高校地质学报2018，Vol.24Issue(3)：340-352,13.DOI:10.16108/j.issn1006-7493.2017129
义敦岛弧带晚白垩世海子山二长花岗岩成因及其地质意义
Petrogenesis and Geological Significance of the Late Cretaceous Haizishan Monzogranite from the Yidun Island Arc
摘要
Abstract
The Yidun island arc is a significant component of Sanjiang Tethys composite orogenic belt. This paper presents zircon U-Pb age, whole-rock geochemistry and Sr-Nd-Pb isotopic data for the Haizishan granite from the Yidun island arc, aiming to explore its petrogenesis and geological significance. Zircon U-Pb dating results show that the Haizishan granite pluton was crystallized at 93.7± 1.1 Ma (MSWD=2.1, 2σ), indicating it was produced during early period of Late Cretaceous. The Haizishan granite is characterized by high SiO2and alkali, with A/CNK values of 1.04-1.12, showing a weakly peraluminous affinity. REEs of the granites are characterized by significant negative Eu anomalies with Eu/Eu* values of 0.05-0.32. The granitic rocks are enriched in Rb, Th, U, Ta, Pb but depleted in Ba, Sr. The εNd(t) values of the granites range from-4.8 to-3.4, with two-stage model age of 0.91-1.00 Ga. In combination with their Pb isotopic characteristics and the chemical signatures of low CaO/Na2O and high Al2O3/TiO2ratios, it is suggested that the Haizishan granite was originated from partial melting of argillaceous rocks with addition of minor mantle component. Based on a synthesis of their geochemistry, isotope characteristics and geological setting, we suggest that the Haizishan granite can be genetically grouped into A-type granites which were generated by partial melting of argillaceous rocks with minor involvement of mantle components in a post-collisional extension tectonic setting induced by upwelling of asthenosphere mantle.关键词
A型花岗岩/地球化学/锆石U-Pb定年/造山后伸展/义敦岛弧带Key words
A-type granite/geochemistry/zircon U-Pb dating/post-collisional extension/Yidun island arc belt分类
天文与地球科学引用本文复制引用
张方毅,赖绍聪,秦江锋..义敦岛弧带晚白垩世海子山二长花岗岩成因及其地质意义[J].高校地质学报,2018,24(3):340-352,13.基金项目
国家自然科学基金项目(41372067) （41372067）
国家自然科学基金委创新群体项目(41421002)联合资助 （41421002）
