The upper three-phase region in the system SiO 2 -H 2 O
The upper three-phase region in the system SiO 2 -H 2 O
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DOI：
10.2475/ajs.260.7.501
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发表时间：
1962-09
影响因子：
2.9
通讯作者：
G. Kennedy;G. Wasserburg;H. C. Heard;R. C. Newton
中科院分区：
文献类型：
--
作者：
G. Kennedy;G. Wasserburg;H. C. Heard;R. C. Newton
研究了SiO_2-H_2O系在高温高压下的熔融关系。在1160℃和1500巴的温度下，发现了石英、鳞石英和两种流体之间的四重平衡点。鳞石英、2流体和方石英的第二个四重点估计在1470°C和400巴附近。SiO_2与两种液体相平衡时的凝固点由1720℃降至1130℃(2000bar)。随着压力进一步增加到9700巴，冰点仅额外降低50°C。确定了上三相界面共存流体的组成。单变量平衡曲线的临界点在1080℃和9700巴，成分约为75wt%SiO_2~25wt%H_2O。
Melting relations in the system SiO_2 – H_2O were studied at high temperatures and pressures. A quadruple point for the equilibrium among quartz, tridymite, and 2 fluids was found at 1160° C. and 1500 bars. A second quadruple point for tridymite, 2 fluids, and cristobalite is estimated to be near 1470° C. and 400 bars. The freezing point of SiO_2 in equilibrium with 2 fluid phases is depressed from 1720° C. at one bar to 1130° C. at 2000 bars. This freezing point is diminished by only an additional 50° C. with a further increase in pressure to 9700 bars. The compositions of coexisting fluids along the upper 3-phase boundary have been determined. A critical end point for the univariant equilibrium curve was found at 1080° C. and 9700 bars with a composition of approximately 75 wt% SiO_2 to 25 wt% H_2O.