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对出露于甘肃夏河地区,隶属西秦岭的印支晚期复式岩体的地质地球化学研究表明,其岩石具有与典型埃达克岩相似的特征:SiO2多数(72%~58%),高Al2O3(16.7%~14.6%),Sr多数大于(400×10-6),低Y(16×10-6~7×10-6)和Yb(1.7×10-6~0.56×10-6),明显亏损Nb和Ta,稀土元素分异强烈,富集LREE,低HREE,并有较弱的Eu负异常(δEu为0.9~0.4)在(La/Yb)N-YbN和Sr/Y-Y图解上样品主要落入埃达克质岩区域。该套埃达克质岩的厘定,对研究秦岭造山带晚古生代古特提斯洋的构造演化、地球动力学特征具有重要意义。
Geological and geochemical studies on the late Indosinian complex in the Xiahe area of Gansu, which belonged to the Western Qinling Mountains, showed that the rocks have similar characteristics to the typical adakites: most of SiO2 (72% -58%), high Al2O3 (16.7% ~ 14.6%), Sr (400 × 10-6), Y (16 × 10-6 ~ 7 × 10-6) and Yb (1.7 × 10-6 ~ 0.56 × 10-6) Significant loss of Nb and Ta, rare earth elements with strong differentiation, enrichment of LREE, low HREE, and weak Eu negative anomalies (δEu 0.9 ~ 0.4) on the (La / Yb) N-YbN and Sr / YY graphic samples Mainly fall into the adakite rock area. The determination of this set of adakitic rocks is of great significance for studying the tectonic evolution and geodynamic characteristics of the Late Paleozoic paleontitis in the Qinling orogenic belt.