高校地质学报2016，Vol.22Issue(2)：231-241,11.DOI:10.16108/j.issn1006-7493.2015123
博格达山东段苏吉山A型花岗岩地球化学特征、LA-ICP-MS定年及其构造意义
Lithogeochemistry and LA-ICP-MS Zircon U-Pb Age and Its Tectonic Significance of Sujishan A-type Granite Pluton, Eastern Bogda Mountains
摘要
Abstract
The Sujishan granite, formed at Balikun, Xinjiang province, is a ferro-edenite alkali-feldspar granite, locating tectonically at the eastern segement of the Bogda orogenic belt. Containing high contents of SiO2, K2O+Na2O, NK/A and low content of Al2O3, it invariably exhibits light rare earth elements (LREE) enrichment with weak negative Eu anomalies and enrichment of LILE and HFSE with the depletion of Cs, Sr, P, Ti. The element combinations of high HFSE (Zr+Nb+Ce+Y) range from 451 × 10-6 to 674 × 10-6 and zircon-saturation temperature lies within 841℃to 883℃. These characteristics show that it belongs to A-type granite, and specifically most of the samples fall into the range of A2-type granite according to the discrimination diagrams. The amphibole as rock-forming mineral belongs to calcic amphibole group, ferro-edenite hronblende subgroup, which is characterized by Al2O3 2.9%~4.5%and Si/(Si+Ti+A1) 0.88~0.93, implying a crustal source. The zircon LA-ICP-MS U-Pb dating analysis suggests the emplacement age of Sujishan granite is ca. 301.5±2.4Ma, which belongs to the Gzhelian stage of the late Carboniferous. Sujishan A-type granite with crustal-derived amphiboles differs from A1-type granitoid representing a stretching mechanics related with mantle plume or rifting. Additionally, the emplacement time at middle and late of rifting differs from A2-type granitoid formed at a post-orogenic tectonic stage. In combination with granites emplaced at adjacent region, the Sujishan A-type granite marked a limited stretching mechanics related with rifting, which may be the product of oblique subduction of the paleo-Asian Ocean plate along the Kalameili subduction belt .关键词
A型花岗岩/裂谷作用/博格达裂谷/卡拉麦里蛇绿岩带Key words
A-type granite/rifting/Bogda rift/Kalameili ophiolite belt分类
天文与地球科学引用本文复制引用
雷万杉,郭俊锋,马继海,肖良,李相传,刘军锋,李勇..博格达山东段苏吉山A型花岗岩地球化学特征、LA-ICP-MS定年及其构造意义[J].高校地质学报,2016,22(2):231-241,11.基金项目
长安大学中央高校基本科研业务费项目（2014G1271067，310827153408，310827151057）；陕西省自然科学基金（016JM4001）联合资助 （）
