地质通报2011，Vol.30Issue(5)：798-802,5.
北京密云元古宙常州沟组之下环斑花岗岩古风化壳岩石的发现及其碎屑锆石年龄
Discovery of the paleo-weathered mantle of the rapakivi granite covered by the Proterozoic Changzhougou Formation in the Miyun area,Beijing and their detrital zircon dating
摘要
Abstract
Recently, the Proterozoic rapakivi granites (dike) with the paleo-weathered mantle-clastic rocks covered directly by the sandstones of the Changzhougou Formation of Changchengian System are discovered in the Miyun County, Beijing. The detrital components of the rocks embrace the in-situ weathered mantle saprolites and coarse-grained clastic rocks from rapakivi granites.Through SHRIMP and LA-ICP-MS dating methods, we have obtained the U-Pb dating ages of 1682±20 Ma and 1708±6 Ma from the detrital zircons sampled in the rocks; those age data are the same with the nearby Miyun rapakivi granite. The existence of this suite of weathered saprolites and clastic rocks, as well as the analysis of the dating results, have shown that the age of the base of the Changzhougou Formation should be younger than 1682 Ma.关键词
古风化壳岩石/环斑花岗岩/碎屑锆石SHRIMP和LA-ICP-MS测年/长城系常州沟组/中元古界/北京Key words
paleo-weathering mantle rocks/ rapakivi granite/ detrital zircon SHRIMP and LA-1CP-MS dating/ Changzhougou Formation of Changchengian System/ Mesoproterozoic/ Beijing分类
天文与地球科学引用本文复制引用
和政军,牛宝贵,张新元,赵磊,刘仁燕..北京密云元古宙常州沟组之下环斑花岗岩古风化壳岩石的发现及其碎屑锆石年龄[J].地质通报,2011,30(5):798-802,5.基金项目
国家自然科学基会项目《冀西北尚义盆地的晚侏罗世同构造沉积响应》(批准号:40872081)和中国地质调查局项目《亚洲三大构造域动力演化过程及其转化关系研究》(编号:1212010611808)、《兴蒙造山带基本构造格局综合调查和研究》(编号:1212011085476) （批准号:40872081）
