The geochemistry of biotite crystals from thirty fertile and barren Silurian–Devonian granitoids of New Brunswick, Canada, was studied in situ using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry to investigate the suitability of biotite geochemistry as a diagnostic fertility index among these intrusions. The Fe 2+ /(Fe 2+ + Mg 2+ ) ratio of biotite varies as a function of intrusion metal affinity, increasing from Cu – Mo-related (mean of 0.56 ± 0.12), to Mo-related (mean of 0.69 ± 0.06) to Sn–W-related (mean of 0.77 ± 0.16), with barren granitoids lying between Cu–Mo and Mo types (mean of 0.66 ± 0.06). The results show a distinctive geochemical contrast between mineralized and barren samples. Compatible elements (Ti, Mg, Co, Ni, V, Cr, Ba, and Sr) decrease from barren to Cu–Mo, Mo, and Sn–W granitoids, whereas incompatible elements (Mn, Zn, Sn, W, Rb, Cs, and Li) show the opposite trend. These two trends might indicate higher degree of fractionation indicated by biotite chemistry in Sn–W-related granites. Furthermore, barren intrusions have the lowest water content (1–3 wt.% H 2 O), whereas Sn–W and Cu–Mo-related intrusions have between 3 and 6 wt.% H 2 O. Mo-bearing intrusions have a limited range of H 2 O contents (4–4.5 wt.%). A high degree of halogen enrichment related to degree of fractional crystallization results in enrichment of incompatible elements in the magmas associated with Sn – W mineralization and is reflected by the geochemical characteristics of biotite from these systems. New metallogenic classifications are introduced using ternary V–Na–Li (ppm) and Sn + W (ppm) versus Ga (ppm) to differentiate barren and mineralized granitic systems in New Brunswick.

中文翻译：

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使用岩浆黑云母化学区分加拿大新不伦瑞克的贫瘠和矿化志留纪-泥盆纪花岗岩

使用电子微探针和激光烧蚀电感耦合等离子体质谱法原位研究了来自加拿大新不伦瑞克三十个肥沃贫瘠的志留系-泥盆纪花岗岩的黑云母晶体的地球化学，以研究黑云母地球化学作为其中诊断肥力指数的适用性入侵。黑云母的 Fe 2+ /(Fe 2+ + Mg 2+ ) 比率随着侵入金属亲和力的变化而变化，从 Cu – Mo 相关（平均值为 0.56 ± 0.12）增加到 Mo 相关（平均值为 0.69 ± 0.06) 到 Sn-W 相关（平均值为 0.77 ± 0.16），贫瘠的花岗岩位于 Cu-Mo 和 Mo 类型之间（平均值为 0.66 ± 0.06）。结果显示矿化样品和贫瘠样品之间存在明显的地球化学对比。相容元素（Ti、Mg、Co、Ni、V、Cr、Ba 和 Sr）从贫瘠减少到 Cu-Mo、Mo 和 Sn-W 花岗岩，而不相容的元素（Mn、Zn、Sn、W、Rb、Cs 和 Li）则表现出相反的趋势。这两种趋势可能表明 Sn-W 相关花岗岩中黑云母化学表明的分馏程度更高。此外，贫瘠侵入体的含水量最低（1–3 wt.% H 2 O），而 Sn-W 和 Cu-Mo 相关侵入体的 H 2 O 为 3 到 6 wt.%。含钼侵入体具有H 2 O 含量范围有限（4–4.5 wt.%）。与分步结晶程度相关的高度卤素富集导致与 Sn-W 矿化相关的岩浆中不相容元素的富集，并反映在这些系统中黑云母的地球化学特征上。