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Volume 33 (1999)
- Issue 4 Pages 207-
- Issue 3 Pages 141-
- Issue 2 Pages 67-
- Issue 1 Pages 1-
Volume 33, Issue 1
Displaying 1-5 of 5 articles from this issue
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Review in series “New Approaches to Geochemistry”
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Kazuhiro SUZUKI, Mamoru ADACHI, Takenori KATO, Setsuo YOGO1999 Volume 33 Issue 1 Pages 1-22
Published: March 10, 1999
Released on J-STAGE: December 27, 2016
JOURNAL FREE ACCESSThis paper outlines the CHIME (chemical Th-U-total Pb isochron method: Suzuki and Adachi, 1991a, b; Adachi and Suzuki, 1992) dating method and reviews its application to the event analysis of orogenic belts. The reviewed examples of the CHIME geochronology include (1) the electron microprobe observations of Pb diffusion in metamorphosed detrital monazites from high-grade Ryoke paragneisses (Suzuki et al., 1994), (2) the recycled Precambrian clastic materials from the Mino terrane (Adachi and Suzuki, 1993, 1994), (3) the late Permian-early Triassic metamorphism and plutonism in the Hida terrane (Suzuki and Adachi, 1991b, 1994), (4) the relationship between the Hikami Granite and Siluro-Devonian clastic rocks in the South Kitakani terrane (Suzuki et al., 1992 ; Adachi et al., 1994), and (5) the denudation history of the high T/P Ryoke metamorphic belt (Suzuki and Adachi, 1998). The CHIME dating method is based on precise electron microprobe analyses of Th, U and Pb as low as 0.01wt.% in an area of 5um across within a single grain of compositionally ununiformed Th-and U-bearing accessory minerals like monazite and zircon. This method has an advantage of high spatial resolution, and provides a new vista on the study of igneous, metamorphic and sedimentary rocks that underwent complex thermo-tectonic history. Monazite is most suitable to the CHIME dating, since it shows a concordant Th-U-Pb relation, contains 5-20wt.% ThO2 and 0.1-1.5wt.% UO2 that can produce 0.01-0.06wt.% PbO during 50 Myr, and remains immune to significant Pb-loss during the sillimanite grade metamorphism ; it has great chronological potential for the analysis of the detailed sequence of geologic events.View full abstractDownload PDF (2041K)
Review
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Atsushi SUZUKI, Youichi TANIMOTO, Hodaka KAWAHATA1999 Volume 33 Issue 1 Pages 23-44
Published: March 10, 1999
Released on J-STAGE: December 27, 2016
JOURNAL FREE ACCESSWe describe recent progress in palaeo-environmental studies using coral skeletal records. Coral skeletons are excellent archives for considerable and diverse environmental information from tropical oceans. A high precision micro-sampling technique has allowed us to reconstruct high-resolution proxy climate records using the annual density bands of massive corals such as Porites spp. The combination of high-precision oxygen stable isotope analysis and Sr/Ca thermometry is one of the most promising methods for the reconstruction of palaeo-seawater temperature and water budgets including rainfall, evaporation and deep water upwelling. Coral proxy records will contribute to the understanding of the nature of past climate changes, including El Niño-Southern Oscillation (ENSO) and the Asian monsoon. We also introduce coral records spanning more than 100 years, which provided a unique insight into the low-frequency features of ENSO related phenomena in the tropical Indian and Pacific Oceans.View full abstractDownload PDF (2620K)
Original Paper
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Katsuto KOBAYASHI, Osamu MATSUBAYA, Hiroshi KAWARAYA, Noriko MUTO1999 Volume 33 Issue 1 Pages 45-53
Published: March 10, 1999
Released on J-STAGE: December 27, 2016
JOURNAL FREE ACCESSGroundwater from bore holes penetrating into the sliding debris are studied with respect to isotopic and anion compositions. The groundwater from individual bore holes has characteristic isotopic and chemical features. The Cl- and SO42- contents and also the δD and δ18O show two mixing relationships, respectively, though these relationships are only partly accordant between anion and isotopic one. These relationships and the HCO3- contents can be interpreted as the result of 4 components mixing, i. e. (1) shallow groundwater similar to the surface water, (2) thermal water of NaCl-type and of meteoric water origin similar to the Zenikawa hot spring, (3) steam separated by boiling from the thermal water of NaCl-type, and (4) thermal water of SO4 type, the origin of which is not obvious, but may be the same as the Sumikawa hot spring of volcanic steam origin. Different mixing manners occuring within a close distance suggest that these two thermal waters are individually coming up through separate vertical fissures. Temperature and pH of the groundwater seem to be controlled by interaction with rocks.View full abstractDownload PDF (822K) -
Akinori ITOH, Ichiro TAKAHAHSI, Yoko NAGATA, Hideyuki SAWATARI, Koichi ...1999 Volume 33 Issue 1 Pages 55-64
Published: March 10, 1999
Released on J-STAGE: December 27, 2016
JOURNAL FREE ACCESSIn order to elucidate the phenomenon that the atmospheric methane (CH4) concentration is higher in urban area, the influences of urban atmospheric structure on the temporal and geographical distributions of atmospheric CH4 concentrations have been investigated in relation with the meteorological conditions by analyzing the continuous monitoring data in Nagoya City. When the CH4 concentrations became higher in the downtown area during the daytime, the vertical profiles of potential temperature showed the stable atmospheric conditions above the urban area and the geographical distributions of wind speed and direction exhibited the stagnant atmospheric region around the urban surface area. These results suggested the stagnancy of a smog layer in the urban atmosphere. Statistical analysis of the concentrations of greenhouse gases (CO2, CH4) and air pollutants (CO, NMVOCs) as well as meteorological data through the year of 1995 also indicated that the concentration variation of CH4 was deeply related to the smog layer formation under the stable atmospheric conditions. Thus, it is concluded that the higher concentration of CH4 in urban area was observed even in the daytime when a smog layer was formed under fine weather and weak wind conditions.View full abstractDownload PDF (901K)
Abstract of doctoral thesis
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Hidetoshi Kumata1999 Volume 33 Issue 1 Pages 65-
Published: March 10, 1999
Released on J-STAGE: December 27, 2016
JOURNAL FREE ACCESSDownload PDF (190K)
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