| 扬帆.昆阳磷矿沉积环境与矿床地球化学[J].地质与勘探,2011,47(2):294-303 |
| 昆阳磷矿沉积环境与矿床地球化学 |
| Sedimentary Environment and Geochemistry of the Kunyang PhosphoriteDeposit in Eastern Yunnan Province |
| 投稿时间：2009-06-09 修订日期：2010-07-12 |
| DOI： |
| 中文关键词: 昆阳磷矿沉积环境矿床地球化学 |
| 英文关键词: Kunyang phosphorite deposit, sedimentary environment, deposit geochemistry |
| 基金项目:中化地质矿山局资助项目(编号:2009-地-13),名称:中国磷矿床研究。 |
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| 中文摘要: |
| [摘要]滇东地区昆阳磷矿床是特征海相沉积大型磷矿床,位于扬子古地块西南缘,矿区内广泛
出露下寒武统筇竹寺组(缀1
3 q),为含磷岩系顶板岩系;中谊村组(缀1
2 z)含磷岩系和小歪头山组(缀1
1 x),含
磷岩系底板岩系;寒武系沉积基底为上震旦统灯影组(Zbdn),其间均具有冲刷面,显示含磷岩系出现在
地球变暖期,即海进旋回沉积早期。磷矿沉积岩中透镜状潮汐层理发育,并常见波痕和干裂构造,矿石
矿物为球粒状鲕状结构,显示为胶状沉积特征。矿石矿物成分主要非晶质胶磷矿,矿石组分及岩石化学
表明矿石组成主要有氟磷灰石矿物、碳酸盐矿物,主要高镁白云石和硅酸盐碎屑矿物。含磷岩系中稀土
及铀含量较高,磷矿石中稀土配分图显示明显的负铈异常,稀土富集与Fe2 O3 正相关,表示表层氧化沉
积环境。这些特征表明含磷岩系主要形成于滨海潮汐带,分为潮上-潮间和潮下浅海环境,因此主要是
稳定台缘或者浅水大陆架环境沉积。 |
| 英文摘要: |
| Abstract:The Kunyang phosphorite deposit in eastern Yunnan Province is a large-scale one characterized by marine sediments, tectonically located
at the southwestern margin of the ancient Yangtze block郾The Lower Cambrian Qiongzhusi Group (缀1 3 q) outcropping widely in the ore district constitutes
the roof rocks, which are also phosphor-bearing sedimentary formation郾The Zhongyicun group (缀1 2 z) containing phosphoric sedimentary formation and
Xiaowaitoushan Group (缀1 1 x) are the bottom of P-bearing sedimentary formation郾The Dengying Group (Zbdn) of Sinian System constitutes the Cambrian
sedimentary basement, within which erosion planes are present郾This indicates that the phosphoric rock formed at the early transgression cyclic deposition
during the global warming period郾Phosphorite sedimentary rock is characterized by well-developed lenticular tidal bedding, and ripple mark and desicca鄄
tion crack are very common郾Ore minerals occur as spherical oolite texture, showing the feature of colloform deposition郾Ore minerals are predominantly
comprised of amorphous collophanite郾Ore composition and lithochemical analysis show that the ore consists mainly of fluor-apatite and carbonatic minerals
such as high-Mg dolomite and silicatic detrial minerals郾P-bearing rock series is characterized by high content of rare earth elements and uranium, dis鄄
tinct negative Ce anomalies in REE distribution diagram of phosphorite ores, and positive relation between REE enrichment and Fe2 O3 , strongly sugges鄄
ting an environment of shallow oxidation deposition郾All these features indicate that P-bearing sedimentary formation formed mainly in a littoral area con鄄
taining supratidal, intertidal and subtidal shallow zones郾Therefore, the deposit formed mainly in a sedimentary environment of either stable platform mar鄄
gin or a shallow continental shelf郾 |
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