地质通报2017，Vol.36Issue(7)：1129-1146,18.
新疆大红柳滩地区奇台达坂北侧新近系泉水沟组火山岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及其地质意义
LA-ICP-MS zircon U-Pb ages, geochemical characteristics and geo?logical significance of the Neogene Quanshuigou Formation volcanic rocks in the north of Dahongliutan-Qitaidaban area, Xinjiang
摘要
Abstract
The Quanshuigou Formation volcanic rocks are located in northern Dahongliutan-Qitadaban area, western Kunlun Mountains, Xinjiang. The volcanic rocks are mainly composed of pyroxene andesite, pyroxene latite, and biotite trachyte. LA-ICP-MS zircon dating indicates that the volcanic rocks were emplaced at 3.71 ± 0.05Ma, suggesting that the crystallization age of the Quanshuigou Formation volcanic rocks is Neogene Pliocene. Geochemical analysis shows that major elements are characterized by high Al2O3 (13.56%~14.32%) and K2O (4.46%~5.79%), but low Na2O (3.68%~4.40%), TiO2 (1.09%~1.48%) and MgO (2.64%~5.18%), thus belonging to shoshonite series. In addition, they are enriched in total REE (550×10-6~612×10-6), and the samples are en?riched in LREE (light rare earth elements) and depleted in HREE (heavy rare earth elements) with weak Eu anomalies (δEu=0.55~0.63). The chondrite-normalized REE patterns show rightly-inclined type, and the olcanic rocks have rich LILE(such as K, Rb, Ba, Th, U and Pb)but poor high field strength elements (such as Ti, Nb, Ta, and P). They have typical characteristics of orogenic potassic volcanic rocks.Studies show that the rocks were formed by the partial melting enriched mantle sources mixed with a small amount of materials of the upper crust. Combined with the data of regional geology, the authors hold that the formation of the orogenic belt was related to NNW-striking thrust nappe of Karakoram-Tianshuihai along Dahongliutan-Quanshuigou fault and Tianshuihai-Guozhacuo fault in the Pliocene. At that time,the volcanic rocks were formed.关键词
钾质火山岩/LA-ICP-MS锆石U-Pb年龄/地球化学/板内造山/地幔熔融/泉水沟组/奇台达坂Key words
potassic volcanic rocks/LA-ICP-MS zircon U-Pb ages/geochemistry/intraplate orogeny/mantle melting/Quans⁃huigou Formation/Qitaidaban分类
天文与地球科学引用本文复制引用
赵江林,曾忠诚,贺宁强,杜彪,王星,袁璋..新疆大红柳滩地区奇台达坂北侧新近系泉水沟组火山岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及其地质意义[J].地质通报,2017,36(7):1129-1146,18.基金项目
中国地质调查局项目《新疆西昆仑地区1:5万I44E002006等四幅区调》(编号:1212011220654)、《新疆阿尔金地区1:5万J45E010020等六幅区域地质矿产调查》(编号:12120114081901)、《新疆阿尔泰1:5万M45E018012等五幅区域地质矿产调查》(编号:12120114040601) （编号:1212011220654）
