. Petrochemical and geochemical research of quartz diorites shows the features I-type granites and accord with Archean high-aluminum TTG granites. They might be resulted through partial melting of different source rocks with participation of mantle magma. Five zircons selected from quartz diorites were crystallized from magma and constitute a U-Pb upper intersection age of (2535±16) Ma,which represents the crystalline age of the intrusion and providing new evidence for crustal evolution of North China Craton.

关 键 词：石英闪长岩 锆石U—Pb年龄 新太古代 花岗岩一绿岩带 大青山 内蒙 

分 类 号：P588.122[天文地球—岩石学] P597.3[天文地球—地质学]