The Pirrit Hills are located in the Ellsworth–Whitmore Mountains of West Antarctica. The Pirrit Hills granite exhibits significant negative Eu anomalies (Eu/Eu* = 0.01~0.25) and a REE tetrad effect indicating intensive magmatic differentiation. Whole-rock Rb-Sr and Sm-Nd geochronologic analysis of the Pirrit Hills granite gave respective ages of 172.8 ± 2.4 Ma with initial ⁸⁷Sr/⁸⁶Sr = 0.7065 ± 0.0087 Ma and 169 ± 12 Ma with initial ¹⁴⁴Nd/¹⁴³Nd = 0.512207 ± 0.000017. The isotopic ratio data indicate that the Pirrit Hills granite formed by the remelting of Mesoproterozoic mantle-derived crustal materials. Both chondrite-normalized REE patterns and Sr-Nd isotopic data indicate that the Pirrit Hills granite has geochemical features of chondrite-normalized REE patterns indicating that REE tetrad effects and negative Eu anomalies in the highly fractionated granites were produced from magmatic differentiation under the magmatic-hydrothermal transition system.

中文翻译：

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南极西部A型皮里特山花岗岩的稀土元素四元组效应和Sr-Nd同位素系统学

皮里特山位于南极洲西部的埃尔斯沃思-惠特莫尔山脉。Pirrit Hills 花岗岩表现出显着的 Eu 负异常（Eu/Eu* = 0.01~0.25）和 REE 四分体效应，表明岩浆分异强烈。Pirit Hills 花岗岩的全岩 Rb-Sr 和 Sm-Nd 年代学分析给出了各自的年龄为 172.8 ± 2.4 Ma，初始⁸⁷ Sr/ ⁸⁶ Sr = 0.7065 ± 0.0087 Ma 和 169 ± 12 Ma，初始¹⁴⁴ Nd/ ¹⁴³钕 = 0.512207 ± 0.000017。同位素比数据表明，皮里特山花岗岩是由中元古代地幔衍生的地壳物质重熔形成的。球粒陨石归一化的 REE 模式和 Sr-Nd 同位素数据均表明 Pirrit Hills 花岗岩具有球粒陨石归一化 REE 模式的地球化学特征，表明高分异花岗岩中的 REE 四分体效应和负 Eu 异常是由岩浆作用下的岩浆分异产生的。水热转换系统。