The roles of the mantle in generating granites and the extent of crust-mantle interaction are fundamental topics to our understanding of Sn mineralization. In this study, we report geochronological, geochemical, and Sr-Nd–Hf isotopic data for the granites, and muscovite ⁴⁰Ar/³⁹A isotopic data of the greisen type Sn ores, in the Dashunlong Sn deposit, Dayishan orefield, middle Qinzhou-Hangzhou metallogenic belt. LA–ICP–MS zircon U–Pb dating for the medium-fine grained- and coarse grained-biotite monzogranite of Dayishan pluton yields emplacement ages of 154.6 ± 1.2 Ma (MSWD = 0.73) and 154.7 ± 1.6 Ma (MSWD = 1.9), respectively, which are consistent with the muscovite ⁴⁰Ar/³⁹Ar plateau age of 151.1 ± 0.9 Ma (MSWD = 0.09) for the greisen-type Sn ores. It is indicated that the Sn mineralization in the Dashunlong deposit is related to the Late Jurassic Dayishan granite. The granite shows the geochemical features of highly fractionated A-type granite: 1) high 10,000 Ga/Al ratios of 2.95–3.88; 2) high Zr + Nb + Ce + Y contents of 292–637 ppm; 3) high TFeO/(TFeO* + MgO) ratios of 0.86–0.97; and 4) high Rb/Sr ratios of 2.80–18.8. Whole rocks isotopes show that this granite has variable initial ⁸⁷Sr/⁸⁶Sr ratios (0.71607–0.72437), negative ε_Nd(t) values (−7.20 to −5.46), and two-stage Nd model ages of 1530–1388 Ma. LA–MC–ICP–MS zircon Lu-Hf isotopes show that the medium-fine-grained monzogranite has ε_Hf(t) values of −0.94–2.20 and two-stage Hf model ages of 1298–1059 Ma, whereas the coarse-grained biotite monzogranite has relatively high ε_Hf(t) values of −0.84–5.95 and two-stage Hf model ages of 1257–823 Ma. Different Hf and Nd isotopes indicate that the Nd-Hf isotopic decoupling occurs in the Dayishan granite, which was likely caused by the partial melting of the rocks containing abundant high Lu/Hf minerals. The magma of the Dayishan granite is reduced, highly fractionated, and enriched in Sn and F, resulting in large-scale Sn mineralization in the Dayishan orefield. It is proposed that these granites are originated from melts mixed by crustal- and mantle constituents and are formed in an extensional setting caused by the subduction of the Palaeo-pacific plate. A two end-member modeling indicates that ca. 10–20 percent of mantle-derived melts were likely involved in the formation of the Dayishan granites.

地幔在生成花岗岩中的作用以及壳幔相互作用的程度是我们理解锡矿化的基本主题。在这项研究中，我们对于花岗岩报告地质年代，地球化学和Sr-的Nd-Hf同位素数据，和白云母⁴⁰的Ar / ³⁹云英岩类型的同位素数据的Sn矿石，在Dashunlong Sn沉积，矿田大义山，中Qinzhou-杭州成矿带。大伊山岩体中细粒和粗粒黑云母二长花岗岩的LA-ICP-MS锆石U-Pb定年结果为154.6±1.2 Ma（MSWD = 0.73）和154.7±1.6 Ma（MSWD = 1.9），分别与白云母⁴⁰ Ar/ ³⁹greisen 型锡矿的 Ar 高原年龄为 151.1 ± 0.9 Ma (MSWD = 0.09)。表明大顺龙矿床的锡矿化与晚侏罗世大伊山花岗岩有关。花岗岩显示出高度分异 A 型花岗岩的地球化学特征：1) 10,000 Ga/Al 比值高，为 2.95-3.88；2) Zr + Nb + Ce + Y 含量高，为 292–637 ppm；3) 0.86–0.97 的高 TFeO/(TFeO* + MgO) 比率；4) 2.80–18.8 的高 Rb/Sr 比率。全岩同位素显示，该花岗岩具有可变的初始⁸⁷ Sr/ ⁸⁶ Sr 比值 (0.71607–0.72437)、负 ε _Nd (t) 值（-7.20 至 -5.46）和 1530-1388 Ma 的两阶段 Nd 模型年龄。LA-MC-ICP-MS锆石Lu-Hf同位素表明中细粒二长花岗岩具有ε _Hf(t) -0.94-2.20 的值和 1298-1059 Ma 的两阶段 Hf 模型年龄，而粗粒黑云母二长花岗岩具有相对较高的 ε _Hf(t) -0.84–5.95 的值和 1257–823 Ma 的两阶段 Hf 模型年龄。不同的Hf和Nd同位素表明大伊山花岗岩中发生了Nd-Hf同位素解耦，这可能是由于含有丰富的高Lu/Hf矿物的岩石部分熔融所致。大伊山花岗岩岩浆被还原、高度分异、富集锡、氟，导致大伊山矿田大规模成矿。推测这些花岗岩起源于地壳和地幔成分混合的熔体，形成于古太平洋板块俯冲引起的伸展环境中。两个端元建模表明，ca。10-20% 的地幔熔体可能参与了大伊山花岗岩的形成。