著者

W. G. ERNST

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.106, no.5, pp.735-738, 1997-10-25 (Released:2009-11-12)

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The strategic justification for supporting scientific activities has largely depending on the understanding that research provided both national security in a time of global hostility involving the improvement of the economy, greater social equity, better health, better race relations, and enhancement of environmental quality, and widespread health benefits. In terms of curriculum in the Earth Sciences, the important point here is that study courses must evolve to accommodate the changing, enlarging body of knowledge as well as the ultimate career needs of the future degree holders. Growing subdisciplines needed in America include hydrology, hydrogeology, neotectonics, continental margin oceanography, engineering geology, geologic hazards, environmental science, aqueous geochemistry, and material sciences. Metamorphic petrologists are especially well-equipped with the fundamental knowledge from physics and chemistry as well as geology to treat the problems society wishes to address and solve. The situation provides us with a natural advantage, but to realize it, we must move our emphasis away from the traditional topics of metamorphic petrology.

著者

日本地学史編纂委員会

出版者

東京地学協会

雑誌

地学雑誌

巻号頁・発行日

vol.110, no.3, 2001

著者

加藤 鉄之助

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.25, no.11, pp.755-768_1, 1913-11-15 (Released:2010-10-13)

著者

代田 寧 大場 武 谷口 無我 十河 孝夫 原田 昌武

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.130, no.6, pp.783-796, 2021-12-25 (Released:2022-01-28)

参考文献数

24

被引用文献数

2 2

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Earthquake swarms have occurred with volcanism repeatedly at Hakone volcano in Kanagawa prefecture, Japan. In 2015, a phreatic eruption took place about two months after the start of an earthquake swarm. Hakone volcano is a popular tourist destination. If it is possible to forecast at the early stages of an earthquake swarm whether or not an eruption will occur, the forecast could contribute to preventing disasters involving tourists. At Hakone volcano, increases in the ratio of components (CO2/H2S) contained in the volcanic gas from fumaroles were observed in synchronization with earthquake swarms and ground deformation in 2013 and 2015. Similar increases in CO2/H2S ratio were also observed in 2017 and 2019, although the increases in the CO2/H2S ratio in 2017 and 2019 were not as sharp as those in 2013 and 2015. Furthermore, the maximum values of the CO2/H2S ratio in 2017 and 2019 were lower than the values in 2013 and 2015. These differences in the CO2/H2S ratio may be related to the limited and smaller scale of volcanic activity in 2017 and 2019 relative to 2013 and 2015. Another explanation for the difference is a possible irreversible change in the underground structure of the Owakudani area, which is a geothermal area around Hakone volcano, because the phreatic eruption took place in the Owakudani area in 2015. During all four seismically active periods in 2013, 2015, 2017, and 2019, the CO2/H2S ratio decreased simultaneously with decreases in the number of volcanic earthquakes. The lower limit of CO2/H2S ratios after the peak of the CO2/H2S ratio time series was about 20 in all periods. This implies that subsequent unrest would not start until the CO2/H2S ratio drops to about 20. The CO2/H2S ratio might be an effective tool for forecasting activity at Hakone volcano. During the active periods in 2013, 2015, 2017, and 2019, extensions of the baseline across Hakone volcano were observed by GNSS with increases in the CO2/H2S ratio. A good correlation was found between the extensional velocity of the baseline length and the increasing rate of the CO2/H2S ratio. These variations could be examined at the early stage of unrest. The findings argue that the CO2/H2S ratio is a promising tool for predicting and evaluating volcanic activity at Hakone volcano.

著者

宮田 雄史

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.2, pp.275-288, 2022-04-25 (Released:2022-05-13)

参考文献数

20

被引用文献数

2

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Gems must meet three requirements: be beautiful, be durable, and be rare. The concept beauty depends on personal values. It is, therefore, not something that is objective and separate from human society. Gems have relationships with society and have requirements. That is, it must be determined whether a gem is genuine or fake. Gems are essentially natural materials. They are generally minerals that are naturally occurring solids formed by geological processes. However, gems have a cultural aspect depending on how they are used. In a historical review, how these two aspects of gems have become the subject of scholarship is briefly elucidated. Currently, artificial gem materials are classified according to their growth history, and whether they are synthetic, man-made, imitations or composites. The task of defining these categories, in addition to natural gems and treated gems, is gem identification, which is based on gem variety, genesis (natural or artificial), treatments applied, (quality) origin (locality) and individual recognition. The development and current status of gemology is reviewed from the viewpoint of mineralogy.

著者

赤井 純治

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.2, pp.213-233, 2022-04-25 (Released:2022-05-13)

参考文献数

62

被引用文献数

2

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One of the most significant developing fields in mineralogy during the last quarter century involves interactions between microbes and minerals in the environment. A mineral evolution has been suggested. The fundamentals of biominerals, interactions between biosphere and minerals, and expanding knowledge of the biosphere are presented. Interactions between minerals and microbes are closely related to the evolution of the Earth's surface environment, and they suggest keys for solving environmental problems on the Earth. They are also related to the search for extraterrestrial life. This review sketches a brief history of mineralogy, referring to TEM methods, concerning regularity, irregularity, and interactions of minerals.

著者

土`山 明 松野 淳也

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.2, pp.193-211, 2022-04-25 (Released:2022-05-13)

参考文献数

32

被引用文献数

2

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Chondritic-porous interplanetary dust particles (CP IDPs) originating from comet and carbonaceous chondrites of asteroids are primitive materials in the solar system. This paper reviews our recent research by mineralogical approach on the primitive materials, which include reproduction experiments of glass with embedded metal and sulfide (GEMS) in CP IDPs, detailed three-dimensional structures of GEMS, and discoveries of ultra-porous lithology as a “fossil of ice” in primitive carbonaceous chondrites and CO2-rich fluid inclusions in calcites of an aqueously-altered carbonaceous chondrite based on multi-scale three-dimensional observations. From the results, together with recent dynamic models of solar system formation, a new united model of the formation and evolution of primitive materials in the solar system is proposed as a working hypothesis. In this model, GEMS or GEMS-like materials corresponding to matrices of carbonaceous chondrites form due to the evaporation of precursors followed by condensation and chondrules due to melting followed by solidification in the highest temperature and moderately-high temperature regions, respectively, through a single local heating event. These local events occur at different distances from the sun and the high-temperature products were aggregated into comets and parent bodies of carbonaceous chondrites with ice and organic materials.

著者

大谷 栄治

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.2, pp.179-192, 2022-04-25 (Released:2022-05-13)

参考文献数

63

被引用文献数

2

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Various phase transitions occur in the Earth's interior. They cause discontinuities in seismic velocity and density profiles. The 410 km and 660 km discontinuities are explained by the olivine–wadsleyite transformation and the decomposition of ringwoodite into ferropericlase and bridgmanite, respectively. The major transitions in the lower mantle are the spin transition in mantle minerals containing ferric and ferrous irons, the post-perovskite transition of bridgmanite, i.e., the transformation of bridgmanite into a post-perovskite phase with a CaIrO3 structure. The former transition may occur at the shallow lower mantle, whereas the latter transition occurs at the bottom of the lower mantle, which may correspond to the D″ layer at the core–mantle boundary. There are several important seismic velocity anomalies. These include low-velocity anomalies associated with hot rising mantle plumes and oceanic ridge areas, and high-velocity anomalies associated with cold slab subduction. Ocean water is returned into the mantle by hydrous minerals stored in the slabs. Some hydrous minerals such as the solid solution of hydrous phase δ and phase H, AlOOH-MgSiO4H2 are stable along the normal geotherm to the core–mantle boundary, and bring water into the base of the lower mantle. Another interesting region is located at the base of the lower mantle. These anomalies are called the Large Low Shear Velocity Provinces (LLSVP) and the Ultra-Low Velocity Zones (ULVZ). An LLSVP is considered to be a region with iron enrichment. This region may be caused by accumulations of the high-pressure hydrous phases. A ULVZ with very low compressional and shear velocities and high densities is observed at the core–mantle boundary. This region may contain dense iron rich melts. The Earth's core is composed of a molten outer core and a solid inner core. It consists mainly of iron–nickel alloy with small amounts of light elements, such as Si, O, S, C and H. The inner core is considered to be composed of an hcp phase. However, some enigmatic properties of the inner core, such as low shear velocity and anisotropy, may not be explained only by this phase. Some experimental and theoretical studies suggest the existence of a bcc phase at a high temperature region approaching the melting temperature. Therefore, the inner core may be composed of a bcc phase or a mixture of hcp and bcc (or B2 phase which is an ordered form of the bcc structure). Further studies are necessary to achieve a better understanding of the Earth's core.

著者

宮脇 律郎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.2, pp.129-132, 2022-04-25 (Released:2022-05-13)

参考文献数

11

著者

Ritsuro MIYAWAKI

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.2, pp.125-128, 2022-04-25 (Released:2022-05-13)

参考文献数

11

著者

上野 勝美 Tamara I. NEMYROVSKA

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.117, no.5, pp.919-932, 2008-10-25 (Released:2010-04-27)

参考文献数

22

被引用文献数

7 8

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To better understand and update knowledge of the stratigraphy and foraminiferal and conodont faunal successions of Bashkirian-Moscovian (Pennsylvanian/Upper Carboniferous) boundary intervals in the Donets Basin of Ukraine, we studied the C21 to C26 suites (Limestones F to L) of the following eight stratigraphic sections located in the eastern part of the basin. These are the Karaguz, Volnukhino, Kriven'ky Yar, Rudnya, Zolotaya, and Malonikolaevka sections in Lugansk county and the Soroch'ya and Kholodnaya sections in Donetsk county. Among them, the Malonikolaevka section, which is located about 35km southwest of Lugansk and is documented for the first time in this study, provides important data on the faunal successions of the Bashkirian-Moscovian boundary interval, ranging from Limestones I2 to K3. Both the conodont and fusuline faunas record the appearances in the basal part of the C25 (K) Suite of several new taxa that are more characteristic of the early Moscovian. These forms include Declinognathodus donetzianus at the top of K1 in conodonts and Eofusulina triangula, E. trianguliformis, and a large Neostaffella species (N. vozhgalica) at K2 in fusulines. Thus, the K1-K2 interval is very promising as the potential position of the formal Bashkirian-Moscovian boundary in the Donets Basin. The data from the Malonikolaevka section, together with those from other sections in the present study, would be significant for future investigations of the Task Group to establish a GSSP close to the existing Bashkirian-Moscovian Boundary organized in IUGS Subcommission on Carboniferous Stratigraphy (SCCS).

著者

柴田 賢

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.94, no.7, pp.682-686, 1986-01-25 (Released:2009-11-12)

参考文献数

10

著者

日野 文雄

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.50, no.2, pp.77-90, 1938-02-15 (Released:2010-10-13)

参考文献数

20

著者

日野 文雄

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.50, no.1, pp.19-30, 1938-01-15 (Released:2010-10-13)

著者

金田 楢太郎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.5, no.4, pp.189-194, 1893-04-25 (Released:2010-10-13)

著者

David Simon

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.65, no.2, pp.100-105, 1956-06-30 (Released:2009-11-12)

参考文献数

1

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ソヴィエットの樺太および千島列島占領は, 以前の日本語の地名のあらゆる痕跡を拭い去つてしまつた。こんにちでは, 日本語の影響をほのめかす地名は, 一つとて存在しない。残されている地名はたゞアイズ語に起源をもつ, 若干のものであり, それらでさえも, ロシア当局によつて, 入念に篩にかけられた。ここに挙げたものは日本語の照合名, 地理的経緯度および地名起源の簡単な説明を加えた, 100の選択されたロシア語の地名である。

著者

中禮正明

出版者

東京地学協会

雑誌

地学雑誌

巻号頁・発行日

vol.111, no.2, 2002

著者

山本 真也 中村 高志 芹澤 如比古 中村 誠司 安田 泰輔 内山 高

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.129, no.5, pp.665-676, 2020-10-25 (Released:2020-11-13)

参考文献数

40

被引用文献数

3 5

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Lake bottom springs play an important role in maintaining water quality in the Fuji Five Lakes. However, the sources of these springs and the hydrological delivery mechanisms have yet to be identified. To determine the sources of spring water of Lake Kawaguchi, samples were collected directly from lake bottom springs, and oxygen and hydrogen stable isotope ratios were obtained, along with vanadium concentrations. Visual observations and water-quality analyses of the samples reveal that cold and oxygen-rich water is discharged from the lake floor, which is covered by gravel with diameters of 10-50 cm over an area of approximately 9 m (east–west) by about 13 m (north–south). The water temperature of the springs remained relatively constant at around 11.3°C during the stratified period in 2016; however, the temperature fluctuated significantly in 2017, even during the stratified period, suggesting a temporary decrease or stoppage of water being discharged from springs into the lake. Oxygen and hydrogen stable isotopic ratios of lake bottom springs were determined to be higher than those of groundwater in the southern part of Lake Kawaguchi; however, they displayed values close to those of groundwater in the northern part of Lake Kawaguchi, suggesting that spring water primarily originated from groundwater in the Misaka Mountains.

著者

高野 修 西村 瑞恵 藤井 哲哉 佐伯 龍男

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.118, no.5, pp.776-792, 2009-10-25 (Released:2010-03-19)

参考文献数

28

被引用文献数

21 18

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Since previous research revealed that most of the methane hydrates in the eastern Nankai Trough area occur in matrix pores of turbidite sandstones, the facies distribution of turbidite sandstones may be one of the important keys to evaluate the distributions and actual volume of methane hydrates in the eastern Nankai Trough area. This paper attempts to reconstruct depositional processes of submarine-fan turbidites, and examines the relationship between turbidite facies distributions and bottom simulating reflector (BSR) occurrence as a proxy of methane hydrate using sedimentologic and sequence stratigraphic methodology. First, 2D/3D seismic survey data and well data including cores and logs were used to identify turbidite facies, seismic facies, and depositional sequences. The targeted Plio-Pleistocene Kakegawa and Ogasa Groups can be divided into 17 depositional sequences, and include six seismic facies indicating submarine-fan elements and surrounding slope to basin-floor environments. Next, facies maps for each depositional sequence unit were created by plotting all information on seismic facies, 3D seismic geomorphology, and well facies data. The obtained facies maps reveal that 11 major submarine canyons functioned as positionally fixed sediment supply systems from main land Japan, along which submarine fans were formed in the forearc basins. Submarine-fan depositional styles changed through Plio-Pleistocene from a braided channel type, through small radial fan, trough-fill fan, and muddy sheet fan types, to a channel-levee system type. Finally, the facies maps of each depositional sequence were overlaid with the BSR distribution. The overlaid maps indicate that the BSRs occur on feeder channels, distributary channels, and proximal lobes of submarine fans, suggesting that methane hydrates selectively occur in coarser grained portions of a submarine fan. Because the lower part of the Kakegawa Group is mainly composed of braided channel-type submarine fan turbidites, the lower Kakegawa horizon serves one of the major horizons bearing methane hydrates in the eastern Nankai Trough area.

著者

矢島道子

出版者

東京地学協会

雑誌

地学雑誌

巻号頁・発行日

vol.114, no.4, 2005