四川省昆阳式磷矿地质特征及成矿模式  

Geological characteristics and metallogenic model of phosphate deposit of Kunyang type in Sichuan Province

作　　者：贺天全 李斌斌 张春颖 HE Tianquan;LI Binbin;ZHANG Chunying(Sichuan Exploration Institute of Chemical Geology, Sichuan Chengdu 611930, China)

机构地区：[1]四川省化工地质勘查院,四川成都611930

出　　处：《中国地质调查》2022年第2期15-24,共10页Geological Survey of China

基　　金：中国地质调查局全国矿产资源评价“四川省矿产资源潜力评价(编号:1212010881629)”项目资助。

摘　　要：四川省昆阳式磷矿位于上扬子台拗峨眉山断拱和凉山陷褶束,属川滇早寒武世成磷带北段,磷矿赋存于下寒武统麦地坪组(C_(1)m)的中下部,层状延伸,其产状与含磷层一致,层位稳定,分布广,资源储量规模大,具有巨大的找矿潜力。在收集、整理前人研究资料和勘查项目成果的基础上,通过总结矿床地质特征及其矿床分布规律,分析成矿古构造、古地理环境等成矿地质条件及其成矿要素,建立了区域成矿模式。分析认为昆阳式磷矿成矿作用主要是生物-化学沉积作用,属离子化合沉淀和胶体聚沉-盆内成屑再积成因的海相磷块岩矿床;矿床的形成与分布均受古构造、古地理的控制,磷矿床主要富集于沿SN向古断裂形成的断陷盆地中次一级凹陷盆地内;成矿环境为海湾环境,具备从低能到高能的水动力条件,加之海湾内部的地貌分异,所形成的若干次一级小盆地,是成磷和聚磷的良好场所;开阔海湾丰富的磷质来源、中—高能环境的破碎、冲刷、簸选、搬运等机械作用以及适宜的凹陷小盆地沉积环境是形成富磷矿的有利条件;其成矿模式为生物-化学沉积—破碎、冲刷、簸选—搬运堆积成岩成矿。该成矿模式的建立为区内科学找矿提供了理论依据,为下一步找矿提供了方向。The phosphate deposit of Kunyang type in Sichuan Province is located in Emeishan fault arch and Liang-shan depression fold bundle of upper Yangtze platform depression,belonging to the northern part of the Early Cambrian.The occurrence of phosphate deposit is in the middle and lower part of Mediping Formation of Lower Cambrian and it extends in layers,similar with the phosphorus bearing layer.The phosphate deposit has characters of stable sequence,wide distribution and large reserves,with great prospecting potential.The authors in this paper summarized the geological characteristics of the deposit and the distribution regularity of the deposit to analyze the metallogenic geological conditions and metallogenic elements such as metallogenic paleostructure and palaeogeographic environment,and establish the regional metallogenic model,on the basis of collecting and sorting out previous research data and achievements of exploration projects.It is considered that the mineralization of phosphate deposit of Kunyang type is mainly biochemical sedimentation,which belongs to a marine phosphate rock deposit formed by ionic combined precipitation and debris accumulation in a basin.The formation and distribution of the deposit are controlled by paleogeography and paleostructure,and the phosphorus deposits are mainly concentrated in the secondary sagbasin of the faulted basin formed along the South north oriented paleofault.The bay environment has hydrodynamic conditions from low energy to high energy,and several sub primary small basins formed by the geomorphic differentiation inside the bay,which make the bay a good place for phosphorus formation and accumulation.The results show the favorable conditions for the formation of phosphorus rich deposit are the abundant phosphorus source,the mechanical effects of crushing,scouring,winnowing and transportation in the medium high energy environment,and the suitable sedimentary environment in the small depression basin.The metallogenic model is biochemical deposition,crushing,scouring

关 键 词：昆阳式磷矿 矿床地质特征 成矿地质条件 区域成矿模式 

分 类 号：P619.213[天文地球—矿床学]