| 南羌塘索日卡地区三叠纪玄武岩锆石U-Pb年龄、地球化学特征及其地质构造意义 |
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| 关键词:basalts geochemistry zircon U-Pb age LA-ICP-MS ancient crust southern Qiangtang |
| 基金项目:国家自然科学基金项目(编号: 41602122; 42172103; U24A20597)、国家重大科技专项计划深地专项(编号: 2024ZD1001005)、中国地质调查局项目(编号: DD20230024; DD20230315)、西藏自治区科技计划项目(编号: XZ202401YD0006; XZ202403ZY0040)、湖北省自然科学基金项目(编号: 2023AFD206; 2023AFD230; 2024AFD401)、资源与生态环境地质湖北省重点实验室开放基金资助项目(编号: HBREGKFJJ-202302; HBREGKFJJ-202403)和地质过程与矿产资源国家重点实验室科技部专项经费(编号: GPMR202424) |
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| Zircon U-Pb Ages, Geochemistry, and Tectonic Significances of the Triassic Suorika Basalts in the Southern Qiangtang Terrane |
| The Triassic period marks a pivotal era for the tectonic transformation of the Qiangtang block. To gain a deeper understanding of the amalgamation and orogeny of the South and North Qiangtang micro-blocks during the Triassic, as well as the evolution of the ocean and continent, this study conducted LA-ICP-MS zircon in-situ U-Pb isotopic dating and petrochemical analysis on the basalts from the southern side of the central orogenic belt in the South Qiangtang region, specifically the Sorika basalts. The basalt samples yielded zircon U-Pb weighted average ages of (245.1±2.5) Ma and (250.7±2.9) Ma, and exhibited SiO2 contents ranging from 45.2% to 52.9%, K2O contents ranging from 2.42% to 3.60%, MgO contents ranging from 3.16% to 6.22%, and Mg# values of 51–60, suggesting that they belong to the shoshonitic and calc-alkaline basalt series. They are characterized by high Ti/V (28 to 31) and Zr/Y (>7.53) ratios, enrich-ment of LREE with (LREE/HREE)N=15.44 to 19.96 and no Eu anomaly, low Nb/La ratios (<1), and deple-tion of Nb and Ta. They are considered continental basalts, and the basaltic magma was probably gener-ated by partial melting of the mantle within the intraplate setting following the closure of the Long-mucu–Shuanghu Ocean. Xenocrystic zircon gains from the Suorika basalts recorded multiple magmatic events at 2 512 Ma, 1 816 Ma, 1 277 to 1 019 Ma, 800 Ma, 558 Ma, 420 Ma, and 340 Ma. These ancient crustal materials record information related to global Precambrian tectonic-magmatic-thermal events as-sociated with the evolution of supercontinents such as Columbia, Rodinia, and Gondwana. |
| CHEN Yun,CHEN Chong,JI Changjun,ZHU Jiang,LIU Jinming,ZHOU Lianfeng,WNAG Yaping.2025.Zircon U-Pb Ages, Geochemistry, and Tectonic Significances of the Triassic Suorika Basalts in the Southern Qiangtang Terrane[J].Acta Geoscientica Sinica,46(3):506-518. |
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