Development of an internally heated gas apparatus useful for crustal geological problems

各种地质现象（如火山活动、变质作用、地震等）发生在日本的地壳环境下（典型的岛弧）。为了研究这些地质现象，我们开发了一种内部加热的气体设备SMC-5000，它能够产生高达5000巴的压力和1600摄氏度的温度。由于高压气体调节法的严格控制，我们不得不将最大压力从8000降低到5000，不得不放弃自动调压阀。此外，SMC-5000具有出色的压力调节系统，快速淬火装置，精确的温度控制能力和长寿命，可进行长时间（长达一周）的高压实验。利用SMC-5000仪器对北海道Hidaka变质带和秋田县Ichiomegata火山口的下地壳角闪岩进行了熔融实验。用EPMA法测定了熔体的组分、熔体和残留物的组成。并与钙碱性火山岩的岩石学资料进行了比较。在此基础上，提出了日本火山深根区模型。

Various geological phenomena (e.g., volcanic activity, metamorphism, earthquakes, etc) take place under crustal environment beneath Japan (a typical island arc). In order to study these geologic phenomena, we developed an internally heated gass apparatus SMC-5000 which are capable to generate pressure for up to 5000 bars and temperature to 1600 degree centigrade. Due to the very severe control under the High-pressure Gas Regulation Law, we oblighed to lower the maximum pressure from 8000 to 5000 and had to abandone the automatic pressure regulating valve. Otherwise the SMC-5000 was built with excellent pressure regulating system, rapid quenching device, precise temperature controlling capability and long durability for holding very long (up to a week long) high pressure experiments.Using the SMC-5000 apparatus, we conducted melting experiments on some lower crustal amphibolites taken from the Hidaka metamorphic belt in Hokkaido and the Ichiomegata crater in Akita prefecture. The melt frctions as well as the composition of melt and residues were determine with EPMA.The results were then compared with petrologic datra on calc-alkaline volcanic rocks. Based on the comparison, we proposed a model for the deep root zone of Japanese volcanoes.