云南拖顶泥盆纪岩相古地理及层序地层分析

Devonian sedimenatry facies and palaeogeography and sequence stratigraphy of the Tuoding copper mining district, Yunnan

关键词:  泥盆纪  岩相古地理  层序地层  拖顶铜矿

Key words:  Devonian  sedimentary facies and palaeogeography  sequence stratigraphy  Tuoding copper deposit

摘要:

云南拖顶一带的泥盆纪地层,由于受构造的的影响呈断块产出。通过对矿区泥盆纪地层的详细研究,认为其地层层序较为清楚,可以分出下泥盆统碎屑岩、中泥盆统碳酸盐岩和上泥盆统碎屑岩.碳酸盐岩。在详细的野外实地考察和室内研究的基础上,本文详细厘定了泥盆纪的沉积相,并恢复了岩相古地理格局。进而建立了该区的层序地层格架,分为5个沉积层序,并对沉积体系域与拖顶铜矿的关系进行了探讨。

Abstract:

The Devonian strata in the Tuoding region, Yunnan are widespread as fault blocks along the Jinsha River, especially on the eastern bank of the river. These strata may be composed of the Lower Devonian clastic rocks, Middle Devonian carbonate rocks and Upper Devonian clastic-carbonate rocks, and fall, according to sedimentary structures and lithology, into six distinct sedimentary facies:littoral, shallow sea and shelf, restricted platform, lagoon, biohermal and tidal-flat facies. There are gradations of the sediment configuration in the study area from the clastic shelf in the early stage to the carbonate platform sediments in the middle and finally to the mixed clastic-carbonate shelf in the late stage, indicating that the carbonate platform in this area was developed on a early clastic ramp. Five sedimentary sequences have been distinguished for the Devonian strata in the study area. The results of research in this paper have revealed that the copper mineralization occur in the highstand systems tract including the platform-bank laminated dolostone, dolarenite, pelleted dolostone and oncolite-oolitic dolostone.