摘要
根据三条Pb-Pb等时线和三个锆石的U-Pb年龄,参考已有年代学数据,结合最新的区测成果,认为五台群内部不存在不整合,只经受一次构造-岩浆-变质作用。绿片岩和角闪岩是区域变质横向不均一造成的,它们之间为构造推覆接触。五台群上限年龄2500Ma,下限根据阜平群变质年龄推定约2800Ma。
Three Pb-Pb isochrons and zircon U-Pb ages, in conjunction with the published data and recent geologic observations provide evidence of no unconformities within the Wutai Group, although a tectonic-magmatic-metamorphic event is most likely to have occurred. Green schists and amphibolites were derived from regional metamorphism characterized by lateral heterogeneities. Their underthrust contact relations are evident. The upper age limit of the Wutai Group is estimated at 2.5 Ga, and the lower one at about 2.8 Ga as deduced from the age of the Fuping Group.
出处
《地球化学》
CAS
CSCD
北大核心
1991年第4期321-330,共10页
Geochimica
基金
自然科学基金委(4870186)
