Japan Geoscience Union Meeting 2016

Presentation information


Symbol A (Atmospheric and Hydrospheric Sciences) » A-HW Hydrology & Water Environment

[A-HW18] Isotope Hydrology 2016

Wed. May 25, 2016 9:00 AM - 10:30 AM 202 (2F)

Convener:*Masaya Yasuhara(Rissho Univ.), Kohei Kazahaya(Geological Survey of Japan, AIST), Kazuyoshi Asai(Geo Science Laboratory), Shinji Ohsawa(Institute for Geothermal Sciences, Graduate School of Science, Kyoto University), Futaba Kazama(Social Cystem Engineering, Division of Engineering, Interdiciplinary Graduate School of Medical and Engineering, University of Yamanashi), Masaaki Takahashi(The National Institute of Advanced Industrial Science and Technology), YUICHI SUZUKI(Faculty of Geo-Environmental Sience,Rissho University), Chair:Masaya Yasuhara(Rissho Univ.)

9:45 AM - 10:00 AM

[AHW18-03] Isotopic and chemical characteristics of well waters around Mt. Fuji

*Muga Yaguchi1, Takeshi Ohba1, Kosuke Sango1 (1.Department of Chemistry, School of Science, Tokai University)

Keywords:Mt. Fuji, well water, hot spring water, stable isotope ratio (δD·δ18O), water quality

In this study, 14 water samples were collected from wells of various depths from 4 to 1,500m and from natural springs around Mt. Fuji, and were subjected to chemical and isotopic analysis of hydrogen and oxygen (δD and δ18O).
The δD and δ18O values of the water samples ranged from -86.4 to -49.6‰ and from –11.6 to -7.6‰, respectively, and negative correlation was recognized between isotope ratio and altitude of sampling point. Relationship between δD and δ18O for sample waters was δD = 8·δ18O + 12, and is very close to the local and global meteoric water lines (δD = 8·δ18O + 15.1 from Yasuhara et al., 2007 and δD = 8·δ18O + 10 from Craig, 1961, respectively). Altitude effect of δD and δ18O in sample waters (altitude of sampling point was used in calculation) were calculated at -3.5‰ and -0.43‰ per 100m altitude, respectively. These isotopic gradients are mostly the same as published values for rain and snow (-3.0‰/100m for δD and -0.4‰/100m for δ18O; Waseda and Nakai, 1983). Based on the trilinear diagram, water samples were basically classified as Ca–HCO3 type at shallow depths (0~15m depth), mixed cation–HCO3 type at intermediate depths (less than about 200m), Ca·Na–SO4·Cl and Na·Ca–SO4·HCO3 types or similar to them at more deep depth. Water qualities of deep wells appeared to be derived from submarine sediments and volcanic rocks which compose the basement of Mt. Fuji region because the water qualities of deep wells are similar to that of thermal water in the green tuff region of Japan (Sakai and Matsubaya, 1974).