摘要
滇东南地区的下石炭统,以往只知有台地相碳酸盐沉积;本文报道的是以硅质岩为主,夹碳酸盐岩和火山岩,富含牙形石、放射虫、海绵骨针等,暂称之为坝达组(C_1b)。坝达组所含牙形石均为下石炭统重要化石分子,可与滇西北宁蒗地区对比,甚至可远与西欧、北美对比。坝达组应属台地相区较深水的台盆(沟)相带沉积,在沉积的中期至后期,逐渐向较浅水台地环境演变;而在整个沉积过程中,伴随地壳的张裂,曾有过多次火山喷发。
The Lower Carboniferous Series in SE Yunnan region has only been con-sidered as the carbonate sediments of platform facies before. According to the geological surveying results, it is composed mainly of silicalite intercalated with carbonate rock and volcanic rock, containing rich fossils of conodont, Radiolaria and bone needle in Demospongia, this paper temporarily terms the said rock formation“Bada Formation”(C_1 b). The conodonts contained in this Formation all belong to the important member of the Lower Carboniferous and can compard with the fossils found in the Ninglang area of NW Yunnan, even with the findigs in Western Europe and North America. The Bada Formation should be formed in the facies belt of deeper-sea platform basin(valley)in plat form facies tract and gradually evolved towards the more shallow-sea sediments during the middle to late stage. Accompanied by the crustal tension fracture, many times volcanic eruption happened in the whole sedimentary process.
出处
《云南地质》
1990年第4期313-320,共8页
Yunnan Geology
