The Ghaleh-Dezh metagranites in the northern Sanandaj–Sirjan Zone (SaSZ) in western Iran are found in a 0.5 km long by 0.3 km wide unit emplaced within the older Precambrian basement. New zircon U–Pb ages confirm that crystallization and emplacement of the protolith of the metagranites occurred at 312 ± 10 Ma and 298 ± 17 Ma in the Upper Carboniferous (Pennsylvanian) – Early Permian, which is consistent with the ages of recently discovered Palaeozoic granites in the northern SaSZ. The studied metagranitic body has been metamorphosed at lower greenschist facies and deformed in ductile–brittle regime due to subsequent reheating events during the Mesozoic. The rocks are metaluminous to slightly peraluminous granites with an A2-type affinity. Initial87Sr/86Sr ratios andεNd(t) contents vary from 0.7037 to 0.7130 and −0.70 to 0.34, respectively.143Nd/144Nd(i)values for the granitic rocks are fairly uniform at ∼0.5123. The geochemical and isotopic evidence indicates that these rocks were generated from a mantle magma with crustal contamination and fractional crystallization. Rb–Sr isochron and40Ar/39Ar K-feldspar ages are 274 Ma and 60–70 Ma, respectively. The older event,c.270 Ma, was likely related to the opening of Neotethys, whereas the younger ages likely relate to collisional events in the region during the closure of Neotethys.

中文翻译：

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伊朗 Sanandaj-Sirjan 带石炭纪 Ghaleh-Dezh 变花岗岩的岩石成因：新锆石 U-Pb 和 40Ar/39Ar 年龄和 Sr-Nd 同位素的约束

伊朗西部北部 Sanandaj-Sirjan 带 (SaSZ) 的 Ghaleh-Dezh 变花岗岩位于较旧的前寒武纪地下室中，该单元长 0.5 公里，宽 0.3 公里。新的锆石U-Pb年龄证实变花岗岩原岩的结晶和就位发生在上石炭统（宾夕法尼亚期）-早二叠世的312±10 Ma和298±17 Ma，这与最近发现的古生代花岗岩的年龄一致在 SaSZ 北部。由于随后的中生代再加热事件，所研究的变花岗质体已在下绿片岩相变质并在韧脆状态下变形。岩石为具有 A2 型亲和力的超铝质至略过铝质的花岗岩。最初的87锶/86Sr 比率和ε钕(吨) 含量分别在 0.7037 到 0.7130 和 -0.70 到 0.34 之间变化。143钕/144钕（一世）花岗质岩石的值相当一致，约为 0.5123。地球化学和同位素证据表明，这些岩石是由具有地壳污染和分级结晶的地幔岩浆产生的。Rb-Sr 等时线和40氩气/39Ar K-长石年龄分别为 274 Ma 和 60-70 Ma。较旧的事件，C。270 Ma，可能与新特提斯的打开有关，而较年轻的年龄可能与新特提斯关闭期间该地区的碰撞事件有关。