SUBSOLIDUS RELATIONS IN THE SYSTEM CaCO3-MgCOr-FeCOs BETWEEN 350'AND 550'C
SUBSOLIDUS RELATIONS IN THE SYSTEM CaCO3-MgCOr-FeCOs BETWEEN 350'AND 550'C
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CaCO3-MgCOr-FeCOs 系统在 350 和 550C 之间的固相关系
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
P. E. Rosenberg
中科院分区：
文献类型：
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作者：
P. E. Rosnwneyc;P. E. Rosenberg
在350- 550 ℃温度范围内，用“水热”装置和冷密封压力容器研究了CaCoO-MgCoO-FeCoO 3体系的亚固相线关系。在这些条件下，系统包含一个三相区、三个两相区和三个单相区。两个单相区域的无序，三元固溶体占据一个小字段接近的CaCOa端元和一个狭窄的区域沿着的二元加入MgCOr FeCOa。阳离子有序固溶体的第三个单相区域从白云石沿着连接点caMg（cor）rcaFe（coa）2延伸，在穿过其长度的约三分之二后离开该连接点，并终止于系统的富钙部分，而没有到达二元连接点CacorFeCor。两个无序的固溶体共存的阳离子有序的白云石固溶体中的三相区，位于该系统的Mg-贫的部分。随着温度的升高，白云石固溶体的场进一步向CaFe（Coa）z组分扩展，三相区向二元连接CaCoFecor位移。白云石的铁类似物CaFe（CO2）2在本研究温度范围内处于两相区，但尚未有矿物报道。在三相区合成的白云石中FeCO_3的含量接近天然白云石中FeCO_2的最大含量（~ 35 molTd）。
Subsolidus relations in the system cacorMgcoa-Fecos have been studied in the temperature range 350-550oc at total pressures largely between 2 ar'd 3 kilobars, using "hydrothermal" apparatus and cold seal pressure vessels. Under these conditions, the system contains one three-phase, three two-phase and three one-phase areas. Two one-phase areas of disordered, ternary solid solutions occupy a small field close to the CaCOa end-member and a narrow region along the binary join MgCOrFeCOa. A third one-phase area of cation-ordered solid solutions extends from dolomite along the join caMg(cor)rcaFe(coa)2, departs from this join after traversing approximately two-thirds of its length and terminates in the cacor-rich portion of the system without reaching the binary join CacorFeCor. Two disordered solid solutions coexist with a cation-ordered dolomite solid solution in a three-phase area, located in the Mg-poor portion of the system. with increasing temperature the field of dolomite solid solution extends further toward the composition CaFe(Coa)z and the three-phase area is displaced toward the binary join cacorFecor. The iron analog of dolomite, the compound CaFe(COa)2, which has not been reported as a mineral, Iies in a two-phase area in the temperature range of this study. The FeCOg content of dolomites synthesized from bulk compositions lying within the three-phase area approach the maximum Fecoa content observed in natural dolomites (-35 mole Td.Potental applications of the FeCOs content of natural dolomite to geo-thermometry are suggested.