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根据湘南高温地热区硼同位素研究 ,总结了硼同位素的分馏特征。湘南高温热液交代矿床硼酸盐矿物的δ11B值均为负值 (- 1.34‰～ - 13.2 8‰ ) ;不同蒸馏阶段获得样品的δ11B值有较大差异 ,早期蒸馏硼酸较晚期蒸馏硼酸有较高的δ11B值 ,晚期蒸发阶段样品的δ11B值较早期阶段的δ11B值低近 4 0 % ,表明在热液交代过程中11B较10 B活跃 ,优先进入流体相或蒸汽相 ;水岩作用中硼同位素分馏与硅化交代强度成正相关关系 ,并且是硅置换11B ,造成岩石亏损11B ,而呈现低的δ11B值 ;水化反应中硼被吸入 ,并优先吸入11B ,导致蚀变岩中δ11B升高。研究认为 ,硼同位素分馏特征可以用于分析成矿流体演化及水岩作用性质 ,而不限于分析成矿物质来源。
According to the boron isotope study in high temperature geothermal area in southern Hunan, the fractional boron isotope fractionation characteristics are summarized. The δ11B values of borate minerals in the high-temperature hydrothermal replacement ore deposits in the southern Hunan are all negative (- 1.34 ‰ ~ -13.2 8 ‰). The δ11B values of the samples obtained in different distillation stages are quite different. The δ11B value of the late evaporating stage was 40% lower than the δ11B value of the early stage, indicating that 11B was more active than 10 B in hydrothermal stage and preferentially entered the fluid or vapor phase. Isotope fractionation was positively correlated with the silicification metasomatism intensity, and was replaced by silicon 11B, resulting in a rock loss 11B, but a low δ11B value. During the hydration reaction, boron was inhaled and 11B was preferentially inhaled, resulting in δ11B elevation in altered rocks. It is believed that boron isotopic fractionation can be used to analyze the evolution of ore-forming fluid and the nature of water-rock interaction, and not limited to the analysis of ore-forming material sources.