著者

浜根 大輔

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.44, no.1, pp.57-59, 2015 (Released:2015-03-05)

参考文献数

6

著者

北風 嵐 小松 隆一

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.45, no.5, pp.133-137, 2016 (Released:2016-11-02)

参考文献数

14

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Ni-rich horomanite is found from the chalcopyrite-bearing (1.0-1.5 mode%) layer in the Kouyama gabbroic body, Hagi city, Yamaguchi Prefecture, western Japan and as second occurrence in the world.  It occurs as inclusions in chalcopyrite interspaced with silicate minerals, vanadium-bearing magnetite and ilmenite. It is often associated with siegenite and is secondarily replaced by violarite. Chalcopyrite associating with Ni-rich horomanite commonly shows the polysynthetic twin.  Analytical data for horomanite obtained by EPMA are Cu: 0.56-2.19, Fe: 23.01-25.32, Ni: 37.45-41.35, Co: 1.56-4.03 and S: 32.85-33.32 wt%. Their variations are small for inner grain or another grain. The atomic ratio of (Cu + Fe + Ni + Co): S correlates well with ideal formula of 9:8 for horomanite. In addition, Ni content in metal ratio for (Cu + Co): Fe: Ni (at%) ranges from 52 to 59 and is Ni-rich than that of original horomanite from the Horoman peridotite. Horomanite might be considered to be continuous solid solution ranging from 3.0 to 5.5 in terms of Ni(+Co) content. Therefore, general formula for horomanite is thought to be (Fe + Cu)6 − x(Ni + Co)3 + xS8(0 < x < 2.5).

著者

佐脇 貴幸

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.32, no.1, pp.23-41, 2003 (Released:2008-04-21)

参考文献数

155

被引用文献数

2 7

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Crustal fluids are sometimes trapped in minerals during crystal growth or healing of microcracks. The fluids trapped and completely sealed in minerals are called “fluid inclusions”. A fluid inclusion is considered to be a small closed system after trapping, and the conditions of temperature, pressure and chemistry at fluid-trapping can be reproduced in fluid inclusions by various analytical systems. Microthermometry, chemical analyses and observation on occurrence of fluid inclusions are available for exploration of ore deposits, geothermal and petroleum resources, for studies on thermal histories of sedimentary rocks, for elucidation of origins, formation conditions and processes of igneous and metamorphic rocks, for analyses of paleo-stresses and paleo-climates, and consideration on astronomical events.

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.45, no.1, pp.43-44, 2016 (Released:2016-03-03)

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「地球温暖化シミュレーション 地質時代の炭素循環」「隕石でわかる宇宙惑星科学」

著者

宮脇 律郎

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.36, no.6, pp.182-183, 2007 (Released:2008-03-27)

参考文献数

9

著者

山中 高光

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.32, no.3, pp.109-111, 2003 (Released:2008-04-21)

著者

坂野 靖行

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.36, no.6, pp.187-189, 2007 (Released:2008-03-27)

参考文献数

6

著者

山田 涼子 佐藤 博明

出版者

一般社団法人 日本鉱物科学会

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.93, no.8, pp.279-290, 1998 (Released:2006-08-22)

参考文献数

34

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Takamatsu crater has been identified and named by Kono et al., (1994), based on the presence of a concentric gravity low in the southern part of Takamatsu Plain, northeast Shikoku, Japan. The crater is 1∼2 km deep and ca. 4 km across, and buried under the Miocene volcanic formation and alluvium deposit. Both impact and volcanic origins have been proposed for the crater, but remained unresolved. We searched for the evidence of impact origin of the Takamatsu crater, such as shock metamorphic features of minerals, variable and extraordinarily high contents of SiO2, FeO, and NiO, together with low Na2O content of fresh glass in the Miocene deposit. The glass fragments in the pyroclastic flow deposit in the southern part of the Takamatsu crater are characterized by xenocrysts of quartz and feldspar and lack of idiomorphic phenocrysts. We did not find evidence for shock metamorphism in the minerals. The glass shows heterogeneous appearence with variable red tints and high vesicularity under the microscope, somewhat similar to the suevite of Ries crater. The glass of the Takamatsu crater, however, shows uniform and rhyolitic chemical composition, which is common for the calc-alkalic volcanics of the Miocene Setouchi volcanic suite. Furthermore, chemical composition of the glass is almost identical to those of welded tuff blocks and bulk matrix of the pyroclastic flow deposit, indicating that the glass fragments are of volcanic origin. The glass and associated rhyolite are dated by K-Ar method at around 14 Ma, which coincides with the age of the Setouchi volcanic activity. Although deep drilling has not been carried out for determining the subsurface structure, present analytical results argued for cauldron origin of the Takamatsu crater.

著者

水上 知行

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.31, no.2, pp.87-96, 2001 (Released:2008-05-08)

参考文献数

25

被引用文献数

3 4

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The Sugashima ultramafic mass is one of the largest ultramafic bodies in the Mikabu belt, and is composed of a hornblende-poor part (Unit I) and a hornblende-rich part (Unit II). Unit I is a layered complex with laminar and convoluted structures probably formed as a crystal mush. Detailed petrographic studies reveal that orthopyroxene exists in almost all the rock types forming the igneous layering of Unit I: dunite, plagioclase wehrlite and olivine gabbro. Orthopyroxene crystals commonly occur adjacent to olivine crystals and locally show poikilitic textures enclosing olivine grains with rounded or irregular shapes, indicating their peritectic growth from a basaltic magma at a pressure lower than 0.9 GPa.

著者

谷口 宏充

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.29, no.3, pp.97-109, 2000 (Released:2008-08-30)

参考文献数

63

被引用文献数

1

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In the past several decades a significant number of research papers has been appeared on the international journals of earth sciences that has referred to the viscous behavior of magmatic silicate melts. It is, obviously, the reflection of importance of viscosity on the magmatic process such as magma generation and volcanic eruption and of importance for the understanding of early history of the Earth. Contrary to the importance, the theoretical background of viscosity of a magmatic silicate melt has not been understood well. This review paper is concerned with the introduction to some basic knowledges and two representative theories on the viscosity of magmatic silicate melts. The first part deals with the definition, methods of viscosity measurement and the effects of parameters that govern the viscous behavior. The second part deals with the free volume theory, which was the early theoretical background for the understanding of viscous behavior of a liquid. This theory emphasizes the importance of free space in a magmatic silicate melt. The third part deals with the configurational entropy theory, which is the theory in much fashion in magma science. The characters of this theory are the combination of thermodynamic data with the viscosity, and the emphasis of the number of configurational state attainable in a magmatic silicate melt. This theory succeeded in the quantitative interpretation of the change of viscosity with temperature and chemical composition.

著者

榊原 正幸 上原 誠一郎

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.35, no.1, pp.3-10, 2006 (Released:2006-03-01)

参考文献数

29

被引用文献数

2 1

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The term asbestos is a generic designation given to six types of naturally occurring mineral fibers that are or have been used in commercial products. These fibers belong to two mineral groups: serpentines and amphiboles. The serpentine group contains a single asbestiform variety: chrysotile. The amphibole group contains five asbestiform amphibole varieties: anthophyllite, grunerite (amosite), riebeckite (crocidolite), tremolite and actinolite.     These fibrous minerals share several properties which qualify them as asbestiform fibers. They are bundles of fibers which can be easily cleaved into thinner fibers. Several properties that make asbestos so versatile and cost effective are high tensile strength, chemical and thermal stability, high flexibility, and low electrical conductivity.     Asbestos fibers have been used in a broad variety of industrial application; some 3000 applications such as roofing products, gaskets, and friction products. 80% of imported asbestos is used for cement products such as asbestos boards and slates which are used for building materials, 7% for friction materials, and less than 3% for asbestos textile. Nearly all of the asbestos produced worldwide is chrysotile. Historically, chrysotile has accounted for more than 90% of the world’s asbestos production, and it presently accounts for over 99% of the world production. Two types of amphiboles, commonly designated as amosite and crocidolite are no longer mined. With the onset of the health issues concerning asbestos in the late 1960s and early 1970s, world production and consumption began to decline during the 1980s. Japan used approximately 6.7 million tons between 1974 and 2004. About 67% of this amount was used since 1930.     The relationship between workplace exposure to airborne asbestos fibers and respiratory diseases is one of the most widely studied subjects of modern epidemiology. The research efforts resulted in significant consensus that asbestos fibers can be associated with diseases of asbestosis, lung cancer and mesothelioma. Its carcinogenic nature, an overall lack of knowledge of minimum safe exposure levels, and the long latency for the development of lung cancer and mesothelioma are the main contributing factors to these controversies.