湖南东北部万古金矿区硫化物S-Pb-H-O同位素地球化学数据

2017年，将硫化物单矿物与氧化亚铜在真空状态下加热，进行氧化反应，生成二氧化硫，再用德国产Finnigan MAT-251气体同位素质谱仪分析硫同位素组成，其34S测定值的精确度好，相对误差为±0.2‰，相对标准为V-CDT。
将样品在溶解之前用Milli-Q水超声清洗。烘干以后称取约50 mg左右的样品，完全溶解在1:1的HNO3+HCl的混合酸中。然后蒸干样品，加入三次0.2 mL的2N HBr，分别蒸干。之后再次溶解在HRb+HNO3的混合酸中，两次通过50 μL的AG1X8（200～400目）阴离子交换树脂来分离纯化铅。然后将样品连同硅胶和磷酸一起点在Re单带上(Gerstenberger and Haase, 1997)。测试所用仪器为Isoprobe-T表面热电离质谱仪，分析精度为206Pb/204Pb为0.2%，207Pb/204Pb 为0.2%，208Pb/204Pb为0.5%。测试结果通过NBS981标样来校正分馏，标样的标准值据为206Pb/204Pb=16.937±0.002 (2σ)，207Pb/204Pb=15.457±0.002 (2σ)和208Pb/204Pb=36.611±0.004 (2σ)(Todt 等, 1996)。
石英的氧同位素分析采用传统的BrF5分析方法(Clayton and Mayeda, 1963)，用 BrF5与含氧矿物在真空和高温条件下反应提取矿物氧，在700℃与石墨棒反应转化成CO2气体，分析精度为±0.2‰，相对标准为V-SMOW。石英流体包裹体中 H 同位素分析采用Zn分解法。选取40 – 60目的纯净石英样品，在150℃低温下真空去气4小时以上，以彻底除去表面吸附水和次生包裹体水，然后在400℃高温下爆裂取水，并与金属锌反应生成H2，分析精度为±0.2‰，相对标准为V-SMOW。

In 2017, single sulfide minerals and cuprous oxide were heated under vacuum to undergo an oxidation reaction, generating sulfur dioxide. The sulfur isotope composition was then analyzed using a German-made Finnigan MAT-251 gas isotope mass spectrometer. The measured 34S values have high precision, with a relative error of ±0.2‰ and the relative standard being V-CDT.

Prior to dissolution, samples were ultrasonically cleaned with Milli-Q water. After drying, approximately 50 mg of sample was weighed and completely dissolved in a 1:1 (v/v) HNO3 + HCl mixed acid. The sample was then evaporated to dryness, and three 0.2 mL portions of 2N HBr were added followed by evaporation to dryness each time. The sample was redissolved in an HRb + HNO3 mixed acid, and lead was separated and purified twice using 50 μL of AG1X8 (200–400 mesh) anion exchange resin. Subsequently, the sample was loaded onto a Re single filament together with silica gel and phosphoric acid (Gerstenberger and Haase, 1997). The analysis was performed using an Isoprobe-T surface thermal ionization mass spectrometer, with analytical precisions of 0.2% for 206Pb/204Pb, 0.2% for 207Pb/204Pb, and 0.5% for 208Pb/204Pb. The test results were corrected for mass fractionation using the NBS981 standard reference material, whose certified values are 206Pb/204Pb = 16.937 ± 0.002 (2σ), 207Pb/204Pb = 15.457 ± 0.002 (2σ), and 208Pb/204Pb = 36.611 ± 0.004 (2σ) (Todt et al., 1996).

Oxygen isotope analysis of quartz was performed using the traditional BrF5 digestion method (Clayton and Mayeda, 1963). Mineral oxygen was extracted by reacting BrF5 with oxygen-bearing minerals under vacuum and high-temperature conditions, then converted to CO2 gas via reaction with graphite rods at 700℃, with an analytical precision of ±0.2‰ and the relative standard being V-SMOW. Hydrogen isotope analysis of quartz fluid inclusions adopted the Zn decomposition method. Pure quartz samples of 40–60 mesh were selected and subjected to vacuum outgassing at 150℃ for over 4 hours to thoroughly remove surface-adsorbed water and secondary inclusion water. Subsequently, water was extracted via crush-heating at 400℃, and reacted with metallic zinc to generate H2, with an analytical precision of ±0.2‰ and the relative standard being V-SMOW.