摘要:
概述 粤北地区为由上古生界所组成的两个互相连系的复向斜。北东部分是由前泥盆系组成的诸广山复背斜;西部有一条南北向半岛形的前泥盆系瑶山复背斜使本区与粤西北上古生界复向斜相隔;南部为前泥盆系的云开复背斜北东端。在雪山嶂一带分布成东西向排列的几个由前泥盆系组成的短轴背斜,使本区分隔成南北两部分。值得注意的是,粤北地区前泥盆地的构造线分布很奇特,北部为北北西,南部为北东东,两者互相垂直,其分界恰好位于本区南部的英德上古生界复向斜中。
Abstract:
The Middle-Late Devonian of northern Guangdong is mainly composed of sedimentary rocks of marine carbonate facies.The belt of carbonate facies of tidal flat is the most developed sedimentary facies in this region, it is mainly distributed in the sedimentary rocks in late Middle Devonian and early Late Devonian rocks of Le-chang and Renhua Counties.The belt includes laminated dolomite facies, allochem limestone facies, stromatolithic micrite facies, biocalcarenite facies, biolithite facies, coral reef facies and intraclastic limestone facies, etc.The belt of the partial barrier sea basin facies is found in Late Devonian deposits from Lechang and Renhua Counties to Shaoguan city. It is mainly composed of carbonaceous muddy biolithite facies, sulfide micrite facies and biomechanically disturbed micrite facies. The belt of open sea basin facies, which is a suit of rhythmite that consists of alternation of oncolite limestone facies,micrite facies with siliceous nodules and styliolinida micrite facies, occurs in the western region of Yaoshan anticlinorium in Middle-Late Devonian and in the area from Lechang to Shaoguan in Late Devonian. The belt of slope facies, being a suit of carbonate slumping sedimentary conglomerate, is distributed along the western margin of Yaoshan anticlinorium and the northern margin from Wudianmeihua anticlinorium to Yunkai oldland in early Late Devonian. The belt of trench facies is distributed in the area of Yingde County in Middle-Late Devonian. It is a formation of micrite containing some of tentaculitida, styliolinida and radiolaria with a bed of abyssal mudstone. Separated by the Yaoshan barrier islands and Xueshan barrier islands, the region from Lechang to Shaoguan has been developed into a barrier sea basin.To the western part of Yaoshan barrier islands is the Meihua open sea basin and between Xueshan barrier islands and Yunkai oldland is the Yingde trench.It is worth noticing that the E-W trend of Yingde trench lies exactly on the dividing lines between two tectonic systems of Pre-Devonian in northern Guangdong, which are mutual perpendicular-one being NNW, and the other NEE. So it can be inferred that the Yingde trench was developed on the basis of tectonic rift strap formed in Caledonian movement. The distribution of many pyrites and polymetal ore deposits along either side of Yingde trench shows that the rift strap may be an important zone of mineralization.
点击查看大图
下载:
