【摘要】 蚌埠地区广泛出露早前寒武纪变质基底,包括新太古代-古元古代五河岩群、凤阳群以及少量的钾长花岗(片麻)岩。五河岩群上、下亚群的形成时间、沉积时限等问题一直存在争议。本文通过对五河岩群上亚群殷家涧岩组内变晶屑凝灰岩夹层进行锆石U-Pb年代学研究,获得成岩年龄为2140±17 Ma,表明五河岩群上亚群形成于古元古代中期。结合区域年代学研究成果,认为在蚌埠地区存在～2.1Ga的构造-岩浆-热事件。更多还原

【Abstract】 Early Precambrian metamorphic basement, including the Neoarchean-Paleoproterozoic Wuhe Group Complex, Fengyang Group and a small amount of potassium feldspar granite(gneiss), is widely outcropped in the Bengbu area.The formation time and sedimentation timeframe of the upper and lower subgroups of the Wuhe Group Complex have always been controversial. In this paper, zircon U-Pb chronology study on the interlayer of metacrystalline tuff in the Yinjiajian Formation Complex of the upper subgroup of the Wuhe Group Complex indicates that the diagenetic age of metacrystalline tuff is 2140±17 Ma, implying that the upper subgroup of the Wuhe Group Complex was formed in the middle Paleoproterozoic era. Combined with the research results of regional chronology, it is concluded that there is a tectonic and thermal event of ～ 2.1 Ga in the Bengbu area.更多还原