%0 Journal Article %T 北山造山带中段早古生代–晚古生代岩浆作用——对古亚洲洋俯冲–闭合过程的制约
Early Paleozoic-Late Paleozoic Magmatism in the Middle Part of the Beishan Orogenic Belt—Constraints on the Paleo-Asian Ocean Subduction-Closure Process %A 胡萧萧 %J Advances in Geosciences %P 697-705 %@ 2163-3975 %D 2025 %I Hans Publishing %R 10.12677/ag.2025.155068 %X 北山地区位于中亚造山带南缘，是研究古亚洲洋演化的关键研究区域。花岗岩作为造山带的重要物质组成，岩浆成分演化能够有效示踪构造环境转变。北山造山带中部广泛出露古生代花岗岩体，为研究俯冲至碰撞阶段的岩浆演化过程提供了良好条件。文章收集了牛圈子地区晚志留世–早泥盆世中酸性岩浆岩数据，通过系统对比区域同期地质体的构造属性与地球化学特征，为北山造山带中段该时期的地质演化提供新的证据约束。研究表明：1) 早古生代(中奥陶世–早泥盆世)北山中部发育以钙碱性I型花岗岩、埃达克质岩及弧火山岩为特征的岩浆组合，形成于俯冲背景下的活动陆缘环境，岩浆成分与同位素特征指示地壳增厚及洋壳俯冲作用；2) 早泥盆世开始，岩浆活动减弱并出现S型、A型花岗岩组合，地球化学特征显示构造环境由挤压向伸展转换，同时伴随双峰式岩浆岩、磨拉石建造及沉积环境由深海向陆相的转变，表明红柳河–牛圈子–洗肠井蛇绿混杂岩带代表的古亚洲洋盆发生闭合；3) 构造体制转换的时限受控于弧–弧碰撞事件，蛇绿岩抬升、不整合接触及碰撞后伸展岩浆作用共同佐证了北山洋盆闭合的动力学过程。本研究为揭示中亚造山带南缘多阶段增生–碰撞演化提供了关键约束。
The Beishan region, situated at the southern margin of the Central Asian Orogenic Belt (CAOB), serves as a pivotal area for investigating the evolution of the Paleo-Asian Ocean. Granite, as a crucial component of orogenic belts, with its magmatic compositional evolution, can effectively trace the transitions of tectonic settings. The central part of the Beishan orogenic belt is extensively exposed to Paleozoic granitic plutons, providing favorable conditions for studying the magmatic evolution processes from subduction to collision stages. This study collected data on the Middle-Late Silurian to Early Devonian intermediate-acidic magmatic rocks in the Niujuanzi area. By systematically comparing the tectonic attributes and geochemical characteristics of contemporaneous geological bodies in the region, new evidence constraints are provided for the geological evolution of the central Beishan orogenic belt during this period. The research findings are as follows: 1) During the Early Paleozoic (Middle Ordovician-Early Devonian), a magmatic assemblage characterized by calc alkaline I type granites, adakites, and arc volcanic rocks developed in the central Beishan. This assemblage formed in an active continental margin environment under a subduction setting. The compositional and isotopic characteristics of the magmas indicate crustal thickening and oceanic crust subduction.2) Starting from the Early Devonian, magmatic activity weakened, and a combination of S type and A type granites emerged. Geochemical features suggest a transition of the tectonic environment from compression to extension. Simultaneously, the occurrence of bimodal magmatism, molasse deposits, and a sedimentary environment shift from deep-sea to continental facies indicate the closure of the Paleo-Asian Ocean basin represented by the Hongliuhe-Niujuanzi-Xichangjing ophiolitic mélange belt.3) The timing of the tectonic regime transition is controlled by arc-arc %K 中亚造山带， %K 北山地区， %K 花岗岩
Central Asian Orogenic Belt %K Beishan Area %K Granite %U http://www.hanspub.org/journal/PaperInformation.aspx?PaperID=115224