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Geothermal
Geology (Deep Geothermal Systems and Others)
Muraoka,
H., Uchida, T., Sasada, M., Yagi, M., Akaku, K., Sasaki, M., Yasukawa,
K., Miyazaki, S.-I., Doi, N., Saito, S., Sato, K. and Tanaka, S. (1998)
Deep geothermal resources survey program: igneous, metamorphic and hydrothermal
processes in a well encountering 500 oC at 3729 m depth, Kakkonda,
Japan. In: Sasada, M., Doi, N., Muffler, L.J.P. and Hedenquist, J.W.
(eds) Deep Geothermal Systems, Japanese National Project at Kakkonda.
Geothermics, 27, 507-534.
This article summarized the results of the Deep Geothermal Resources
Survey Program performed by NEDO (Entrustment Contract: Japan Metals and
Chemicals Co. Ltd.), in close technical cooperation of the Geological
Survey of Japan. The exploration well WD-1a, a central object of this
program, was drilled in the Kakkonda geothermal field and penetrated part
of an unexposed and still hot neo-granitic pluton "Kakkonda Granite" below
the depth of 2860 m and reached the high temperature more than 500 degree
Celsius at the bottom of the well at the depth of 3729 m. In other words,
this well penetrated a magma chamber in a subsolidus temperature condition
(Subsolidus means the temperature just below the minimum melting temperature
of the granitic system). This article is only part of the results of the
entire project but the project performed the highest temperature record
of geothermal drillings in the world and brought strong impact and valuable
information to the world geothermal community. It demonstrated high potentiality
of Japanese geothermal technology.
Other Articles
Muraoka, H. (1992) A hypothesis on the alternative between thermal conduction
aureole and juvenile brine aureole in the vicinity of magma intrusives.
Jour. Soc. Geotherm. Res. Japan, 14, 47-59 (in Japanese with English abstract).
Muraoka, H. (1993)
Scope of the future geothermal resources in the viewpoint from magma. Chinetsu,
30, 100-126 (in Japanese).
Muraoka, H. , Shigeno, H., Ishido, T. and Uchida, T. (1997)
Scope of modeling of deep geothermal systems in an IEA co-operative
program. Proc. NEDO International Geothermal Symposium, Sendai, 200-207.
Muraoka, H. (1997) Petrochemical profiling of the aureole
of the Kakkonda Granite using cuttings samples along the well WD-1a,
Northeast Japan. Geothermal Resources Council Transactions, 21, 309-316.
Muraoka, H. (1997) Conceptual model for emplacement depth
of magma chambers and genesis of geothermal systems. Proc. 30th Int'l.
Geol. Congr., Beijing, Vol.9, 143-155.
Muraoka, H. and Yano, Y. (1998) Why neo-plutons are deeper
in extension tectonic fields and shallower in contraction tectonic
fields? Proc. 20th NZ Geothermal Workshop 1998, Auckland, 109-114.
Muraoka, H. (1999) Magma-tectonic
background of geothermal systems. Proc. Asian Geothermal Energy Symposium
on Current and Future Geothermal Energy Development in Asia, Subic
Bay, 137-144.
Muraoka, H. and Ohtani, T. (2000) Profiling of the Kakkonda geothermal
system by bulk rock chemistry of the well WD-1a. Rept. Geol. Surv. Japan,
No.284, 33-55 (in Japanese with English abstract).
Last Update: February
8, 2003
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