| 矽卡岩矿床中共生单斜辉石一石榴子石特征及其地质意义 |
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| 引用本文：.1990.Characteristics of pargenetic clinopyroxene-garnet pairs in Skarn deposits and their geological significance[J].Mineral Deposits,9(3):195~207 |
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| 中文摘要:通过对我国与Fe，Cu，Mo，W，Sn等主要矿化类型有关的矽忙岩的研究，揭示出不同矿化类型的矽长岩有其特定的共生单斜辉石石榴子石矿物对的成分特征、含铁率比值及其变化规律。依据Fe、Al等组分在共生单斜辉石-石榴子石间的分配，估算各种矿化类型矽卡岩形成的氧逸度和酸度条件，从而划分出我国含矿矽卡岩的氧逸度一酸度相。不同矿化类型的矽卡岩共生单斜辉石-石榴子石的成分特征、形成环境及其变化规律密切联系于其成矿母岩特征，成因类型和成岩条件。 |
| 中文关键词:矽卡岩 单斜辉石 石榴子石 共生 氧逸度 酸度 |
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| Characteristics of pargenetic clinopyroxene-garnet pairs in Skarn deposits and their geological significance |
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| Abstract:Studies of skarns related to Fe, Cu, Mo, W and Sn mineralizations show that the paragenetic clinopyroxene-garnet pairs in skarns of different mineralization types each have their spacific composition and ferriferous ratio. In the direction of Fe-Cu-Mo-W-Sn, the diopside-andradite pair in skarn grades progressively into hedenbergite-grossular pair, accompanied by the increase in Kp value. According to mineral assemblages in skarn and composition of paragenetic pyroxene-garnet pair, oxygen fugacities for the formation of various mineralized karns have been calculated; the formulae for estimating formation acidities of skarns are given on the basis of the camposition of paragenetic clinopyroxene-garnet Pair(see formulae 19.20 in the paper proper). In this way, several oxygen fugacity-acidity phases have been distinguished: high oxygen fugacity-low acidity phase characterized by log fO2≥-20 and pH≥5 or 5.5; intermediate oxygen fugacity-normal aoidity pbase, with logfO2=-20一-23 and pH= 4.5一5.9; low oxygen fugacity-high acidity phase, with log fO2≤-23 and pH=3.5—5.5. Various mineralized skarns were formed under the condition of log fO2=-26一17 and pH=3.5—7.5. The variation trend of oxygen fugacity-acidity during the formation of various types of skarn is discussed; it is also pointed out that deep internal relations in rock-forming and ore-forming geologic-geochemical characteristics and metallogenic physicochemical conditions do exist among magmatism, skarnization, acidic leaching metasomatism and metallization in th8 process of the formation of skarn deposits. |
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