Abstract The Sanandaj-Sirjan zone (SSZ) of Iran comprises sedimentary and metamorphic basement rocks, which are generally regarded as having been derived from the southern active margin of the Eurasian plate. Within the SSZ, a number of Mesozoic to Cenozoic granitoid intrusions of various size, elongated in a NW-SE direction are exposed. With the benefit of precise age dating, geochemical and isotopic data over the past decade, the magmatic history of these intrusions has become clearer. This study presents further geochronological and geochemical data for previously dated and undated granitoids together with considerable zircon Lu-Hf isotopic data, which were limited in the past. Combined with previous work, these new data, including the finding of ca. 170 Ma adakite, lead to improved constraints on the Meso-Cenozoic tectonic evolution of Neo-Tethyan lithospheric subduction. The dominant early-middle Jurassic magmatism is proposed to have occurred with a major contribution of crustal components during the initiation of Neo-Tethyan subduction. Subsequent, late Jurassic magmatism suggests the involvement of lower crust partial melting in an extensional tectonic setting. Cretaceous magmatism almost ceased after formation of a flat slab, caused by a trench retreat rate exceeding that of slab roll-back. Late Paleocene-Eocene magma sources in the SSZ are dominated by mantle-derived input through an asthenospheric window with subordinate crustal contamination during the subduction of the Neo-Tethyan ridge-spreading center. This interpretation differs from Paleocene-Eocene magmatic flare-up proposed for the northern Iranian interior, which may have been driven by an episode of slab retreat or slab roll-back following Cretaceous flat slab subduction.

中文翻译：

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伊朗西北 Sanandaj-Sirjan 带花岗岩的地球化学、锆石 U-Pb 和 Hf 同位素：对新特提斯岩石圈俯冲过程中中新生代幕状岩浆活动的影响

摘要 伊朗的Sanandaj-Sirjan 带（SSZ）由沉积和变质基底岩组成，一般认为它们起源于欧亚板块南部活动边缘。在 SSZ 内，出露了许多在 NW-SE 方向拉长的不同大小的中新生代花岗岩侵入体。得益于过去十年精确的年代测定、地球化学和同位素数据，这些侵入体的岩浆历史变得更加清晰。本研究提供了先前测年和未测年花岗岩的进一步地质年代学和地球化学数据，以及过去有限的大量锆石 Lu-Hf 同位素数据。结合以前的工作，这些新数据，包括ca的发现。170 马埃达克石，导致对新特提斯岩石圈俯冲的中新生代构造演化的改进约束。主要的早中侏罗世岩浆活动被认为是在新特提斯俯冲开始期间地壳成分的主要贡献下发生的。随后的晚侏罗世岩浆作用表明下地壳部分熔融参与了伸展构造环境。白垩纪岩浆活动在平板形成后几乎停止，这是由于海沟的后退速度超过了平板回滚的速度。SSZ 晚古新世-始新世岩浆源主要是通过软流圈窗口的地幔来源输入，在新特提斯洋脊扩张中心俯冲期间具有次要的地壳污染。