摘要
利用单颗粒锆石Ｕ－Ｐｂ法分别测定了桐庐和相山火山－侵入杂岩中早期及晚期形成的岩石单元的结晶年龄，桐庐杂岩体中早期火山岩的喷发年龄为１３４．９Ｍａ，晚期浅成岩的结晶年龄为１３４．４Ｍａ，杂岩体基本上属于同时形成，为早白垩世岩浆活动的产物；相山杂岩体中第二阶段岩石的结晶年龄为１４０．３Ｍａ，最晚阶段超浅成岩的结晶年龄为１３５．４Ｍａ，杂岩体各单元的形成时间相近，为晚侏罗世末期岩浆活动的产物。可见利用单颗粒锆石Ｕ－Ｐｂ年龄能非常有效地讨论一套岩石组合是否是同时间形成的，而这正是火山－侵入杂岩研究的重要内容之一。
The crystallization ages of both early and late stage rocks in the complexes of Tonglu and Xiangshan were determined by using the single grain zircon U Pb method, respectively. The single grain zircon U Pb isotopic age is 134 9 Ma for the first stage of volcanic rocks and 134 4 Ma for the latest stage of hypabyssal rocks in the Tonglu complex. It is show that the Tonglu complex was formed in the same time on the whole, and belongs to the products of early Cretaceous magmatism. In the Xiangshan complex, the early volcanic facies and the latest subvolcanic facies were formed at 140 3Ma and 135 4Ma, respectively. It is show that the Xiangshan complex was formed in the similar time, and belongs to the products of the late stage of late Jurassic magmatism. Therefore, the single grain zircon U Pb chronology is an effective method for discussing whether the rock units in complex are formed in the same time. This is one of the major study contents of volcanic intrusive complex.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
1999年第2期272-278,共7页
Acta Petrologica Sinica
基金
国家自然科学基金
关键词
火山-侵入杂岩
单颗粒锆石
铀-铅年龄
同时性
Volcanic intrusive complex, Single grain zircon U Pb isotopic age, Concordance in forming time, Tonglu, Xiangshan
