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Volume 56 (2002)
- Issue 6 Pages 321-
- Issue 5 Pages 253-
- Issue 4 Pages 215-
- Issue 3 Pages 141-
- Issue 2 Pages 63-
- Issue 1 Pages 1-
Volume 56, Issue 2
Displaying 1-5 of 5 articles from this issue
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Masanori HIRASAWAArticle type: Article
2002 Volume 56 Issue 2 Pages 63-64
Published: March 25, 2002
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSDownload PDF (883K) -
Matsumoto Basin Collaborative Research GroupArticle type: Article
2002 Volume 56 Issue 2 Pages 65-85
Published: March 25, 2002
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSThe Ontake volcano is situated at the southern end of the Norikura volcanic chain, central Japan. The Ontake volcano consists of the Older Ontake Volcano (Middle Pleistocene) and the Younger Ontake Volcano (Late Pleistocene). The Tarusawa Formation (Middle Pleistocene) corresponds to the volcanic sediments of the Older Ontake Volcano, and is classified into the lower and upper members. The lower member is mainly composed of volcaniclastic material and intercalates numerous air fall tephra beds, thin lavas and pyroclastic flow deposits. The upper member is mainly composed of lavas and intercalates a few air fall tephra beds. Several marker tephra beds are intercalated in the volcanic sediments; these are, Satomiya Pumice, Kanbara Pumice I, II, III in the lower member of the Tarusawa Formation, and Hottaruzawa Pumice in the upper member. Each of these marker tephra bed is distributed around the Ontake volcano. The marker tephra beds are characterized by high content of hornblende except for Hottaruzawa Pumice which is characterized by biotite. The volcanic activity of the Older Ontake Volcano was revealed by means of volcanostratigraphy, tephrostratigraphy and K-Ar age dating of lavas. The activity can be divided into a tephra-stage (0.78-0.64 Ma) and a lava-stage (0.64-0.39 Ma). Volcanic products of the tephra-stage almost correspond to the lower member, and those of the lava-stage to the upper member of the Tarusawa Formation. The volcanic activity of the tephrastage was mostly explosive, forming air fall tephras and pyroclastic flows. Those tephra beds may have been entrained in a number of debris flows, which formed the major part of the eastern body of the Older Ontake Volcano. The volcanic activity of the lava-stage was less explosive, and produced a large number of lava flows. These lava flows almost entirely covered the foot areas and formed edifice of the Older Ontake Volcano.View full abstractDownload PDF (3576K) -
Kazue TAZAKI, Kaori HASEGAWA, Kazuya MATSUMOTOArticle type: Article
2002 Volume 56 Issue 2 Pages 87-104
Published: March 25, 2002
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSContamination of water and soils is one of grave problems at mining area. Kamioka Mine, one of the largest Zn-Pb mine in Gifu prefecture in Japan, has been the source of heavy metal pollution in Jinzu River. Cd, Pb, Zn, and Fe have been released from an abandoned dump into the Takahara-Jinzu River system, and serious health problem occurred in the down stream areas. Heavy metals, Cd, in particular, is regarded to be the pathogenic substance causing Itai-Itai Disease. The Cd pollution problems have not yet been solved. Some tailing ponds with neutralizing coagulation treatment (slaked lime) are present in the Kamioka Mine. Heavy metal-contaminated wasted water from tailing and dumping areas were discharged into the Takahara River (the upper stream of the Jinzu River). In this study, five dam sediments along the Takahara-Jinzu River were collected, in order to clarify characteristics of sediments with heavy metals. Each sample was analyzed by using an X-ray powder diffractometer (XRD) and an energy dispersive X-ray fluorescence analyzer (ED-XRF) in order to clarify the mineralogical and chemical compositions of the dam sediments. As a result, the sediment from Asaida dam on the upper course of the Kamioka Mine has little Cd, clay minerals and organic matter, whereas Shininotani dam, Jinzu 1st dam, Jinzu 2nd dam, Jinzu 3rd dam in the down stream of the Kamioka Mine have much sludge, smectite and heavy metals, such as Zn and Cd. Smectite and organic matter have been concentrated with heavy metals in the down stream dam sediments of Jinzu River. In this study, arrange of experimental observation has carried out in order to estimate the ability of heavy metals for the purification of water. The results suggest that bioremediation methods using bacteria is effective as a fixing heavy metals. Filamentous bacteria in biofloc selectively accumulated Pb, Zn, and Cd on the surface of cell wall in laboratory experimental system after one week aging. The bacteria have an ability as a bioremediation, play a key role in the fixation of heavy metals in the down stream dam sediments at mining area.View full abstractDownload PDF (2716K) -
Takashi FUKUOKA, Seiji MATSUIArticle type: Article
2002 Volume 56 Issue 2 Pages 105-122
Published: March 25, 2002
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSMt. Sanbe, located in the the middle of the Shimane Prefecture, southwest Japan, erupted in the late Quaternary. Researchers remain divided on the stratigraphy and the classification of the stages of activity. We have re-examined the stratigraphy and activity of deposits younger than the AT tephra. Petrography of the volcanic products and bulk rock chemistry were also examined using XRF and INAA. Based on these data, new stratigraphic units are distinguished which we have redefine as the Hikageyama Lava, Hatasedani Pyroclastic Flow Deposit, Oda Surge Deposit, Oda Pyroclastic Flow Deposit, Ukinuno Pumice Fall Deposit, Midorigaoka Pyroclastic Flow Deposit, Ukinuno Ash Fall Deposit, Kiriwari Ash Fall Deposit, Shigaku Ash Fall Deposit, Shigaku Pyroclastic Flow Deposit, Tsunoi Ash Fall Deposit, Shitsumi Ash Fall Deposit, Tateishi Debris Avalanche Deposit, Sanbe Dome Lava, Taiheizan Pyroclastic Deposit, Ibidani Debris Avalanche Deposit and Summit Ash Deposit. Six soil deposits identified between the tephras. These are the Ikeda Paleosol, Fourth Black Soil, Third Black Soil, Second Black Soil, First Black Soil and the Summit Black Soil. Glass shards from the widespread AT and K-Ah tephras were found in the Ikeda Paleosol and the Third Black Soil, respectively. These soils represent hiatuses in volcanic activity. The active stages of Sanbe Volcano are also redefined from Stages IV to VIII based on the soil deposits.View full abstractDownload PDF (3015K) -
Yukihiko KAMOI, Satoshi YASUI, Iwao KOBAYASHIArticle type: Article
2002 Volume 56 Issue 2 Pages 123-138
Published: March 25, 2002
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSTen drilling cores that reached the basement of Alluvium in the central Echigo Plain were examined lithologically and chronologically. The Alluvium of which time-planes were drawn up according to many 14C dates was divided into nine members. As a result, some new knowledges of sedimentary process were obtained as follows. 1) The formational process of the Echigo plain can be divided into four sedimentary stages as follows. Stage I: The beginnings of transgression; late glacial stage (ca. 15,000 to 10,000 yrs BP). Stage II: The expansion of drowned valley; early Holocene (ca. 10,000 to 8,000 yrs BP). Stage III: The appearance of barrier system; transgressive and high standing stage of the Jomon Transgression (ca. 8,000 to 5,000 yrs BP). Stage IV: The development of strand plain and disappearance of lagoon; after high standing stage of the Jomon Transgression (ca. 5,000 yrs BP to present). 2) The deposition of Alluvium in the Echigo plain began at the late glacial stage. 3) Any unconformity is not found in the Alluvium of the Echigo Plain. The uppermost Pleistocene to Holocene was deposited continuously. 4) Assuming that 10,000 yrs BP is Holocene basement horizon, the depth of position is -100m in the coastal area of the Plain and -70m in the inland area respectively. 5) A subsurface sand bank with NE-SW elongation is located on the central part of the Echigo Plain. It probably continues to the New Sand Dune I. The appearance of a large lagoon in the Shirone area was probably caused by this sand bank.View full abstractDownload PDF (2687K)
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