四川雷波矿集区磷矿沉积特征及成矿规律研究

四川雷波地区磷矿属于中国昆阳式海相沉积型磷矿,赋存于下寒武统梅树村阶麦地坪组地层中。通过野外实测剖面,重点研究其岩石学和沉积相特征,在矿集区建立了潮坪沉积体系,判断麦地坪组以潮下带沉积为主,潮间带和潮上带沉积不发育,总体表现为海侵-海退-海侵的垂向沉积组合。沉积相在矿集区呈环带状分布,磷矿层厚度与地层厚度大体呈正相关关系。磷矿床的岩相古地理类型直接影响了磷质颗粒的物理富集过程,其中潮下高能带为磷矿沉积的最有利相带,是今后勘探开发的重点区域。

Sedimentary characteristics and mineralization of the phosphorite deposits in the Leibo ore field, Sichuan

The phosphorite deposits in the Leibo ore field, Sichuan are interpreted to be the Kunyang-type marine sedimentary phosphorite deposits, and hosted to the strata of the Lower Cambrian (early Meishucunian) Maidiping Formation. The integration of lithology and sedimentary facies analysis of the Maidiping Formation shows that the Leibo ore field roughly represents the vertical transgression-regression-transgression sedimentary associations in the carbonate tidal-flat sedimentary environment during the early Meishucunian. The sedimentary facies display zonal distribution, and there is a nearly positive correlation between the thickness of the phosphorite beds and those of the strata. The sedimentary facies distribution and palaeogeographic environments also have an important effect on the physical enrichment and mineralization of phosphorous particles. The subtidal high-energy zone is believed to be the most favourable zone for the accumulation and mineralization of phosphorite ores, and thus may be delineated as the key zone for future exploration of phosphorite deposits in the Leibo ore field.