DOCSLIB.ORG

Modern Progress of Geology in Japan 1)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Modern Progress of Geology in Japan 1) Modern Progress of Geology in japan 1) By Teiichi KOBAYASHI In 1920 when the first Pan-Pacific Science Conference was held at Honolulu, there were in Japan only two geological institutes of the universities at Tokyo (founded in 1877) and Sendai (1912). The geological society of Tokyo, Japan (1893) has had no more than 400 members at that time, but now the number is increased as much as about five times. In addition, there are societies and associations of petrologists, mineralogists and economic geologists (founded in 1928, 940 members at present), volcanology (1931, 400), palaeontology (1935, 320), education of earth science (1948, 800), crystallography (1950, 350), mining geologists (1951, 1350), mineralogy (1952, 435), and so forth. They attain more than 15, if those of coal, petroleum and other branches of applied geology are taken into account. The number of geologists and parageologists in addition to mineralogists and palaeontologists is estimated to total no less than 4 , 000. It means the density of more than one geologist in every one hundred sq. km. The rate of increase of geologists is indeed incredibly rapid, if compared to the population which was doubled in Japan in last 55 years. 2) Beside the great expansion of the geological survey of Japan, several institutes were founded for geological researches. As the result of reforming the educational system after the second great war, govermental as well as private colleges and universities and accord- ingly their institutes or departments of geology have been propagated to more than 100. At present journals published from these surveys, institutes and societies far exceed 100. HUJIMOTO's Bibliography of Geology of Japan (1873-1955), 1956, is dealt with 180 journals including a few foreign ones. In Bibliography of Geological Sciences (1945-1955) which was compiled in 1957 as the memorial publication of the 75 th anniversary of the Geological Survey, 196 Japanese journals were referred to. This flood of publications is certainly puzzling workers. Therefore it is strongly required to publish a bibliography annually, as done from the U. S. Geological Survey for North America. ' The below mentioned are expedient compilations for stratigraphers and paleontologists. 1) This is a report of Standing Committee on Geology and Geophysics, Tenth Pacific Science Congress, Hawaii 1961, entitled " The Progress of Geology in Japan during the interval since the First Pacific Science Congress ". but slightly emended and annexed 2 tables. 2) History of the Geological Society of Japan. 60th Anniversary volume, (Japanese), 1953. Address of the Twenty-fifth Anniversary of the Palaeontological Society of Japan. T. KOBAYASHI. Trans. Proc. Pal. Soc. Japan, N. S. No. 41, 1961. 3) More convenient for the foreign reader are the followings : Bibliography of Japanese Palaeontology and Related Sciences, 1940-50. Compiled by R. ENDO. Palaeontological Society of Japan, Special Paper. No. 1, 1951. Titles and Abstracts in Japanese Journal of Geology and Geography, Vols. 1-31, 1922-60, Index to Vols. 1-20 (1922-47), 1955, Vols. 21-25, (1949-54), 1960, Vols. 26-30, (1955-59), 1961 . Titles of geological papers in 62 journals (exclusive of society periodicals and survey publications) are contained in vol. 24 J.J.G.G. (1954) and geological and geographical papers of 96 journals are in vol. 30 of the same journal (1959). 3 210 Teiichi KOBAYASHI Table 1. The Classification of the Cretaceous System in Japan. Lexicon of Stratigraphic Names of Japan, Cenozoic Erathem, Parts 1-3 (A-N), 1954-59, published from Geol. Soc. Japan, (Japanese). Lexique Stratigraphique International, Vol. III, Asie, Fasc. 3a, Japon (K. KANEKO), 3b, Ryukyu (S. HANZAWA). Catalogue of Type Specimens of Fossils in Japan. Compiled by S. HANZAWA, K. ASANO and F. TAKAI. Pal. Soc. Japan, 25 th Anniversary Volume. The folowing publications may be suggested to the reader for tracing steps in the Geology of Japan. 1926. Geology and Mineral Resources of Japanese Empire, and annexed Geological Map, (1/2 , 000 , 000). Geol. Surv. Japan. 1931-34. Geology in Iwanami Lecture Series. (Japanese) Iwanami Book Co. 1932. Geology and Mineral Resources of Japan. 50 th Ann. Volume, Geol. Surv. Japan, (Japanese). 1941. The Sakawa Orogenic Cycle and its Bearing on the Origin of the Japanese Islands. T. KOBAYASHI. Jour. Fac. Sci. Imp. Univ. Tokyo, Sec. 2, Vol. 5, Pt. 7. 1942. Geologic Structure of Japan. Y. OTUKA. (Japanese). Dobun-Shoin. 1948. Geotectonics of the Japanese Islands, Vols. 1-2. T. KOBAYASHI. (Japanese). Meguro Book Co. 1950-54. Regional Geology of Japan. General Statement, (KOBAYASHI, 1951), Tohoku, (HANZAWA, 1954), Kwanto, (FujimoTo, 1951, 53), Chubu, (MAKIYAMA, 1950, 56), Kinki, (MATSUSHITA, 1953), Chugoku, (KOBAYASHI, 1950, 54), Shikoku, (K0BAYA- SHI, 1950, 54), Hokkaido and Kyushyu, (in preparation). (Japanese). Asakura Book Co. 4 Modern Progress of Geology in Japan 211 Table 2 . The Classification of the Cainozoic Group in Japan. 1956, 60. Geology and Mineral Resources of Japan with Geological Map of Japan, (1/ 2 , 000 , 000), Geol. Surv. Japan. Geological sheet maps of Japan (exclusive of Hokkaido)" in scale of 1/200,000 and their explanatory texts have been completed in 1919. Now those in 1/75,000 and 1/50,000 cover 1) Geological Map of Hokkaido (1/200,000) and its Explanatory Text (Japanese), 1953-58. Geolo- gical Survey of Hokkaido. Geology and Mineral Resources of Hokkaido. J. SUZUKI. " Dai-Nippon " published by Bummei Kyokwai . Bibliography of Geology of Hokkaido, 1936. Hokkaido Chishitsu-chosa-kai. 5 212 Teiichi KOBAYASHI one-quarter and 10% respectively, putting aside numerous unpublished sheet maps of which survey is already done. Besides, there are many geological maps of oil-fields, coal-fields, mining districts and so forth. The remaining part where one must rely on the old 11 200,000 scale map may be no more than 5% of the territory. Detailed informations of certain geological systems are available in the following works : 1927. Cretaceous Stratigraphy of the Japanese Islands. H. YABE. Sci. Rep. Tohoku Imp. Univ. Sendal, 2nd Ser. Vol. 11, No. 1. 1951. Triassic Stratigraphy of Japan. Compiled by 112 Committee, Japan Soc. Prom. Sci. Rep. Sp. No. A.a.l. Geol. Surv. Japan, (Japanese) 1954. The Cretaceous System in the Japanese Islands. Compiled by Cretaceous Research Comm. (Chairman, T. MATSUMOTO). Japan. Soc. Prom. Sci. 1960. Carboniferous System of Japan. Compiled by Carboniferous Research Subcomm. (Chairman, H. YABE). Rep. Sp. No. (D), A.a.l. V, Geol. Surv. Japan. 1961. The Middle Palaeozoic Group of Japan and its Bearing on her Geological History. T. HAMADA. Jour. Fac. Sci. Univ. Tokyo, Sec. 2, Vol. 13, Pt. 1. Forty years ago the oldest fossiliferous rock in Japan was Carboniferous, but Devonian and Silurian fossils were successively discovered by NODA (1934) and ONUKI (1937) in the Kitakami mountains. The existing knowledge of the two systems was recently summarized by HAMADA (1961). For the Carboniferous stratigraphy, see the committee report (1960). Corals and brachiopods were studied by YABE, HAYASAKA, MINATO and others, fusulinids by OZAWA, HANZAWA, FUJIMOTO, TORIYAMA and many others, and calcareous algae by R. ENDO, and KONISHI. The Akiyoshi, Akasaka, and other limestones and the Permo-Carboniferous group of the Southern Kitakami, the Kuma area of Kyusyu and other regions are now precisely zonated by means of fusulinids and other fossils. Of the Triassic system the Carnic stage was previously unknown and no Skytic fossil was described, but now the system of Japan devoid of the Rhaetic, is classified into 9 stages by ICHIKAWA. It is of great importance that the so-called Rhaeto-Liassic flora was proven to have appeared already in the Carnic in Japan. See Special Report of the system (1951) for details.1' Jurassic stromatoporoids were described by YABE and SUGIYAMA, corals by EGUCHI, ammonites by SATO and a few others, pelecypods by HAYAMI and some others. The stratigraphy of the system was greatly improved in recent years by KIMURA, TAMURA, MAEDA and others. The once schematized Cretaceous stratigraphy (1927) was greatly revised with a large amount of new data and the result is compiled in the committee report (1954). The system is now classified into 6 series with 2 or 3 stages in each. (See Table 1.) The advancement of the Tertiary stratigraphy was greatly accelerated by the investiga- tions of coal and petrolium prospecting (CEAC and PEAC). The system can be classfied into 14 stages. (See Table 2.) The Quaternary research became very active among geologists, palaeontologists, geographers, biologists, anthropologists, archaeologists and others 1) Recently KAMBE has ascertained that the Permo-Triassic boundary is indicated by weak discor - dance in the Maizuru zone and the Southern Kitakami and it is apparently concordant in Kyushu. The Triassic stratigraphy of the Maizuru zone was improved by NAKAZAWA and the Upper Triassic orogenic sedimentation analysed in detail by TOKUYAMA . 2) Regional Palaeoclimatology is briefly summarized in the article : The Climatic History of the Far East. T. KOBAYASHI and T. SHIKAMA. Descriptive Palaeoclimatology, 1961, Interscience Publishers, N. Y. -London . 6 Modern Progress of Geology in Japan 213 since the Japan Association for the Quaternary Research had been established in 1956.2) The Triassic, Cretaceous and Tertiary crustal movements were successively determined at some places by OZAWA, KOBAYASHI, IMAI and others in 1923-30. Ten years later KOBAYASHIschematized the tectonic development from the Chichibu geosyncline with three cycles of orogeny, causing the migration of geosyncline from the continental to the Pacific side. They are the Permo-Triassic Akiyoshi cycle, Jura-Cretaceous Sakawa cycle and the Cainozoic Oyashima crustal movements') (1941). These orogenies are each accompanied by metamorphism and plutonism. Therefore the three sets may be distinguished with prefixes, palaeo-, meso- and neo-. In addition, archaeplutonic and archaemetamorphic rocks are contained in Permian and older conglomerates, but their origin is still in chaos.
Load more

Recommended publications
  • Structural Heterogeneity in and Around the Fold-And-Thrust Belt of The
    Iwasaki et al. Earth, Planets and Space (2019) 71:103 https://doi.org/10.1186/s40623-019-1081-z FRONTIER LETTER Open Access Structural heterogeneity in and around the fold-and-thrust belt of the Hidaka Collision zone, Hokkaido, Japan and its relationship to the aftershock activity of the 2018 Hokkaido Eastern Iburi Earthquake Takaya Iwasaki1* , Noriko Tsumura2, Tanio Ito3, Kazunori Arita4, Matsubara Makoto5, Hiroshi Sato1, Eiji Kurashimo1, Naoshi Hirata1, Susumu Abe6, Katsuya Noda7, Akira Fujiwara8, Shinsuke Kikuchi9 and Kazuko Suzuki10 Abstract The Hokkaido Eastern Iburi Earthquake (M 6.7) occurred on Sep. 6, 2018 in the southern part of Central Hokkaido, Japan. Since Paleogene, this region has experienced= the dextral oblique transpression between the Eurasia and North American (Okhotsk) Plates and the subsequent collision between the Northeast Japan Arc and the Kuril Arc due to the oblique subduction of the Pacifc Plate. This earthquake occurred beneath the foreland fold-and-thrust belt of the Hidaka Collision zone developed by the collision process, and is characterized by its deep focal depth (~ 37 km) and complicated rupture process. The reanalyses of controlled source seismic data collected in the 1998–2000 Hokkaido Transect Project revealed the detailed structure beneath the fold-and-thrust belt, and its relationship with the aftershock activity of this earthquake. Our refection processing using the CRS/MDRS stacking method imaged for the frst time the lower crust and uppermost mantle structures of the Northeast Japan Arc underthrust beneath a thick (~ 5–10 km) sedimentary package of the fold-and-thrust belt. Based on the analysis of the refraction/wide- angle refection data, the total thickness of this Northeast Japan Arc crust is only 16–22 km.
    [Show full text]
  • Repeated Occurrence of Surface-Sediment Remobilization
    Ikehara et al. Earth, Planets and Space (2020) 72:114 https://doi.org/10.1186/s40623-020-01241-y FULL PAPER Open Access Repeated occurrence of surface-sediment remobilization along the landward slope of the Japan Trench by great earthquakes Ken Ikehara1* , Kazuko Usami1,2 and Toshiya Kanamatsu3 Abstract Deep-sea turbidites have been utilized to understand the history of past large earthquakes. Surface-sediment remo- bilization is considered to be a mechanism for the initiation of earthquake-induced turbidity currents, based on the studies on the event deposits formed by recent great earthquakes, such as the 2011 Tohoku-oki earthquake, although submarine slope failure has been considered to be a major contributor. However, it is still unclear that the surface-sed- iment remobilization has actually occurred in past great earthquakes. We examined a sediment core recovered from the mid-slope terrace (MST) along the Japan Trench to fnd evidence of past earthquake-induced surface-sediment remobilization. Coupled radiocarbon dates for turbidite and hemipelagic muds in the core show small age diferences (less than a few 100 years) and suggest that initiation of turbidity currents caused by the earthquake-induced surface- sediment remobilization has occurred repeatedly during the last 2300 years. On the other hand, two turbidites among the examined 11 turbidites show relatively large age diferences (~ 5000 years) that indicate the occurrence of large sea-foor disturbances such as submarine slope failures. The sedimentological (i.e., of diatomaceous nature and high sedimentation rates) and tectonic (i.e., continuous subsidence and isolated small basins) settings of the MST sedimentary basins provide favorable conditions for the repeated initiation of turbidity currents and for deposition and preservation of fne-grained turbidites.
    [Show full text]
  • FURTHER READING for the Article 'Orogenic Belts' by A. M. C. Şengör
    FURTHER READING for the article ‘Orogenic Belts’ by A. M. C. Şengör in the second edition of the Encyclopaedia of Solid Earth Geophysics published by Springer Cham., Berlin and Heidelberg. Aaron, J. M., editor, 1991, An Issue dedicated to Aspects of the Geology of Japan, Site of the 29th International Geological Congress: Episodes, v. 14, no. 3, pp. 187- 302. Akbayram, K., , Şengör, A. M. C. and Özcan, E, 2017, The evolution of the Intra- Pontide suture: Implications of the discovery of late Cretaceous–early Tertiary mélanges, in Sorkhabi, R., editor, Tectonic Evolution, Collision, and Seismicity of Southwest Asia— In Honor of Manuel Berberian’s Forty-Five Years of Research Contributions: Geological Society of America Special Paper 525, pp. 573-612. Altunkaynak, Ş., 2007, Collision-driven slab breakoff magmatism in northWestern Anatolia, Turkey: The Journal of Geology, v. 115, pp. 63-82. Anonymous, 1984, Origin and History of Marginal and Inland Seas: Proceedings of the 27th International Geological Congress, Moscow, 4-14 August 1984,v. 23, VNU Science Press, Utrecht, vii+223 pp. Arai, R., IWasaki, T., Sato, H., Abe, S. and Hirata, N., 2009, Collision and subduction structure of the Izu–Bonin arc, central Japan, revealed by refraction/wide-angle reflection analysis: Tectonophysics, v. 475, pp. 438-453. Aramaki, S. and Kushiro, I., editors, 1983, Arc Volcanism: Elsevier, Amsterdam, VII+652 pp. Arkle, J. C., Armstrong, P. A., Haeussler, P. J., Prior, M. G., Harman, S., Sendziak, K. L. and Brush, J. A., 2013, Focused exhumation in the syntaxis of the Western Chugach Mountains and Prince William Sound, Alaska: Geological Society of America Bulletin, v.
    [Show full text]
  • 27. Sedimentary Facies Evolution of the Nankai Forearc and Its Implications for the Growth of the Shimanto Accretionary Prism1
    Hill, I.A., Taira, A., Firth, J.V., et al., 1993 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 131 27. SEDIMENTARY FACIES EVOLUTION OF THE NANKAI FOREARC AND ITS IMPLICATIONS FOR THE GROWTH OF THE SHIMANTO ACCRETIONARY PRISM1 Asahiko Taira2 and Juichiro Ashi2 ABSTRACT A combination of Deep Sea Drilling Project-Ocean Drilling Program drilling results and site survey data in the Shikoku Basin, Nankai Trough, and Nankai landward slope region provides a unique opportunity to investigate the sedimentary facies evolution in the clastic-dominated accretionary forearc. Here, we consider the facies evolution model based on the drilling results, IZANAGI sidescan images, and seismic reflection profiles. The sedimentary facies model of the Nankai forearc proposed in this paper is composed of two parts: the ocean floor-trench- lower slope sedimentary facies evolution and the upper slope to forearc basin sedimentary facies evolution. The former begins with basal pelagic and hemipelagic mudstones overlain by a coarsening upward sequence of trench turbidites which are, in turn, covered by slope apron slumps and lower slope hemipelagic mudstone. This assemblage is progressively faulted and folded into a consolidated accretionary prism that is then fractured and faulted in the upper slope region. Massive failure of the seafloor in the upper slope region produces olistostrome deposits that contain lithified blocks derived from older accretionary prism dispersed in a mud matrix. The contact between the older accretionary prism and the upper slope olistostrome is a submarine unconformity that is the first stratigraphic evidence for the exhumation of an older prism to the seafloor. The olistostrome beds are then overlain by forearc basin-plain mudstone and turbidites which are progressively covered by coarsening-upward delta-shelf sequences.
    [Show full text]
  • The Khopik Porphyry Copper Prospect, Lut Block, Eastern Iran: Geology, Alteration and Mineralization, fluid Inclusion, and Oxygen Isotope Studies
    OREGEO-01217; No of Pages 23 Ore Geology Reviews xxx (2014) xxx–xxx Contents lists available at ScienceDirect Ore Geology Reviews journal homepage: www.elsevier.com/locate/oregeorev The Khopik porphyry copper prospect, Lut Block, Eastern Iran: Geology, alteration and mineralization, fluid inclusion, and oxygen isotope studies A. Malekzadeh Shafaroudi a,⁎,M.H.Karimpoura, C.R. Stern b a Research Center for Ore Deposits of Eastern Iran, Ferdowsi University of Mashhad, Iran b Department of Geological Sciences, University of Colorado, CB-399, Boulder, CO 80309-399, USA article info abstract Article history: The Khopik porphyry copper (Au, Mo) prospect in Eastern Iran is associated with a succession of Middle to Late Received 14 October 2012 Eocene I-type, high-K, calc-alkaline to shoshonite, monzonitic to dioritic subvolcanic porphyry stocks emplaced Received in revised form 16 April 2014 within cogenetic volcanic rocks. Laser-ablation U-Pb zircon ages indicate that the monzonite stocks crystallized Accepted 21 April 2014 over a short time span during the Middle Eocene (39.0 ± 0.8 Ma to 38.2 ± 0.8 Ma) as result of subduction of Available online xxxx the Afghan block beneath the Lut block. Keywords: Porphyry copper mineralization is hosted by the monzonitic intrusions and is associated with a hydrothermal alter- Porphyry copper ation that includes potassic, sericitic-potassic, quartz-sericite-carbonate-pyrite (QSCP), quartz-carbonate-pyrite Khopik (QCP), and propylitic zones. Mineralization occurs as disseminated to stockwork styles, and as minor hydrothermal Lut Block breccias. Some mineralization occurs in fault zones as quartz-sulfide veins telescoped onto the porphyry system.
    [Show full text]
  • (EEL2019) Field Excursion Guide Convergent Plate Boundary
    EPS-ELSI Winter School “Evolution of Earth & Life” (EEL2019) Field Excursion Guide Convergent Plate Boundary & Geology of Island Arc in Tanzawa area, Japan Excursion Leader: Yuichiro Ueno Guidebook Editor: Tomohiko Sato, Shigenori Maruyama Dec. 2nd – Dec. 3rd, 2019 1 1. Introduction Japan is a unique place to study plate tectonics because the island located at the convergent plate boundary. In order to understand the collisional orogeny and crustal evolution, we plan to visit Tanzawa Mountain in the Izu-Hakone region, where we can observe how the Philippine Sea Plate subducted below the island arc in the field. Through the geology of the convergent plate boundary, we are able to consider how the continental crust evolve through the history of the Earth. 2. Geology of Japan Four plates meet around Japan island arc along the subduction zone The subduction of the Pacific Plate under the Philippine Sea Plate creates a Izu-Bonin-Mariana Arc, where many volcanic islands are distributed. The Philippine Sea Plate is now moving 3 ~ 5 cm/year to the north and is subducted under Eurasian and North American Plates, which create a main Japan island (Honshu Arc). The famous Mt. Fuji is located near the triple junction of the three plates, where the oceanic islands collided with the Honshu Arc at Izu-Hakone region (Red box in Fig.2). Also, the back arc basins (Japan Sea and Okinawa Trough) are spreading since about 20 million years ago. Fig. 1. Plate boundaries around Japan. Red box is Izu-Hakone area, very rare region on the Earth having triple junction where the boundaries of three tectonic plates meet.
    [Show full text]
  • The Geology of Japan Moreno, S
    Spine width 24.5mm Edited by Edited Edited by T. T. Moreno, S. Wallis, T. Kojima & W. Gibbons The Geology of Japan S. Moreno, Wallis, T. Wallis, Edited by T. Moreno, S. Wallis, T. Kojima & W. Gibbons Kojima It has been 25 years since publication of the most recent English language summary of the geology of Japan. This book offers an up-to- W. & date comprehensive guide for those interested both in the geology of Gibbons The Geology of Japan the Japanese islands and geological processes of island arcs in general. It contains contributions from over 70 different eminent researchers in their fields and is divided into 12 main chapters: Geological Evolution of Japan: an Overview ; • The • Regional Tectonostratigraphy (consisting of seven separate sections giving full coverage both to the different geographic regions and different geological ages); Geology of Japan • Ophiolites and Ultramafic Units ; • Granitic Rocks; • Miocene–Holocene Volcanism; • Neogene–Quaternary Sedimentary Successions; • Deep Seismic Structure; • Crustal Earthquakes; • Coastal Geology and Oceanography; • Mineral and Hydrocarbon Resources; • Engineering Geology; • Field Geotraverse, Geoparks and Geomuseums (with information on travelling by public transport to see some of the great geological sites of Japan). Each chapter includes the unique contribution of an extensive aid to the written forms of geology-related names in Japanese. Front cover: Red Fuji, also known as south wind, clear sky, from the 36 views of Mt Fuji by Hokusai (1760–1849). Image courtesy of S. Wallis.
    [Show full text]
  • New View of the Stratigraphy of the Tetori Group in Central Japan
    Memoir of the Fukui Prefectural Dinosaur Museum 14: 25–61 (2015) REVIEW © by the Fukui Prefectural Dinosaur Museum NEW VIEW OF THE STRATIGRAPHY OF THE TETORI GROUP IN CENTRAL JAPAN Shin-ichi SANO Fukui Prefectural Dinosaur Museum Terao, Muroko, Katsuyama, Fukui 911-8601, Japan ABSTRACT The stratigraphy of the Tetori Group (sensu lato) and other Early Cretaceous strata in the Hakusan Region in the Hida Belt, northern Central Japan, is reviewed based on recent advances in ammonoid biostratigraphy, U-Pb age determination of zircons using inductively coupled plasma-mass spectrometry with laser ablation sampling (LA-ICPMS), recognition of marine influence, and climatic change inferred from the occurrences of thermophilic plants and pedogenetic calcareous nodules. Four depositional stages (DS) are recognized: DS1 (Late Bathonian–Middle Oxfordian)̶mainly marine strata characterized by the occurrences of ammonoids; DS2 (Berriasian–Late Hauterivian)̶mainly brackish strata characterized by the occurrences of Myrene (Mesocorbicula) tetoriensis and Tetoria yokoyamai; DS3 (Barremian– Aptian)̶fluvial strata characterized by the occurrence of abundant quartzose gravels and freshwater molluscs, such as Trigonioides, Plicatounio and Nippononaia; DS4 (Albian–Cenomanian)̶volcanic/plutonic rocks which unconformably covered or intruded into the Tetori Group. I here propose new interpretation that 1) the Tetori Group (s.l.) in the Hakusan Region in the Hida Belt is divided into Middle–Late Jurassic Kuzuryu Group (corresponding to DS1) and unconformably overlying Early Cretaceous Tetori Group (sensu stricto) (corresponding to DS2–3); and 2) the Tetori Group (s.l.) in other areas is separated from the Tetori Group (s.s.), and divided into the Late Jurassic strata of the Kuzuryu Group (corresponding to the upper part of the same group in the Hakusan Region) and the Early Cretaceous Jinzu Group in the Jinzu Region in the Hida Belt, and the Late Jurassic–Early Cretaceous Managawa Group in the Hida Gaien Belt.
    [Show full text]
  • The Exploration Potential of Japan
    16 Received January 17, 2018 Review Accepted for Publication January 24, 2018 ©2018 Soc. Mater. Eng. Resour. Japan The Exploration Potential of Japan Antonio ARRIBAS ＊International Center for Research and Education on Mineral and Energy Resources (ICREMER) Graduate School of International Resource Sciences, Akita University, Akita 010-8502, Japan E-mail : [email protected] This report presents a review and analysis of the relevant geological, metallogenic, metal production and mineral exploration history of northern Tōhoku to discuss the exploration potential of the region and Japan. The interpretation is based mainly on empirical and practical arguments, in contrast to the also important petrogenetic and tectonic criteria. The case is made that for the discussion of the mineralization potential of Japan, northern To－hoku serves as a valid proxy. One conclusion is that ignifi cant exploration on land in Japan for base- and precious-metal deposits, in particular for porphyry copper type systems, stopped too early, before it could have benefi tted from key metallogenic developments of the past 25+ years. The full mineralization potential of Japan is excellent and far from being fully realized. Key Words : Japan, To－hoku, exploration, hydrothermal ore deposits, gold, copper, silver, zinc sedimentary rocks accompanied by subsidiary limestones, cherts, 1 INTRODUCTION and basalts. Together with the older rocks of the southern Kitakami Japan is a land rich in mineral deposits, with a long mining history [1]. Access to the mineral riches of Zipangu, as Japan was known in Europe from Marco Polo’ s accounts, was one of the drivers behind Columbus’ expedition from Spain to the West and discovery of a new, mineral-rich landmass (the Americas).
    [Show full text]
  • The Plate-Tectonics Interpretations of the Japanese Paired Metamorphic
    地 学 雑 誌 84, 4 (1974) The Plate-Tectonics Interpretations of the Japanese Paired Metamorphic Belts•\An Armchair Appraisal Chao-Siang WANG* ABSTRACT The Japanese Akiyoshi and Sakawa paired metamorphic belts recognized and documented by MIYASHIRO appear most likely apparent pairs consisting of high pressure belts survived from Palaeozoic origin and low pressure belts created due to Mesozoic convergence. In general, the age of regional metamorphism is younger than that of the original sedimentaries and igneous rocks. And in plate tectonics considerations, both members of the metamorphic pair are coeval but their age of formation can't be younger than that of their non-metamorphic equivalent sedimenta- ries which were formed as an arc-trench-gap or a convergence-relaxation/cessation deposit derived from the same continent. Among the six Japanese stratigraphic- structural zones (Table 1) originated from the Chichibu geosyncline , the non-meta- morphic Yamaguchi in the Sangun-Hida pair and Chichibu in the Sambagawa-Ryoke combination are considered as such ;the Sangun and Sambagawa high pressure belts are therefore regarded as being formedin the trench-subduction zones not younger than Permo-Carboniferous. Such an original age of origin for the paired metamor- phic belts is also supported from the stratigraphic evidence as well as fromthe radiometric dates. The apparent Mesozoic ages are believed to be resulted from overprinting by thermal events due to Akiyoshi-Sakawa plate convergence with concurrent uplifting and subsidence. Mainly through the works of KOBAYASHI (1941) and others (KIMURA et al., 1971 TAKAI et al., 1963 ; MATSUMOTO, 1967), the Japanese Islands are known to have developed out of the Palaeozoic-Early Mesozoic Chichibu geosyncline, the Mesozoic-Early Tertiary Shimanto (and Nakamura) geosyncline, and the Neogene geosyncline successively accreted along the Pacific margin.
    [Show full text]
  • A Stable Location Within Active Japan
    Tetsumaru Itaya Earth & Environment︱ The Kibi Plateau is a peneplain, an area of land that is mostly level and unaffected by crustal into the Pacific Ocean. As they flow movement. At 777 m, Mount Tenjin is the highest point within the Kibi Plateau (arrow). across older geological formations, they deposit sediments on top which became layers of fluvial (river) deposits. Dr Itaya and his team have found that on the Kibi Plateau, despite being in such a geologically active area where movement of the Earth’s surface occurs frequently through faulting and folding, the fluvial deposits show no record of AKibi stable location Plateauwithin active Japan any vertical or horizontal displacement. The coastal, shallow marine sediments also found in this area show no significant The Japan Islands experience he Earth is a geologically dynamic infrastructure in Japan, including the inclination (tilting), which would have some of the most extreme planet. The rigid tectonic plates Fukushima Daiichi Nuclear Power Plant. been evidence of uplift or tilting caused earthquakes and volcanoes Tcovering its surface may be moving by movement of the crust. This suggests in the world. Located on the far slower than we can feel, but we Earthquakes are one of the most violent boundaries (where one rigid crustal The Kibi Plateau is a peneplain, an area that the Kibi Plateau has been a stable subduction junction between certainly feel the effects. The occurrence natural hazards on Earth, and despite plate is slowly sliding beneath another). of land that is mostly level and is not unit experiencing a very minimal rate of four different continental of earthquakes caused by tectonic plates years of work, geologists still cannot The Japanese Islands are situated affected by crustal movement.
    [Show full text]
  • Uraninite and Thorite Ages of Around 400 Granitoids in the Japanese Islands
    国立科博専報，(51), pp. 1–24 , 2016 年 3 月 28 日 Mem. Natl. Mus. Nat. Sci., Tokyo, (51), pp. 1–24, March 28, 2016 Uraninite and Thorite Ages of Around 400 Granitoids in the Japanese Islands Kazumi Yokoyama1*, Masako Shigeoka1, Yukiko Otomo2, Kouta Tokuno3 and Yukiyasu Tsutsumi1 1 Department of Geology and Paleontology, National Museum of Nature and Science, 4–1–1 Amakubo, Tsukuba, Ibaraki 305–0005, Japan 2 Faculty of Education, Art and Science, Yamagata University, 1–4–12 Kojirakawa-machi, Yamagata-shi, Yamagata 990–8560, Japan 3 Earth and Planetary Science, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819–0395, Japan * E-mail: [email protected] Abstract. Systematic dating of around 400 granitoids in the Japanese Islands have been made on the basis of total UO2, ThO2 and PbO contents of uraninite and anhydrous thorite using an electron microprobe analyzer (EPMA) at the National Museum of Nature and Science, Tokyo. The ages range from ca. 5 Ma to 300 Ma. From the granitoid ages, the Japanese Islands were divided into many terranes. In northern Japan, granitoids with ages of approximately 110–120 Ma occur in the Kitakami Mountains, southwest Hokkaido and eastern Abukuma Mountains, and granitoids with ages of approximately 100–110 Ma occur at the western Abukuma Mountains and its northern extension. The granitoids that are around 90–100 Ma old occur sporadically in the Japanese Islands: mainly in the Asahi Mountains, the Nikko area, northern Shikoku and northern Kyushu. In central and northern Japan, the younger Cretaceous granitoids, partly Paleogene, with an age of around 65 Ma occur along the western part of the Asahi Mountains and Tsukuba–Nikkou area.
    [Show full text]