摘要
西秦岭郎木寺地区发育了大量的火山岩,是探讨秦岭造山带印支期岩浆作用的重要窗口。目前,关于郎木寺组火山岩的形成时代尚未有很好的约束。据此,笔者对郎木寺组角闪安山岩开展了详细的LA-ICP-MS锆石U-Pb年代学研究。CL图像显示,郎木寺组角闪安山岩的锆石结构表现出典型的岩浆成因特征。锆石U-Pb定年结果显示,角闪安山岩具略有差异的两组年龄,加权平均年龄分别为(221.8±1.2)Ma和(210.6±2.1)Ma。因此,郎木寺组角闪安山岩的形成时代为晚三叠世。结合前人已有成果,笔者认为郎木寺组火山岩代表了秦岭印支期造山作用重要的岩浆事件产物,形成于同碰撞挤压的构造环境。
Volcanic rocks are wide spread in Langmusi area of western Qinling,which is an important window to study the Indosinian magmatism of the Qinling Orogen.However,the formation age of langmusi volcanic rocks is not well constrained.In this contribution,a detailed study of LA-ICP-MS zircon U-Pb geochronology for the hornblende andesites from Langmusi Formation was conducted.CL images show that the internal structures of zircon from hornblende andesites show typical magmatic origin.Zircon U-Pb dating results demon-strate that the horndiorite andesites have slightly different ages,with weighted average ages of(221.8±1.2)Ma and(210.6±2.1)Ma respectively.Therefore,the horndiorite andesites of langmusi Formation were formed the Late Triassic period.Combining with previous studies,we argue that the volcanic rocks of the Langmusi Formation represent an important magmatic event of the Qinling Indosinian orogeny,which were formed in a syn-collisional tectonic setting.
作者
冉亚洲
陈涛
梁文天
李阳
申琪
李传志
RAN Yazhou;CHEN Tao;LIANG Wentian;LI Yang;SHEN Qi;LI Chuanzhi(State Key Laboratory for Continental Dynamics,Northwest University,Xi’an 710069,Shaanxi,China;Shaanxi Institute of Surverying and Mapping of Land LTD,Xi’an 710054,Shaanxi,China;Ocean University of China,Qingdao 266100,Shandong,China)
出处
《西北地质》
CSCD
北大核心
2024年第1期110-121,共12页
Northwestern Geology
基金
国家自然科学基金“秦岭造山带早中生代花岗岩构造及其与造山作用关系”(41672200)
“秦岭造山带中生代构造-岩浆演化与构造体制转换研究”(42172230)
“秦岭晚中生代花岗岩的构造研究及其对陆内造山过程的约束”(41802212)联合资助。
