Shunso Ishihara

The 2009 SGA-Newmont Gold medal is awarded to Dr Shuso Ishihara. The citation was presented by Dr D. Champion. Read Dr Ishiara's acceptance:

Mr. PresidentDear colleague, and ladies and gentlemen.

It is great honor for me to receive the second SGA-New Mont Gold Medal.  would deeply appreciate the recognition of importance of fO2 of granitic magmas for metal concentration.

 was born and raised in eastern suburbs of Hiroshima city, which is located in the center of the largest granitic batholith of Cretaceous-Paleogene age in Japan. In August 6, 1945, I discovered by sight B29 flying over our primary school at 10 minutes after 8 o’clock, then crossing over the Hiroshima city. I saw flashing of A-bomb at 5.2 km distance, few seconds later, I was blown down together with wooden-window frame and ceiling of the primary school. I was the 6th grade at the age of 11. We had to take care of many burned and injured people escaped from the city in that afternoon.

When I entered to the Geological Survey of Japan in April, 1956, peaceful use of atomic energy of the Japanese government was initiated. All the new comers were located in the nuclear-resource section. I found good uraninite concentration in  molybdenite-quartz vein deposits in the largest Mo mine, called Higashiyama. Therefore, I had a good excuse to study molybdenum-deposits, and continued it to PhD.

When I finished to study all the molybdenum-deposits in Japan, I found that quantitatively (i.e., production plus reserves), nearly all the molybdenum deposits occur along the marginal sea side, but tungsten deposits along the Pacific side of the batholith. Molybdenite is falky and very visible often together with wolframite and scheelite. Therefore, in the previous metallogenic maps, the symbol, Mo, is described both in molybdenum and tungsten deposits.

About the host rocks, I also found over 97 % of molybdenum was hosted in granites, nearly 50 % of tungsten is hosted in granites, implying that there must be some difference in the granites from the ore geology view. However, then-current petrologist summary was that they are the same younger-type pink granites. Then, I asked our Research Planning Office in 1969 to do 22 days field work in the Tungsten province. The following modal analyses indicated clear difference in the amount of opaque minerals, which is due to difference in magnetite content.

I have been thinking genesis of the Japanese largest molybdenum deposits, since I visited there in 1957. I have been thinking it even when I was studying Questa Mo deposits in U.S.A. for my Master Degree. I feel “continuous thinking” and/ or “power of thinking” is most essential to have new idea and to make progress in science.

August is a special month for me, because I saw hundreds of burned and injured people escaping by walking from Hiroshima city in the afternoon of August, 6. For this experience, we have been saying “No more Hiroshima” in the past. Now un-necessity of nuclear weapon is more widely recognized, as shown by the U.S. President Obama’s speech in Prague, last April. hope we have a better future in the coming centry..

Thank you for your attention.

Shunso Ishihara

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D. Champion (Geoscience Australia), S. Ishihara (SGA-Newmont Gold Medal), D. Groves (SGA President), J. Pasava (SGA Secretary-General) (Photo by Dr T.J. Beardsmore)