Much of the crust of Iran and Anatolia, including their oldest exposed rocks, formed during an episode of intense convergent margin (arc) magmatism as a result of subduction of oceanic lithosphere beneath northern Gondwana from ca 620 Ma to ca 500 Ma, the Cadomian crust-forming event. Most igneous rocks formed between ca 570 and 525 Ma. Cadomian crust is well-known from western and southern Europe and from eastern North America but is much less well-known from Iran and Anatolia. We use published age and compositional data and contribute new data in order to better understand this ancient magmatic system. Cadomian magmatism included calc-alkaline igneous rocks of arc affinity in the main arc and alkalic igneous rocks that formed in a back-arc setting; these igneous rocks are associated with sedimentary rocks. Geochemical and isotopic modelling reveals that basaltic magmas were the main input, that these formed by partial melting in the upper mantle, and that basaltic magmas evolved further in deep crustal hot zones to form granitic magmas through a combination of assimilating older continental crust and fractional crystalization of basaltic magmas.

伊朗和安纳托利亚的大部分地壳，包括最古老的裸露岩石，是在冈瓦纳北部从约620 Ma到约500 Ma的大洋岩石圈俯冲的结果，是在剧烈的会聚边缘（弧）岩浆作用期间形成的。形成事件。之间形成最火成岩CA570和525 Ma。Cadomian地壳在西欧和南欧以及北美洲东部广为人知，但在伊朗和安纳托利亚却鲜为人知。我们使用已公布的年龄和成分数据，并贡献新数据，以便更好地了解这个古老的岩浆系统。Cadomian岩浆作用包括在主弧中具有弧亲和力的钙碱性火成岩和在后弧环境中形成的碱性火成岩。这些火成岩与沉积岩有关。地球化学和同位素模型表明，玄武岩浆是主要的输入，这些是由上地幔的部分熔融形成的，玄武岩浆在深地壳热区进一步演化，通过吸收较旧的大陆壳和分步结晶而形成了花岗岩岩浆。岩浆。