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在野外地质观察基础上,运用光学显微镜、化学分析、X射线衍射、扫描电镜、流体包裹体成分分析等手段,对印尼塔里亚布锡铁多金属矿床中矿浆型磁铁矿的矿物学特征进行了研究。结果表明,矿浆型铁矿体界线清晰,呈贯入充填形态,围岩蚀变简单。矿石具块状条带、气孔状、流纹状、熔结瘤状等典型矿浆型铁矿石构造。矿石矿物组成简单,磁铁矿含量高,磷灰石+磁铁矿是标志性矿物组合。磁铁矿在化学成分上富铁(TFe=66.08%～68.01%)、富镁(MgO=3.05%～3.22%)、贫硅(SiO2=0.82%～1.91%)、贫碱(Na2O+K2O<1.06%),具明显铕负异常(δEu=0.14～0.55)。磁铁矿晶胞参数介于0.8390～0.8397 nm,接近标准值。磁铁矿晶体以致密它形晶为主,重结晶形成的三晶嵌连结构反映矿浆冷凝结晶是典型的退火过程。磁铁矿流体成分富集Li+(0.234μg/g)、Na+(3.438μg/g)等碱性阳离子及H2O(4129μg/g)、SO42-(8.916μg/g)及其它挥发性组分。在富碱、富挥发分和高氧逸度条件下,研究区矿浆型铁矿与花岗岩是酸性原始岩浆高度演化分异的同源产物。
Based on the field geological observation, the mineralogical characteristics of the pulp-type magnetite in the Tarim Yabu-tin iron polymetallic deposit, Indonesia were analyzed by optical microscopy, chemical analysis, X-ray diffraction, scanning electron microscopy and fluid inclusion composition analysis Were studied. The results show that the boundary of ore-bearing iron ore body is clear and in-fill filling form, and the wall rock alteration is simple. Ore with massive strip, stomatal, flow pattern, fused nodular iron ore and other typical structure. Ore mineral composition is simple, high magnetite content, apatite + magnetite is a landmark mineral combination. Magnetite is chemically rich in iron (TFe = 66.08% -68.01%), magnesium-rich (MgO = 3.05% -3.22%), silicon poor (SiO2 = 0.82% -1.91%), lean alkali (Na2O + K2O < 1.06%), with obvious negative anomalies of europium (δEu = 0.14 ~ 0.55). The magnetite cell parameters ranged from 0.8390 ~ 0.8397 nm, close to the standard value. The magnetite crystals are mainly dense crystals, and the three-crystal inlay structure formed by recrystallization reflects the crystallization of the slurry, which is a typical annealing process. Magnetite fluid components are enriched in basic cations such as Li + (0.234 μg / g), Na + (3.438 μg / g) and H2O (4129 μg / g), SO42- (8.916 μg / g) and other volatile components. Under the conditions of alkali-rich, volatile and high-oxygen fugacity, the ore-bearing iron ore and granite in the study area are the homologous products of highly evolved and differentiated acidic magma.