摘要
中石炭统金厂组（Ｃ２ｊ） 下部含金硅质岩是云南墨江金矿床的主要围岩之一，具有沉积结构构造，含热水沉积矿物。岩石的ＦｅＯ、Ｆｅ２Ｏ３ 、Ａｕ 和Ａｇ 含量高； Ｃｒ 、Ｎｉ 和Ｃｏ 含量高、变化大；ＭｎＯ／ＴｉＯ２ 和ＴＦｅ／ ＴｉＯ２ 比值较大； Ａｕ 含量与Ｎｉ、Ｃｒ 含量相关性低，Ａｕ 可能不是后期热液作用带入的。在判别硅质岩形成作用的一系列主元素和微量元素关系图上， 含金硅质岩位于热水沉积作用的范围内或接近于热水沉积作用。岩石的稀土元素和Ｏ、Ｓｉ 同位素组成表明含金硅质岩由热水沉积作用形成。成岩后的热液作用使含金硅质岩的地球化学特征偏离而不是增强了热水沉积作用的特征， 地质、地球化学特征表明含金硅质岩由热水沉积作用形成。
The auriferous cherts in the middle Carboniferous Jinchang formation are one of the dominant host rocks of the auriferous quartz veins and mixed ore bodies comprised of gold bearing quartz veins and cherts in Mojiang gold mine. The rocks are of sedimentary structure and composed of hot water deposited minerals.The content of FeO, Fe2O3, Au and Ag in the auriferous cherts are great;that of Cr, Ni and Co contents are great and very variable, MnO/TiO2 and TFe/TiO2 ratios are relatively high. On a number of diagrams which distinguish different chert formation, the auriferous cherts are among or near to the range of hot water deposited cherts.Since the correlation between Au content and Cr, Ni of the rocks is very bad, the high Au content in the cherts may be not brought about by the late hydrothermal fluid. The REE, O and Si isotope composition of the auriferous cherts demonstrates that the cherts belong to hot water deposited rocks. The later hydrothermal alteration makes the petrochemical compositions of cherts away from hot water deposition, not adding the characteristics. In general, the geological and geochemical features of the auriferous cherts demonstrate that the rocks formed by hot water deposition.
出处
《地球化学》
CAS
CSCD
北大核心
1999年第4期307-317,共11页
Geochimica
基金
中国科学院"八五"
"九五"重大科研项目!(编号:KY8512
KZA1404)
关键词
含金
硅质岩
热水沉积作用
金矿床
云南
chert, hot water deposition, gold deposit, Yunnan Province
