The Boein-Miandasht Complex (BMC) in the central part of the Sanandaj-Sirjan Zone, western Iran, is composed of metamorphic rocks, and gabbro, gabbro-diorite, and granite intrusions, in which co-magmatic mingling structures are commonly found. Zircon U-Pb ages demonstrate that crystallization of the granitic rocks occurred during the Late Jurassic (158 ± 5 Ma to 156 ± 4 Ma). Whole-rock granite geochemistry indicates low abundances of MgO (0.43–1.16 wt%), CaO (0.92–2.34 wt%), P₂O₅ (0.12–0.20 wt%) and Sr (72.2–254 ppm), high contents of SiO₂ (66.9–72.0 wt%), alkalis (Na₂O + K₂O = 8.04–8.94 wt%), Rb (153–213 ppm), high field-strength elements (HFSE), rare earth elements (REE), and high FeO^t/MgO ratios. The rocks are calc-alkalic to alkali-calcic and metaluminous to slightly peraluminous, typical characteristics of ferroan A-type granites. Chondrite-normalized REE diagrams display slight enrichment of light REE, flat HREE patterns and significant negative Eu anomalies. The primitive mantle-normalized multi-element variation diagrams show negative Eu, Nb, Sr, P and Ti anomalies. Both REE and other incompatible elements are consistent with A-type granite affinities for these rocks. The thinning of the continental crust and injection of hot mafic magmas within the crust were probably responsible for the partial melting of the lower crust to produce A-type granitic magmas in the region. This process is consistent with an extensional tectonic regime in the central part of the Sanandaj-Sirjan Zone during the Late Jurassic.

伊朗西部Sanandaj-Sirjan区中部的Boein-Miandasht复杂体（BMC）由变质岩，辉长岩，辉长辉闪闪岩和花岗岩侵入体组成，其中通常存在共岩浆混合结构。锆石的U-Pb年龄表明，侏罗纪晚期（158±5 Ma至156±4 Ma）发生了花岗岩的结晶。全岩花岗岩地球化学表明，MgO（0.43–1.16 wt％），CaO（0.92–2.34 wt％），P ₂ O ₅（0.12–0.20 wt％）和Sr（72.2–254 ppm）的丰度低， SiO ₂（66.9–72.0 wt％），碱（Na ₂ O + K ₂ O = 8.04–8.94 wt％），Rb（153–213 ppm），高场强元素（HFSE），稀土元素（REE）且FeO ^t高/ MgO比。岩石是钙-碱到碱-钙和金属-略高铝质的铁铝A型花岗岩的典型特征。球粒晶归一化的REE图显示了轻REE，平坦的HREE模式和显着的负Eu异常的轻微富集。原始的地幔归一化多元素变化图显示负Eu，Nb，Sr，P和Ti异常。REE和其他不相容元素都与这些岩石的A型花岗岩亲和力一致。大陆壳的变薄和地壳内热镁铁质岩浆的注入可能是造成下地壳部分融化从而在该地区产生A型花岗岩岩浆的原因。这一过程与侏罗纪晚期桑那达杰－瑟里扬带中部的伸展构造政体相一致。