Chemical and boron isotopic compositions of tourmaline from the   Paleoproterozoic Houxianyu borate deposit, NE China: Implications for   the origin of borate deposit

doi:10.1016/j.jseaes.2014.05.021

CORC > 北京大学 > 地球与空间科学学院

	Chemical and boron isotopic compositions of tourmaline from the Paleoproterozoic Houxianyu borate deposit, NE China: Implications for the origin of borate deposit
	Yan, Xue-long ; Chen, Bin
刊名	journal of asian earth sciences
	2014
关键词	Tourmaline Borate Boron isotope Paleoproterozoic NE China LIAO-JI BELT RARE-EARTH-ELEMENTS PB ZIRCON AGES EASTERN BLOCK FLUID EVOLUTION NORTHEAST CHINA VOLCANIC-ROCKS JIAOBEI MASSIF ICP-MS CRATON
DOI	10.1016/j.jseaes.2014.05.021
英文摘要	The Houxianyu borate deposit in northeastern China is one of the largest boron sources of China, hosted mainly in the Paleoproterozoic meta-volcanic and sedimentary rocks (known as the Liaohe Group) that are characterized by high boron concentrations. The borate ore-body has intimate spatial relationship with the Mg-rich carbonates/silicates of the Group, with fine-grained gneisses (meta-felsic volcanic rocks) as main country rocks. The presence of abundant tourmalinites and tourmaline-rich quartz veins in the borate orebody provides an opportunity to study the origin of boron, the nature of ore-forming fluids, and possible mineralization mechanism. We report the chemical and boron isotopic compositions of tourmalines from the tourmaline-rich rocks in the borate deposit and from the tourmaline-bearing fine-grained gneisses. Tourmalines from the fine-grained gneisses are chemically homogeneous, showing relatively high Fe and Na and low Mg, with delta B-11 values in a narrow range from +1.22 parts per thousand to +2.63 parts per thousand. Tourmalines from the tourmaline-rich rocks, however, commonly show compositional zoning, with an irregular detrital core and a euhedral overgrowth, and have significantly higher Mg, REE (and more pronounced positive Eu anomalies), V (229-1852 ppm) and Sr (208-1191 ppm) than those from the fine-grained gneisses. They show varied B isotope values ranging from +4.51 parts per thousand to +12.43 parts per thousand, which plot intermediate between those of the terrigenous sediments and arc rocks with low boron isotope values (as represented by the delta B-11 = +1.22 parts per thousand to +2.63 parts per thousand of the fine-grained gneisses of this study) and those of marine carbonates and evaporates with high boron isotope values. In addition, the rim of the zoned tourmaline shows notably higher Mg, Ti, V, Sn, and Pb, and REE (particularly LREEs), but lower Fe, Co, Cr, Ni, Zn, Mn, and lower delta B-11 values than the core. These data suggest that (1) the sources of boron of the borate ore-body are mainly the Paleoproterozoic meta-volcanic and sedimentary rocks, and (2) the ore-forming fluids should be the high temperature metamorphic fluids related to the amphibolite-facies metamorphism of the Paleoproterozoic foldbelt, which leach boron from the boron-rich meta-volcanic and sedimentary rocks of the Liaohe Group, and the boron-rich metamorphic fluids subsequently interacted with the marine Mg-rich carbonates and evaporates, forming borate deposit, the tourmaline overgrowth in the rim and the tourmaline-rich rocks. (C) 2014 Elsevier Ltd. All rights reserved.; Geosciences, Multidisciplinary; SCI(E); 0; ARTICLE; binchen@pku.edu.cn; ,SI; 252-266; 94
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/155379]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Yan, Xue-long,Chen, Bin. Chemical and boron isotopic compositions of tourmaline from the Paleoproterozoic Houxianyu borate deposit, NE China: Implications for the origin of borate deposit[J]. journal of asian earth sciences,2014.
APA	Yan, Xue-long,&Chen, Bin.(2014).Chemical and boron isotopic compositions of tourmaline from the Paleoproterozoic Houxianyu borate deposit, NE China: Implications for the origin of borate deposit.journal of asian earth sciences.
MLA	Yan, Xue-long,et al."Chemical and boron isotopic compositions of tourmaline from the Paleoproterozoic Houxianyu borate deposit, NE China: Implications for the origin of borate deposit".journal of asian earth sciences (2014).