黔中地区震旦系喷流沉积磷矿再认识

Re-recognition of the Sinian Exhalative Sedimentary Phosphate Deposits in the Central Area of Guizhou Province

通过分析Rodinia超大陆演化与黔中地区磷矿的富集—贫化过程,重新认识磷质富集的成矿地质背景.黔中地区新元古代—早古生代经历了Rodidia超大陆演化伴随的多期海底火山喷发,是中小规模生物活动的缺氧、弱酸—还原性及低纬度海相环境的富磷过程,加快了生物发展演化,到580 Ma陡山沱晚期引发了以瓮安为主的多地生物爆发,较澄江生物爆发提前约50 Ma.磷矿有利成矿背景主要是在陡山沱期瓮安—开阳一带的台地边缘浅滩,后在灯影期向西迁移,以贵州织金新华磷矿和云南昆阳磷矿为代表.研究认为:从黔中地区到云南昆阳一带可能还隐伏大规模磷矿,具广阔的找矿远景.从织金新华磷矿中品位较高的重稀土和瓮福磷矿中幔源铅的存在,指示了沿织金—瓮安一带具备了新元古代—早古生代地层中可能还存在30%左右的大型—超大型喷流沉积及新矿种的找矿远景.

By analyzing the evolution of the Rodinia supercontinent and the process of phosphorous enrichment and depletion in central Guizhou,the metallogenic geological background of phosphorous enrichment was re-recognized.The Neoproterozoic-Early Paleozoic in central Guizhou experienced multi-stage submarine volcanic eruption accompanied by Rodidia supercontinent evolution,which was a process of anoxia,weak acid-reducibility of small-scale biological activities and phosphorus enrichment in low-latitude marine environment,which accelerated biological development and evolution.In the late Doushantuo period of 580 Ma,many biological outbreaks mainly occurred in Weng'an,which was about 50 Ma earlier than that in Chengjiang River.The favorable metallogenic background of phosphate rock was mainly in the platform margin shoal around Weng'an-Kaiyang in Doushantuo period,and then moved westward in Dengying period,represented by Zhijin Xinhua Phosphate Rock in Guizhou and Kunyang Phosphate Rock in Yunnan.It is concluded that there may be hidden large scale phosphate deposits from central Guizhou to Kunyang in Yunnan province,which have a wide range of prospects.The existence of high grade HREE in Xinhua phosphate deposit of Zhijin and mantle-derived lead in Wengfu phosphate deposit indicates that Neoproterozoic to Early Paleozoic strata in the area of Zhijin and Weng'an may also have 30%±large scale to super large scale jet deposition and prospect of new ore species.