| 米云川.云南镇雄地区新发现羊场超大型磷矿沉积环境及资源潜力分析[J].地质与勘探,2021,57(4):808-824 |
| 云南镇雄地区新发现羊场超大型磷矿沉积环境及资源潜力分析 |
| The sedimentary environment and resource potential of the newly discovered Yangchang super-large phosphate deposit in the Zhenxiong area, Yunnan |
| 投稿时间：2020-12-08 修订日期：2021-06-08 |
| DOI：10.12134/j.dzykt.2021.04.008 |
| 中文关键词: 沉积环境 资源潜力 梅树村组 羊场背斜 磷块岩矿床 羊场磷矿 镇雄地区 云南 |
| 英文关键词: sedimentary envoironment,resource potential,Meishucun Formation, Yangchang anticline, phosphorus deposit, Yangchang phosphorus deposit, Zhenxiong, Yunnan |
| 基金项目:中国地质调查局项目(编号：12120113052600)和云南省地质勘查基金项目(编号：D201707、D202001)联合资助 |
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| 中文摘要: |
| 云南镇雄羊场磷矿是近年来新发现的超大型磷矿床，隐伏于羊场背斜核部。本文对羊场磷矿的矿床地质特征、成矿背景、沉积环境与沉积相、矿体特征及空间分布等进行了研究，认为矿床形成于早寒武世梅树村期，矿体赋存于梅树村组碳酸盐岩含磷岩系中；沉积环境为浅海碳酸盐台地干热潮坪环境（潮间-潮下带），沉积相为潮间-潮下间歇高能富白云岩、磷块岩相，由北西往南东海水逐渐变深，矿化变弱，矿体总体从聚磷盆地中心向周边有变薄趋势；矿床类型为海相沉积型层状磷块岩矿床。矿床形成过程为上升的海流把富磷的海水带到浅海地带时，由于温度升高和压力降低，使磷以磷酸钙的形式沉积于浅海地带的边缘上，形成规模巨大的磷矿；另外，沉积环境的旋回性变化伴随着生物、化学和物理作用对磷的溶解、迁移、富集和叠加改造再沉积的反复进行，致使磷矿层聚集存在多期和多层结构，矿层变厚矿石品位变富；在成矿后矿体受羊场背斜的叠加改造，使磷矿层再次变富变厚，矿床规模进一步变大。在钻探验证基础上，分Ⅰ、Ⅱ、Ⅲ品级圈定了工业磷矿体，并系统估算了羊场磷矿全区控制+推断磷矿石资源量；同时采用综合地质要素法、三维空间定位模型预测法分标高段预测了磷矿石潜在资源，认为羊场地区有望成为世界级磷矿资源基地。通过地层对比和沉积环境特征分析，认为羊场背斜东约20.0 km的芒部背斜，为寻找隐伏磷矿的另一有利地段。 |
| 英文摘要: |
| The super-large Yangchang phosphate deposit is newly discovered in the Zhenxiong area, Yunnan province, which is concealed at the core of the Yangchang anticline. This paper presents a study on the geological characteristics, metallogenic setting, sedimentary environment and sedimentary facies, ore body characteristics and spatial distribution of the Yangchang phosphate deposit. The deposit is hosted by the Meishucun Formation of Early Cambrian, belonging to the marine sedimentary stratified phosphoric type. Its sedimentary environment was a shallow sea carbonate platform featured by a dry upsurge flat setting (intertidal to subtidal zone). The sedimentary facies was dolomite and phosphorite formed in a high energy background between intertidal and subtidal zones. The large-scaled ore bodies show a trend to be thinned from the center to the periphery because of sea water gradually deepened from northwest to south. The phosphorus element deposited in the form of calcium phosphate at the margin of the shallow sea zone with decreasing pressure and increasing temperature during the process of rising currents carried phosphorus-rich water to shallow sea. The changed cyclicity of sedimentary environment was always accompanied by a series of biological, chemical, and physical processes, which could affect the dissolution, migration, enrichment and redeposition of phosphorus. These processes led to the multilayered structure of the ores in the multiple phase deposition. Based on data of boreholes, this work draws the pattern of industrial phosphorite ores in three classes of grade, estimates the amount of controlled and inferred phosphate ore resources and predicts the potential resources by means of the geological element method and the three-dimensional space positioning model in Yangchang. The deposit is expected to become a world-class phosphorus resource base. Analysis of stratigraphic correlation and the sedimentary environment suggests that the Mangbu anticline 20 km east to the Yangchang anticline is a potential target for the prospecting of concealed phosphorus ores. |
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