吉林大学孙景贵团队研究了东北夹皮沟海沟拼贴带松江河地区早中侏罗世花岗岩杂岩的深部地质过程。该项研究成果发表在2025年7月2日出版的《地球化学学报》杂志上。

兴蒙造山带与华北克拉通中生代之间的深部地质过程对揭示甲皮沟—海沟拼合带岩浆构造演化及其对成矿作用的制约具有重要意义。

研究组报道了吉林松江地区中侏罗统花岗岩杂岩的年代学、地球化学和Sr-Nd-Hf同位素组成。花岗岩杂岩根据地质特征可划分为5个类群，对应的锆石U-Pb同位素年龄分别为177 Ma、172 Ma、169 Ma和168 ~ 167 Ma。这些花岗岩类具有钙碱性到高钾钙碱性，金属铝质到弱过铝质的i型特征，表现为LILEs （Rb、Sr、Ba）相对富集，HFSEs （Nb、Zr）相对富集。

地球化学分析表明，⁸⁷Sr/⁸⁶Sr初始比值为0.70633 ~ 0.70740，εNd(t)值为- 10.65 ~ - 13.23。锆石的εHf(t)值为- 16.9 ~ - 3.2。综合元素和Hf-Sr-Nd同位素特征表明，4组岩石的原始岩浆主要来源于增厚的太古宙下陨砾的部分熔融，但4组岩石表现出明显的陨砾污染迹象。岩浆形成过程中残留矿物组合从角闪洞相到榴辉岩相各不相同。这些发现表明，松江河地区岩浆活动可能是古太平洋板块在欧亚大陆下俯冲过程中拼贴带太古宙岩心的增生和剥离所致。

附：英文原文

Title: Deep geological processes of the early Middle Jurassic granitic complexes in the Songjianghe area, Jiapigou-Haigou collage zone, Northeast China: Evidence from zircon U–Pb dating, elemental geochemistry and Sr–Nd–Hf isotopes

Author: Zhang, Xinwen, Sun, Jinggui, Lin, Zuochao, Wang, Shu, He, Yunpeng

Issue&Volume: 2025-07-02

Abstract: The deep geologic processes between the Xing’an-Mongolian Orogenic Belt and the North China Craton in the Mesozoic are crucial to reveal the magmatic and tectonic evolution and their constraints on mineralization in the Jiapigou-Haigou collage zone. In this paper, We have presented the geochronology, geochemistry and Sr–Nd–Hf isotopic compositions of the Middle Jurassic granitic complexes in the Songjianghe area, Jilin Province. The granitic complexes can be categorized into four groups based on their geologic characteristics, with corresponding zircon U–Pb isotope ages of 177 Ma, 172 Ma, 169 Ma and 168–167 Ma, respectively. These granitoids exhibit calc-alkaline to high-K calc-alkaline, metaluminous to weakly peraluminous I-type characteristics, which show relative enrichment in LILEs (Rb, Sr, Ba) and depletion in HFSEs (Nb, Zr). Geochemical analyses reveal high initial 87Sr/86Sr ratios of 0.70633–0.70740, coupled with low εNd(t) values ranging from 10.65 to 13.23. The zircon analyses show similarly negative εHf(t) values ranging from 16.9 to 3.2. The integrated elemental and Hf–Sr–Nd isotopic signatures demonstrate that the primitive magmas of the four group rocks were primarily derived from partial melting of thickened Archean lower crust, with the exception of the Group IV rocks, which exhibit significant evidence of crustal contamination. The residual mineral assemblages during the magma-forming process varied from amphibole to eclogite facies. These findings indicate that magmatism in the Songjianghe region likely resulted from the accretion and delamination of the Archean crust in the collage zone during the subduction of the Paleo-Pacific Plate beneath the Eurasian continent.

DOI: 10.1007/s11631-025-00793-8

Source: https://link.springer.com/article/10.1007/s11631-025-00793-8