岩石矿物学杂志2011，Vol.30Issue(3)：543-552,10.
内蒙古东七一山碱长花岗岩的地球化学特征和成因
Geochemical characteristics and petrogenesis of Dongqiyishan alkali feldspar granite,Inner Mongolia
摘要
Abstract
The Dongqiyishan alkali feldspar granite is the largest rare metal mineralized granite in Beishan area, Iinner Mongolia, and is of remarkable representative significance in similar rock masses.Based on previous research result of petrologic and metallogenetic characteristics, the authors performed a lot of detailed work on geochemistry, isotope geochemistry and geochronology.Petrochemical research shows that the granite is rich in silicon and alkali, and poor in Fe, Ti, Mg and Mn, thus belonging to high-k calc-alkaline series.Petrochemical research shows that the granite is strongly depleted in Eu(δEu＜0.1), Ba, Sr, P, Ti and obviously enriched in Rb, Nb + Ta, W, Mo, Bi, Li, etc.The Rb-Sr isochron age is 128.2 + 1.1 Ma, with ISr being 0.70979, suggesting that the original rock had obvious crustal characteristics.Relative to values of the depleted mantle, the two types of rocks have somewhat higher 147Sm/144Nd values and lower 143Nd/144Nd values, and the Nd isotopes of granites are similar to things of Beishan area granites.According to lithological characteristics and formation environment, the authors hold that the Dongqiyishan alkali feldspar granite was formed by the magma derived from partial melting of the upper crust through violent differentiation evolution in the late Yanshanian extrusion-tension environment.First, the alkali-feldspar granite porphyry was formed and constituted the exterior facies of the porphyraceous alkali feldspar granite.The formation environment of the alkali-feldspar porphyraceous granite was relatively closed; it was formed through the further enrichment of the volatile components and rare elements and a slow process of crystallization differentiation.Therefore, the self-metasomatism produced by the residual fluid became more developed, resulted in more close connection of lepidolite mineralization and secondary albitization and silicification to niobium-tantalum, tungsten, tin, rubidium and other rare metals mineralization The results obtained by the authors have some guiding significance in the study of Mesozoic granite-related metal ores of Yanshanian period, especially in the prospecting for niobium-tantalum, tungsten, tin, rubidium and other rare metal deposits.关键词
碱长花岗岩/稀有金属/地球化学/同位素/燕山期/东七一山Key words
alkali feldspar granite/ rare metals/ geochemistry/ isotope/ Yanshanian/ Dongqiyishan分类
天文与地球科学引用本文复制引用
吕博,杨岳清,孟贵祥,严加永,赵金花,王守光,贾玲珑,彭润民..内蒙古东七一山碱长花岗岩的地球化学特征和成因[J].岩石矿物学杂志,2011,30(3):543-552,10.基金项目
国家科技支撑计划课题资助项目(2006BAB01A09) （2006BAB01A09）
