额尔古纳地块北段霍洛台粗面安山岩锆石U-Pb年龄、岩石地球化学特征及构造背景  

Zircon U-Pb age,petrogeochemical characteristics,and tectonic setting of trachyandesite in the Huoluotai area,northern segment of the Erguna Block

作　　者：李海锋 孙永刚 许庆林 朱亚林 LI Haifeng;SUN Yonggang;XU Qinglin;ZHU Yalin(Qingyang Resources Exploration Institute,Gansu Coalfield Geology Bureau,Qingyang 745000,China;School of Resources and Civil Engineering,Suzhou University,Suzhou 234000,China;College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China)

机构地区：[1]甘肃煤田地质局庆阳资源勘查院,甘肃庆阳745000 [2]宿州学院资源与土木工程学院,安徽宿州234000 [3]山东科技大学地球科学与工程学院,山东青岛266590

出　　处：《山东科技大学学报（自然科学版）》2024年第4期45-56,共12页Journal of Shandong University of Science and Technology(Natural Science)

基　　金：宿州学院2022年博士科研启动基金项目(2022BSK009);宿州学院2023年博士后科研启动基金项目(2023BSH001)。

摘　　要：东北亚晚中生代火山岩成因是近年来的研究热点,额尔古纳地块北段地区受蒙古-鄂霍茨克和古太平洋构造域叠合作用的影响,导致火山岩成因更为复杂。本研究通过额尔古纳地块北段霍洛台地区粗面安山岩锆石U-Pb定年和岩石地球化学研究,探讨霍洛台粗面安山岩的岩石成因和构造背景。霍洛台粗面安山岩的锆石U-Pb加权平均年龄为137.8±1.8 Ma,形成于早白垩世。霍洛台粗面安山岩轻重稀土元素分馏明显(LREE/HREE=15.83~16.71),Eu异常不明显(δEu=0.84~0.88),岩石明显富集Rb、Ba和K等大离子亲石元素,亏损Th、U、Ta和Nb等高场强元素,属于高钾钙碱性系列。霍洛台粗面安山岩具有较高的Sr(754.24×10^(-6)~945.40×10^(-6))含量和Sr/Y比值(55.09~68.10),低的Y(13.22×10^(-6)~14.15×10^(-6))和Yb(0.97×10^(-6)~1.02×10^(-6))含量,属于典型的埃达克岩,由俯冲大洋板片部分熔融形成的,推测其形成与古太平洋板块俯冲回卷过程有关。The origin of Late Mesozoic volcanic rocks in the NE Asia has become a research hotspot in recent years.Affected by the superposition of the Mongol-Okhotsk and Paleo-Pacific Ocean tectonic domains,the origin of volcanic rocks in the northern segment of the Erguna Block is more complicated.This paper investigates the petrogenesis and tectonic setting of the trachyandesite through zircon U-Pb dating and geochemical data from the trachyandesite in the Huoluotai area,northern segment of the Erguna Block.The zircon U-Pb dating gave a weighted mean age of 137.8±1.8 Ma,implying that the formation age of the Huoluotai trachyandesites was Early Cretaceous.The Huoluotai trachyandesites show distinctly fractionation of light and heavy rare-earth elements(LREE/HREE=15.83~16.71),and have weak Eu anomaly(δEu=0.84~0.88).Enriched in the large-ion lithophile elements(e.g.,Rb,Ba,and K)and depleted in high-field-strength elements(e.g.,Th,U,Ta,and Nb),they belong to the high-K calc-alkaline series.With high Sr(754.24×10^(-6)~945.40×10^(-6))content and Sr/Y ratio(55.09~68.10),low Y(13.22×10^(-6)~14.15×10^(-6))and Yb(0.97×10^(-6)~1.02×10^(-6))contents,the Huoluotai trachyandesites belong to typical adakitic rocks derived from the partial melting of subducted oceanic plate,and their formation could be linked to the slab roll-back process of the Paleo-Pacific Ocean plate.

关 键 词：粗面安山岩 岩石成因 锆石U-PB定年 构造背景 额尔古纳地块 

分 类 号：P588.14[天文地球—岩石学]