کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4437502 1620265 2005 20 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Hydrochemical baseline condition of groundwater at the Mizunami underground research laboratory (MIU)
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Hydrochemical baseline condition of groundwater at the Mizunami underground research laboratory (MIU)
چکیده انگلیسی
Hydrochemical conditions up to depths of 1000 m below ground level around the Mizunami Underground Research Laboratory were investigated to construct a “baseline condition model” describing the undisturbed hydrochemical environment prior to excavation of the underground facilities at Mizunami, Gifu, Japan. Groundwater chemistry in this area was classified into a Na-Ca-HCO3 type of groundwater in the upper part of sedimentary rock sequence and a Na-(Ca)-Cl type of groundwater in the deeper part of the sedimentary rock sequence and basement granite. The residence time of the groundwaters was estimated from their 14C contents to be approximately 9.3 ka in the middle part of the sedimentary rock and older than 50 ka in the deep part of the granite. The evolution processes of these groundwaters were inferred to be water-rock interactions such as weathering of plagioclase, dissolution of marine sulphate/sulphide minerals and carbonate minerals in the Na-Ca-HCO3 type of groundwater, and mixing between “low-salinity water” in the shallow part and “higher-salinity water” in the deeper part of the granite in the Na-(Ca)-Cl type of groundwater. The source of salinity in the deeper part of the granite was possibly a palaeo-hydrothermal water or a fossil seawater that recharged in the Miocene, subsequently being modified by long-term water-rock interaction. The Cl-depth trend in granitic groundwater changes at a depth of −400 m below sea level. The hydrogeological properties controlling the groundwater flow and/or mixing processes such as advection and diffusion were inferred to be different at this depth in the granite. This hydrochemical conceptual model is indispensable not only when constructing the numerical model for evaluating the hydrochemical disturbance during construction and operation of the MIU facility, but also when confirming a hydrogeological model.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Geochemistry - Volume 20, Issue 12, December 2005, Pages 2283-2302
نویسندگان
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