The four major geothermal power plants - Otake, Hatchobaru, Takigami and Sugawara -, are located in the Kuju geothermal district of Oita Prefecture and have a total capacity of 157 MW. Geothermal reservoirs have formed in the margins of uplifted zones and, after the Middle Pleistocene, have been associated with volcanism. The Japan, Oil, Gas and Metals National Corporation (JOGMEC) conducted helicopter-borne time domain electromagnetic survey (HELITEM) and picked up low resistivity anomalies due to argillic alteration zones which indicated impermeable cap rock over geothermal reservoir in 2014. An alteration survey was performed of the low resistivity anomalies for the purpose of investigating argillic alteration zones and evaluating the geothermal potential. Promising alteration zones were selected in the Nanbu-Mizuwake Pass, Otake-Hatchobaru, Sugawara, Nanbu-Waitasan, Makinoto Pass and others. The alteration minerals are composed of acid to neutral argillic minerals such as pyrophyllite, dickite, kaolinite, halloysite and smectite, which are zonally arranged. The alteration zones were formed by hydrothermal solution, ascending from deep underground to shallow levels along faults. The faults predominantly trend WNW-ESE, ENE-WSW and NW-SE. They tectonically formed under a horizontal and extensional stress field trending N-S. Acid alteration zones, which consist of kaolinite, dickite, alunite and so on, are particularly important from the standpoint of geothermal exploration. That is because they have formed as impermeable clay layer over geothermal reservoirs where hydrothermal solution of high temperature flows convectively along faults. Alteration minerals were identified by FieldSpec4 spectrometer. The probability of visual identification of the absorption spectra was 78.1%, verified by X-ray powder diffraction (XRD) of a part of samples. Some samples, which were composed of acid alteration minerals, were incorrectly identified as smectite or zeolite. The incorrect identification is due to the absorption spectrum (1,920 nm) of water contained in the sample. After this, a method for drying samples should be investigated in order to improve the probability.

Bluish precipitates in association with white precipitates are found on the surface of cave wall at the Yoshimi Hills, Saitama Prefecture, Japan. In the inner part of cave, Neogene Tertiary tuffaceous rocks are exposed without vegetation because the sunlight does not reach. These blue and white precipitates are identified as chalcanthite and gypsum, respectively, using the X-ray powder diffraction. An SEM-EDS analysis shows that the chalcanthites are aggregates of euhedral crystals with nearly pure composition. Thermodynamic calculations indicate that chalcanthite precipitates under oxic copper- and sulfate-rich acidic environment. Taking the topographical and geological settings into consideration, these precipitates are regarded as evaporitic products of copper- and sulfate-rich groundwater which would be formed by the reaction of original vein-type chalcopyrite ore and permeated oxic groundwater of rainwater origin in near-surface shallow groundwater flow system.

Dose equivalent rates at 47 major geologies in Korea were measured indirectly using big rock blocks displaying at “Geologic Time Street of Korea named as Nadeulgil” in Korea Institute of Geoscience and Mineral Resources (KIGAM). The dose equivalent rates at actual geologies were also measured for two sites among these 47 sites. True dose equivalent rates of actual geologic sites were obtained by equation with dose rates on the displaying rocks and the environmental dose at the displaying Geologic Time Street of Korea site of the KIGAM. Obtained results for the Precambrian gneissose area, the Paleozoic calcareous area, the Mesozoic granitic area and the Cenozoic volcanic area are 0.12 ~ 0.21 μSv/h, 0.01 ~ 0.04 μSv/h, 0.09 ~ 0.36 μSv/h and 0.04 ~ 0.06 μSv/h, respectively. The geographic distribution may be useful to evaluate natural environmental radiation in Korea and for tectonic comparison in geology.

The Serra Verde Project, which is one of ion-adsorption type project of rare earth elements (REE) outside of China, has been explored in the northernmost part of Goiás State of Brazil. The REE deposit consists of alluvial sediment and underlying saprolitic weathered granite on the Mesoproterozoic Serra Dourada Granite. This granite consists mainly of biotite granite and muscovite-biotite granite characterized by A-type features. Percentages of ionexchangeable REE in weathered granites and clay-bearing sediments are variable between the samples. This article reviews the previous data of the REE deposit and underlying Serra Dourada Granite and reports results of field investigation on July 2016.

Prices of minerals and energy resources have increased from the winter in 2016, and continued in the past year. However, exploration is not sufficiently active, because the prices are not so high for people working in the field. In spite of low resource prices, some remarkable results have been reported in the explolation and production fields of minerals and energy resources as follows: 1) mineralization of copper (4.59 %) and silver (8 g/t) was gotten in the Cobar superbasin, Australia, 2) an accumulation of oil and gas was found by the exploration well 36/7-4 in the the Cara structure located in the Norwegian North Sea, 3) a deposit of quality oil was discovered by exploration drilling at the onshore Block 10 in Iraq, 4) on May 28, 2017, commercial gas production was commenced from the Layang Field in Block SK10, Malaysia. The geothermal explaration has been carried out actively in reaction to the METI's promotion which started in 2013.

The source rock of Wyoming bentonite is regionally distributed silicic tuff beds intercalated in marine sediments of Cretaceous Epeiric Sea. The tuff beds were subjected to burial diagenesis, and were partly elevated to the surface by Laramide Orogeny in Paleogene. Na-bentonite is predominant, and minable ore reserve is still huge regardless of the mining history of several decades. Compared the Wyoming bentonite with the Tsukinuno bentonite in Japan, we can identify the following common formation conditions: 1) formation of large-scale sedimentary basins behind orogenic belts, 2) supply of voluminous silicic tuff, 3) maximum burial depth is -1,500 to -2,000 meters, which should be shallower than illite/smectite transition levels, 4) exhumation of bentonite deposits by tectonic movement.