中国地质Issue(6)：1757-1770,14.
新疆西天山雾岭铁矿闪长岩地球化学及锆石U-Pb年代学
Geochemistry and zircon U-Pb geochronology of the diorite associated with the Wuling iron deposit in Western Tianshan Mountains, Xinjiang
摘要
Abstract
The Wuling diorite stock was intruded in volcaniclastic rocks of the Carboniferous Dahalajunshan Formation. Iron ore deposits were discovered in the contact zone or the interior of the stock. Zircon LA-ICP-MS U-Pb dating of the diorite yielded a weighted mean 206Pb/238U age of(307.7 ± 0.8)Ma. PositiveεNd(t) values vary from3.1 to 4.6, initial 87Sr/86Sr ratios are relatively low (0.7043-0.7046), and Nd model ages vary between 695Ma and 818Ma and fall on the mantle trend line in the 87Sr/86Sr(t) versusεNd(t) diagram. These data indicate a mantle source for the Wuling diorite. However, high Th values (1.61-3.24μg/g) and Th/Ta ratios (6.1-7.9) imply that the magma experienced a certain degree of contamination by continental crust. Therefore, the Wuling diorite magma might have been formed by the fractional crystallization of basaltic magma affected by crustal material. Although some traces of arc magmatism can be detected, the Wuling dirote was actually formed by intraplate magmatism. This diorite was emplaced when block rotation occurred between the Yili and Tarim plates after the termination of the West Tianshan accretionary orogeny. It is inferred that the generation of the magma was probably related to the detachment of an orogenic root zone or a local squeezing-stretching structural transition zone within the Yili plate.关键词
海相火山岩型铁矿/锆石U-Pb年龄/Sr/Nd同位素/雾岭/阿吾拉勒/西天山Key words
marine volcanogenic iron deposit/zircon U-Pb dating/Sr-Nd isotopes/Wuling/Awulale/Western Tianshan Mountains分类
天文与地球科学引用本文复制引用
段士刚,张作衡,魏梦元,田敬佺,蒋宗胜,李凤鸣,赵军,王厚方..新疆西天山雾岭铁矿闪长岩地球化学及锆石U-Pb年代学[J].中国地质,2014,(6):1757-1770,14.基金项目
国家科技支撑计划（2011BAB06B02）、国家自然科学基金项目（41203035）、国家重点基础研究发展计划（2012CB416803）和中国地质调查局地质矿产调查评价项目（1212011090300）联合资助。 （）
