The Sanshilipu monzogranites is located in the northern margin of the South Qinling Block, with an outcrop of about 10 km², and as an intrusion into Palaeozoic Danfeng ophiolitic mélange. The samples consist mainly of plagioclase, K‐feldspar, quartz, biotite, and minor titanite, apatite, magnetite, with contents of SiO₂ (61.73–68.49%), Al₂O₃ (14.58–16.61%), K₂O + Na₂O (5.79–8.87%), MgO (1.07–2.91%), and low TiO₂ (0.55–0.83%), similar to those of I‐type granite. They also show high concentrations of LREE, Pb, and Sr, slightly negative Eu, but low HREE, Nb, Ta, and Y. High Sr and Sr/Y, low Y characteristics are similar to those of adakite. High precision LA‐ICP‐MS U–Pb dating and trace element analysis of zircon in the Sanshilipu granite yielded a concordant age of 205 ± 1 Ma. This age is apparently younger than the closure age of the Mian‐Lue Ocean (242–221 Ma). We propose that the Sanshilipu monzogranites formed by magma mixing of thickened lower crust and limited mantle‐derived mafic magma during post‐collision of the South China and North China blocks.

中文翻译：

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北秦岭造山带晚三叠世三世里铺辉长花岗岩的成因

Sanshilipu monzogranites位于南秦岭地块的北缘，露头约10 km ²，是对古生代丹峰蛇绿混杂岩的侵入。样品主要由斜长石，钾长石，石英，黑云母和次要钛铁矿，磷灰石，磁铁矿组成，其含量为SiO ₂（61.73–68.49％），Al ₂ O ₃（14.58–16.61％），K ₂ O + Na ₂ O（5.79–8.87％），MgO（1.07–2.91％）和低TiO ₂（0.55-0.83％），类似于I型花岗岩。它们还显示出高浓度的LREE，Pb和Sr，Eu稍为负，但是低的HREE，Nb，Ta和Y。高的Sr和Sr / Y和低的Y特性类似于蓝绿色。Sanshilipu花岗岩中锆石的高精度LA-ICP-MS U-Pb测年和微量元素分析得出一致的年龄为205±1 Ma。这个年龄显然比绵湖洋的封闭年龄（242-221 Ma）要年轻。我们认为，在华南和华北地块的后碰撞过程中，由加厚的下地壳和有限的地幔衍生的镁铁质岩浆的岩浆混合形成的三石坡普长花岗岩。