The Stable Field of Non-stoichiometric Clinopyroxenes under the Ambient Pressure

常压下非化学计量单斜辉石的稳定场

• 批准号: 10640471
• 负责人: MARUMO Fumiyuki
• 金额: $ 1.09万
• 依托单位: Nihon University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640471/
• 关键词: non-stoichiometric clinopyroxene; pyroxene; diopside; esseneite; 非化学量論輝石; エッセネアイト; マグネタイト; 単斜輝石

A study was carried out on the phase relation in an esseneite-rich region of the pseudo-three-components system diopside(Di)-esseneite(Es)-anorthite(An) under the ambient pressure at several compositions in order to determine the stable field of non-stoichiometric clinopyroxenes. At the composition of Di_<23>Es_<53>An_<24>, crystals of diopside solid-solutions crystallized at 1350 and 1325℃, whereas non-stoichiometric clinopyroxenes appeared at 1300, 1275 and 1250℃. The chemical compositions determined with EPMA are Ca_<0.99>(Al_<0.30>Mg_<0.19>Fe_<0.48>)(Al_<0.22>Si_<1.78>)O_6, Ca_<0.99>(Mg_<0.39>Fe_<0.61>)(Al_<0.43>Si_<1.41>Fe_<0.16>)O_6, Ca_<0.75>(Mg_<0.02>Al_<0.87>Fe_<0.15>)(Al_<0.45>Si_<1.55>)O_6, Ca_<0.74>(Mg_<0.02>Al_<0.80>Fe_<0.17>)(Al_<0.44>Si_<1.56>)O_6 and Ca_<0.73>(Mg_<0.03>Al_<0.79>Fe_<0.19>)(Al_<0.47>Si_<1.53>)O_6 for the products obtained at 1350, 1325, 1300, 1275 and 1250℃, respectively. The phase relations were also explored on the join Di-Es at the compositions Di_<20> … More Es_<80>, Di_<30>Es_<70> and Di_<40>Es_<60>. At 1350℃ stoichiometric crystals of diopside solid-solutions coexist with liquids at all the compositions, while non-stoichiometric clinopyroxenes crystallize at 1325℃ and the lower temperatures. In the case of the composition Di_<30>Es_<70>, chemical analyses gave the formulae Ca_<0.98>(Mg_<0.48>Al_<0.26>Fe_<0.29>)(Al_<0.57>Si_<1.43>)O_6, Ca_<0.75>(Mg_<0.03>Al_<0.81>Fe_<0.16>)(Al_<0.48>Si_<1.52>)O_6, Ca_<0.74>(Mg_<0.02>Al_<0.82>Fe_<0.15>)(Al_<0.48>Si_<1.52>)O_6 and Ca_<0.74>(Mg_<0.04>Al_<0.84>Fe_<0.19>)(Al_<0.44>Si_<1.56>)O_6 for the clinopyroxenes crystallized at 1350, 1325, 1300 and 1250℃, respectively. The differences are quite small between chemical compositions of non-stoichiometric clinopyroxenes obtained at different temperatures from waw materials with different compositions. The non-stoichiometric clinopyroxenes extremely rich in Al and poor in Mg. On the other hand, the stoichiometric clinopyroxenes contain fairly large amounts of Mg and are rich in Fe. With this investigation, the non-stoichiometric clinopyroxenes are shown not to be unique products under high pressure conditions. Less

为了确定非化学计量单斜辉石的稳定场，研究了常压下透辉石（Di）-钠长石（Es）-钙长石（An）假三元体系在富钠长石区的相关系。在Di_<23>Es_<53>An_<24>组成下，透辉石固溶体晶体在1350和1325℃结晶，非化学计量单斜辉石晶体在1300、1275和1250℃结晶。用电子探针分析了在1350、1325、1300、1275和1250℃下得到的产物的化学组成分别为Ca_<0.99>（Al_<0.30>Mg_<0.19>Fe_<0.48>）（Al_ Si<0.22>_）<1.78>O_6<0.99><0.39><0.61><0.43><1.41><0.16>、Ca_<0.75>（<0.02>Mg_ Fe<0.87>_<0.15>）（Al_<0.45>Si_<1.55>）O_6、Ca_<0.74>（Mg_<0.02>Al_<0.80>Fe_<0.17>）（Al_<0.44>Si_<1.56>）O_6和Ca_<0.73>（Mg_<0.03>Al_<0.79>Fe_<0.19>）（Al_<0.47>Si_<1.53>）O_6。还探讨了在组成Di_（1-x）处Di-Es相连接处的相关系。<20> ...更多信息 Es_<80>、Di_<30>Es_<70>和Di_<40>Es_<60>。在1350℃时，透辉石固溶体的化学计量晶体与液体共存，而非化学计量单斜辉石在1325℃及更低温度下结晶。在Di_Es_3组成的情况下<30>，<70>化学分析分别给出了在1350、1325、1300和1250℃结晶的单斜辉石的化学式Ca_<0.98>（<0.48><0.26><0.29><0.57><1.43><0.75>Mg_Al_Fe_3<0.03><0.81><0.16>）（Al_Si_3<0.48><1.52>）O_6、Ca_<0.74>（<0.02>Mg_Al_Fe_3<0.82><0.15>）（<0.48>Al_Si_3<1.52>）O_6和Ca_<0.74>（<0.04>Mg_Al_Fe_3<0.84><0.19>）（<0.44>Al_Si_3<1.56>）O_6。不同组成的原料在不同温度下得到的非化学计量单斜辉石的化学组成差别很小。非化学计量单斜辉石富Al贫Mg。另一方面，化学计量的单斜辉石含有相当大量的Mg和富Fe。研究结果表明，非化学计量比单斜辉石在高压条件下不是唯一的产物。少

项目成果

M.Okui, Y.Kamimura, S.Hatano, M.Ohta & F.Marumo: "Synthesis of Non-Stoichiometric Clinopyroxenes in the System Diopside-Esseneite under Ambient Pressure."Proceedings of The Institute of Natural Sciences, Nihon University. No.36. 103-107 (2001)

M.奥井、Y.Kamimura、S.Hatano、M.Ohta

M.Okui,Y.Kamimura,S.Hatano,M.Ohta,F.Marumo: "Synthesis of Non-stoichiometric Clinopyroxenes in the System Diopside-Esseneite under Ambient Pressure."Proceedings of The Institute of Natural Sciences, Nihon University. No.36. 103-107 (2001)

M.Okui、Y.Kamimura、S.Hatano、M.Ohta、F.Marumo：“常压下透辉石-钙铝石体系中非化学计量斜辉石的合成”。日本大学自然科学研究所论文集。

M.Okui,Y.Kamimura,S.Hatano,M.Ohta,F.Marumo: "Synthesis of Non-stoichiometric Clinopyroxenes in the System Diopside-Esseneite under Ambient Pressure."Proceedings of The Institute of Natural Sciences,Nihon University. No.36. 103-107 (2001)

M.Okui、Y.Kamimura、S.Hatano、M.Ohta、F.Marumo：“常压下透辉石-钙铝石体系中非化学计量斜辉石的合成”。日本大学自然科学研究所论文集。

M.Okui,H.Sawada,F.Marumo: "Structure refinement of a nonstoichiometric pyroxene synthesized under ambient pressure."Physics and Chemistry of Minerals. 25. 318-322 (1998)

M.Okui、H.Sawada、F.Marumo：“环境压力下合成的非化学计量辉石的结构精炼。”矿物物理和化学。

M.Okui, H.Sawada & F.Marumo: "Structure refinement of a nonstoichiometric pyroxene synthesized under ambient pressure."Physics and Chemistry of Minerals. 25. 318-322 (1998)

奥井M、泽田H