【摘要】 阳储岭斑岩型W-Mo矿床位于江南造山带中部，是华南地区最早发现的斑岩型钨钼矿床。已探明WO₃资源储量6.13万吨（平均品位0.2%）,Mo资源储量1.69万吨（平均品位0.03%～0.06%）,其成矿作用与中生代花岗质岩浆活动密切相关。区内发育早期花岗闪长岩和晚期二长花岗斑岩，钨矿体以细脉状和浸染状产于二长花岗斑岩体内，而花岗闪长岩内未见矿化。两期岩浆活动与钨成矿的关系尚不明确，制约其含矿差异性的因素尚不清楚。本文以花岗闪长岩和二长花岗斑岩中的黑云母为研究对象，对比研究两类岩浆结晶分异程度、氧逸度、岩浆流体卤素浓度，探讨其对钨成矿的制约。黑云母主量元素分析结果显示，阳储岭两类岩浆岩均为壳源，但显著不同于S型花岗岩的Mg/（Fe+Mg）和Al^VI值，指示其具有I型花岗岩的特征。黑云母的微量元素信息显示，相对于花岗闪长岩中的黑云母（类型一）,二长花岗斑岩中的黑云母（类型二）显示低的K/Rb、Nb/Ta比值，高的Rb、Cs、Nb和Ta含量，表明其分异程度较花岗闪长岩更高，更有利于钨的富集。两类黑云母所指示的岩浆氧逸度均在NNO缓冲线附近，表明其母岩浆均为还原性岩浆，但二长花岗斑岩显示出更为还原的特征，还原环境有利于钨矿的形成。类型二黑云母比类型一黑云母具有低的IV（F）但高的IV（F/Cl）值，表明其F富集程度更高。通过黑云母计算出对应岩浆流体的log（fH₂O/fHF）^fluid、log（fH₂O/fHCl）^fluid、log（fHF/fHCl）^fluid值。结果表明类型二具有比类型一更低的log（fH₂O/fHF）^fluid、log（fH₂O/fHCl）^fluid值，显示二长花岗斑岩流体中更加富含HF和HCl。而类型二高的log（fHF/fHCl）^fluid值，显示出其更高的HF/HCl比值，对应了更高的结晶分异程度。阳储岭晚期二长花岗斑岩与早期花岗闪长岩为同一岩浆房分离结晶作用的产物，矿化存在于二长花岗斑岩顶部，岩浆结晶分异过程中，挥发性组分F、Cl和成矿元素W、Mo从体积更大的花岗闪长质岩浆聚集到小体积的二长花岗质岩浆中，形成具有经济价值的W-Mo矿体。研究结果表明，黑云母可有效示踪花岗质岩浆性质和岩浆结晶分异程度，并可作为矿产勘查的有利标志。更多还原

【Abstract】 The Yangchuling porphyry W-Mo deposit is located in the middle part of the Jiangnan orogenic belt, which is recognized as the first typical porphyry type W-Mo deposit in South china. Reporting 63100 t of WO₃ with an average grade of 0.2% and 16900 t of Mo metal with a grade range of 0.03%～0.06%. The W-Mo mineralization is closely related to the Mesozoic granitic magmatism. Disseminated W mineralization is intimately associated with the late-stage monzogranite porphyry whereas the early-stage granodiorite is barren, it remains obscure as to the relationship between two types of magmatic rocks and what control their contrasting ore-forming potential. In this study, we compared the major and trace elements of biotites from the monzogranite porphyry and granodiorite, respectively, to explore their geochemical differences in magma differentiation, oxygen fugacity and halegon fugacity that may affect their mineralization potential. Major elements compositions of biotites in Yangchuling show that both granodiorite and monzogranite porphyry are derived from crust material, significant different Mg/（Fe+Mg） ratio and Al^VI values from the biotite in S-type granite worldwide indicating they are I-type granite. Trace elements of biotite can used to evaluate the differentiation degree of magma. The lower K/Rb, Nb/Ta ratios and higher Rb, Cs, Nb and Ta contents in biotite from monzogranite porphyry relative to biotite in granodiorite indicate higher differentiation degree of monzogranite porphyry, which is conducive to the enrichment of W. Both of magma lies near the NNO buffer line, but monzogranite porphyry shows more reducing characteristics, and the reducing conditions are conducive to mineralization. The biotite（type 2） in the monzongranite porphyry has a lower IV（F） and a higher IV（F/Cl） value indicating higher F enrichment relative to biotite（type 1） in the granodiorite, The halogen fugacity log（fH₂O/fHF）^fluid, log（fH₂O/fHCl）^fluid, log（fHF/fHCl）^fluid of associated magmatic fluid calculated by biotite show type 2 has a lower log（fH₂O/fHF）^fluid and log（fH₂O/fHCl）^fluid than type 1, suggesting monzogranite porphyry is richer in HF and HCl. Higher log（fHF/fHCl）^fluid in type 2 reflecting higher HF/HCl ratio, further indicating higher evolution degree. The Yangchuling monzogranites were derived from fractional crystallization of grandiorites, it is apparent that through differentiation the volatile components F and Cl, and W and Mo metals were gradually transferred from the granodiorite intrusion to the smaller monzogranitic porphyry, where the W-Mo ore system formed. This finding demonstrates that biotites are effective in indicating magma source and magma differentiation and can be used as a robust tool in mineral exploration.更多还原