A new type of polyhalite potassium ore(NTPPO) was found in the Lower Triassic Jialingjiang Formation, NE Sichuan Basin, SW China. It is water soluble, therefore can be exploited using the water-solution method, and is...A new type of polyhalite potassium ore(NTPPO) was found in the Lower Triassic Jialingjiang Formation, NE Sichuan Basin, SW China. It is water soluble, therefore can be exploited using the water-solution method, and is of great potential of economic value and research significance. Based on cores, thin sections, energy spectrum and SEM analyses, its microfeatures, macrofeatures and origin are discussed, and a genetic model is established to provide a scientific basis for future evaluation, prediction and exploration of potassium ore in the Sichuan Basin. It is proposed that the NTPPO was caused by storm activities:(1) the storm broke the original sedimentary polyhalite–gypsum beds, whose fragments were transported into the salt basin with high content of K+ and Mg2+;(2) in the basin, the polyhalite continued to be formed from gypsum by metasomatism with K-and Mg-rich brine;(3) during diagenesis, under high temperature and high pressure, K–Mg-rich brine from halite continued to replace anhydrite(or gypsum) to form polyhalite.展开更多
基金This study was performed under the China Geological Survey(Grant no.DD20190172)the Sino Probe(Grant no.2017YFC0602806)。
文摘A new type of polyhalite potassium ore(NTPPO) was found in the Lower Triassic Jialingjiang Formation, NE Sichuan Basin, SW China. It is water soluble, therefore can be exploited using the water-solution method, and is of great potential of economic value and research significance. Based on cores, thin sections, energy spectrum and SEM analyses, its microfeatures, macrofeatures and origin are discussed, and a genetic model is established to provide a scientific basis for future evaluation, prediction and exploration of potassium ore in the Sichuan Basin. It is proposed that the NTPPO was caused by storm activities:(1) the storm broke the original sedimentary polyhalite–gypsum beds, whose fragments were transported into the salt basin with high content of K+ and Mg2+;(2) in the basin, the polyhalite continued to be formed from gypsum by metasomatism with K-and Mg-rich brine;(3) during diagenesis, under high temperature and high pressure, K–Mg-rich brine from halite continued to replace anhydrite(or gypsum) to form polyhalite.
文摘烃源岩评价在油气成藏和资源潜力研究中均起着关键性作用,烃源岩地球物理预测能够有效地定量评价烃源岩.普光地区因可用钻井较少,难以对陆相须家河组烃源岩总有机碳质量分数（TOC）和厚度进行定量评价.文中基于烃源岩TOC体定量预测技术资料,对普光地区须家河组烃源岩的TOC和厚度进行地球物理预测.研究结果表明：须家河组主要为中等烃源岩,TOC值大多为0.60％～ 1.50％,与实测TOC数据比较吻合;烃源岩总有机碳主要以条带状分布,且成层性特征比较明显;须三、须五段的烃源岩在普光东南部及西北部等局部地区的TOC比较高,为好的烃源岩;须三段的有效烃源岩厚度主要为20～30 m,须五段主要为30～40 m.
