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辽宁东部古元古界底部地层(南辽河群)中赋存着大型的硼酸盐矿床,含矿层位中广泛分布含电气石的变粒岩和电英岩。空间上这些含电气石的岩石与硼酸盐有着密切的联系,电气石可以作为区域硼矿找矿的标志。已有研究结果表明,该地区的硼酸盐矿床是变质蒸发岩成因。本研究对该区不同产状的电气石和硼酸盐的地质特征,全岩和矿物成分、硼同位素组成进行了分析。本区的电气石包括层状和脉状两大类,而电气石的富集与硼酸盐关系密切,电英岩往往分布在硼酸盐矿体的上盘。而矿体的下盘一般不产出富电气石的岩石。当长英质脉体穿过硼酸盐矿体时,脉体中往往会富集电气石。含电气石岩石的全岩地球化学分析表明,它们的REE及其他微量元素特征以及相关性关系与周围不含电气石的同类岩石十分相似,反映出一种成因上的联系。本区电气石主要属于镁电气石—铁电气石系列,靠近硼矿体的电气石比远离硼矿体的电气石更加富镁,有着更高的Mg/Fe比值。电气石和硼酸盐的硼同位素成分分析显示出二者在同位素组成上的相似性,前者比后者的δ1lB稍低,这可能是由于热液活动过程中同位素分馏的结果。电气石的硼同位素组成在空间上显示出变化规律:远离硼酸盐矿体的电气石的δ1lB值(-5.2‰～+3.6‰)比矿体附近的电气石低(平均+10.5‰)。以上空间和
Large-scale borate deposits occur in the bottom of the Paleoproterozoic basement (Nanliaohe Group) in eastern Liaoning Province. The ore-bearing beds widely contain tourmaline-bearing granulites and perlite. These tourmaline-bearing rocks are closely related to borate in space, and tourmaline can be used as a symbol for ore prospecting in the area. The existing research results show that the borate deposits in the area are the genesis of metamorphic evaporites. In this study, the geologic characteristics, total rock, mineral composition and boron isotopic composition of tourmaline and borate with different occurrences in this area were analyzed. Tourmaline in this area includes stratiform and veins, and the enrichment of tourmaline is closely related to borate. The electric Yingyan is often distributed on the upper plate of borate ore body. The lower ore body generally does not produce tourmaline-rich rocks. When the long body of British pulse body through the borate ore body, veins tend to enrich tourmaline. The whole rock geochemical analyzes of tourmaline-bearing rocks show that their REE and other trace element characteristics and their correlation are closely related to the similar rocks without tourmaline around them, reflecting a causal relationship. The tourmaline in the area belongs to magnesium tourmaline-iron tourmaline series mainly. The tourmaline close to the boron ore body is more magnesium-rich than the tourmaline far from the boron ore body, and has a higher Mg / Fe ratio. The analysis of boron isotopic composition of tourmaline and borate shows similar isotopic composition, the former is slightly lower than the latter, which may be due to the isotopic fractionation during hydrothermal activity. The composition of boron isotopes in tourmaline shows the variation in space: the δ1lB value (-5.2 ‰ ~ + 3.6 ‰) of tourmaline far away from borate ore body is lower than the tourmaline near the ore body (+10.5 ‰ average). Above space