近日，长安大学李永军团队研究了中国西北北天山造山带晚石炭世火山岩：岩石成因和构造意义。该研究于2026年4月7日发表在《地球化学学报》杂志上。

北天山造山带（NTB）是理解中亚造山带增生演化过程的关键区域。然而，其晚石炭世的构造背景长期以来一直存在争议。

研究组通过提供新的火山岩年代学和地球化学数据，旨在阐明这一问题。火山岩由玄武岩、安山岩、英安岩和流纹岩组成。激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）锆石U-Pb定年获得的年龄分别为：310.1 Ma（玄武岩）、304.8 Ma（安山岩）、308.1 Ma和307.0 Ma（两个英安岩样品）以及313.5 Ma（流纹岩）。地球化学数据表明，钙碱性的中基性火山岩（玄武岩和安山岩）属于同源岩浆产物，富集Ba、K、U、Pb，亏损Nb、Ta、Ti、Zr、Hf。

它们起源于经流体交代的亏损地幔楔。然而，由于俯冲相关流体的输入量和部分熔融程度存在差异，中基性火山岩在微量元素组成上表现出细微差别。I型英安岩富集Ba、K、U、Pb，亏损Nb、Ta、Ti，是由基性下地壳部分熔融形成。A型流纹岩以富集Rb、Th，亏损Ba、Sr、P为特征，与长英质上地壳部分熔融的成因一致。区域岩浆作用和成矿作用的时空分布模式表明，晚石炭世北天山造山带处于洋脊俯冲背景之下。

附：英文原文

Title: Late Carboniferous volcanic rocks in the North Tianshan Orogenic Belt, NW China: petrogenesis and tectonic implications

Author: Zhang, Jianye, Li, Yongjun, Li, Wei, Wang, Qian, Wang, Panlong, Fu, Hao, Yang, Gaoxue

Issue&Volume: 2026-04-07

Abstract: The North Tianshan Orogenic Belt (NTB) is a crucial region for understanding the accretionary evolution of the Central Asian Orogenic Belt. However, its Late Carboniferous tectonic setting has long been controversial. This study presents new geochronological and geochemical data on volcanic rocks to shed light on this issue. The volcanic rocks are composed of basalt, andesite, dacite, and rhyolite. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb dating yielded ages of 310.1 Ma (basalt), 304.8 Ma (andesite), 308.1 Ma and 307.0 Ma (two dacite samples), and 313.5 Ma (rhyolite). Geochemical data demonstrate that the calc-alkaline intermediate-mafic volcanic rocks (basalts and andesites) belong to co-genetic magmatic products, enriched in Ba, K, U, and Pb, and depleted in Nb, Ta, Ti, Zr, and Hf. They originated from fluid-metasomatized depleted mantle wedge. However, due to differences in subduction-related fluid input and the degree of partial melting, the intermediate-mafic volcanic rocks show slight differences in trace element composition. The I-type dacites, enriched in Ba, K, U, and Pb but depleted in Nb, Ta, and Ti, were derived from the partial melting of mafic lower continental crust. The A-type rhyolites are characterized by enrichment in Rb and Th and depletion in Ba, Sr, and P, consistent with derivation from partial melting of felsic upper continental crust. The spatiotemporal distribution patterns of regional magmatism and mineralization suggest that a ridge subduction setting was operating in the NTB during the Late Carboniferous.

DOI: 10.1007/s11631-026-00869-z

Source: https://link.springer.com/article/10.1007/s11631-026-00869-z