Abstract The petrogenesis of granites with high Sr/Y signatures similar to adakitic rocks in continental settings is much debated. It is especially controversial whether these rocks are indicative of high-pressure magmatism (i.e., partial melting or crystallization fractionation) related to a thickened crust, or their high Sr/Y signatures are merely inherited from a high Sr/Y source. To address this, new chronological and geochemical data are presented for high Sr/Y granites from the Riluku batholith in eastern Tibetan Plateau. Zircon U-Pb dating and amphibole barometry suggest a final granite crystallization stage of ca. 207 Ma and an emplacement depth of ~14 km (~ 4 kbar), respectively. They are geochemically characterized by high Sr and low Y contents (481–1195 ppm and 6.62–20.6 ppm, respectively) with high Sr/Y and (La/Yb)N ratios (35–112 and 15–113, respectively). Enriched isotope character of the high Sr/Y granites, in combination with regional tectonics, indicates that these rocks are unlikely to be derived from partial melting of subducting oceanic crust. Low Cr (0.8–1.0 ppm), Ni (0.9–3.2 ppm), and Mg# (24–41) suggest that derivation from the partial melting of delaminated lower crust is also unlikely. Water-fluxed partial melting of crustal rocks at low pressure, which preferentially consumes plagioclase over micas, is inconsistent with the high contents of Rb (mostly >150 ppm) and low Sr/Rb ratios (mostly

中文翻译：

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青藏高原东部松潘-甘孜褶皱带晚三叠世高Sr/Y花岗岩成因的源压效应

摘要 与大陆环境中的埃达克岩类似的具有高 Sr/Y 特征的花岗岩的成岩作用存在很大争议。这些岩石是否表明与增厚的地壳有关的高压岩浆作用（即部分熔融或结晶分馏），或者它们的高 Sr/Y 特征仅仅是继承自高 Sr/Y 源，这一点尤其有争议。为了解决这个问题，我们提供了青藏高原东部日鲁库岩基高 Sr/Y 花岗岩的新年代学和地球化学数据。锆石 U-Pb 测年和角闪石气压计表明花岗岩的最终结晶阶段约为 207 Ma 和侵位深度分别为 ~14 km (~ 4 kbar)。它们的地球化学特征是高 Sr 和低 Y 含量（481-1195 ppm 和 6.62-20.6 ppm，分别）具有高 Sr/Y 和 (La/Yb)N 比率（分别为 35-112 和 15-113）。高 Sr/Y 花岗岩的丰富同位素特征，结合区域构造，表明这些岩石不太可能来自俯冲洋壳的部分熔融。低 Cr (0.8-1.0 ppm)、Ni (0.9-3.2 ppm) 和 Mg# (24-41) 表明也不太可能来自分层下地壳的部分熔融。地壳岩石在低压下的水熔部分熔化，优先消耗斜长石而不是云母，与高含量的 Rb（大多数 >150 ppm）和低 Sr/Rb 比值（主要是 表明这些岩石不太可能来自俯冲洋壳的部分熔融。低 Cr (0.8-1.0 ppm)、Ni (0.9-3.2 ppm) 和 Mg# (24-41) 表明也不太可能来自分层下地壳的部分熔融。地壳岩石在低压下的水熔部分熔化，优先消耗斜长石而不是云母，与高含量的 Rb（大多数 >150 ppm）和低 Sr/Rb 比值（主要是 表明这些岩石不太可能来自俯冲洋壳的部分熔融。低 Cr (0.8-1.0 ppm)、Ni (0.9-3.2 ppm) 和 Mg# (24-41) 表明也不太可能来自分层下地壳的部分熔融。地壳岩石在低压下的水流部分熔融，优先消耗斜长石而不是云母，与高含量的 Rb（大多数 >150 ppm）和低 Sr/Rb 比（大多数