Hydrochemical and isotopic (d2H, d18O, 3H) characterization of fracture water in crystalline rock (Grimsel, Switzerland)

Schneeberger, Raphael; Mäder, Urs; Waber, Niklaus (2017). Hydrochemical and isotopic (d2H, d18O, 3H) characterization of fracture water in crystalline rock (Grimsel, Switzerland). Procedia earth and planetary science, 17, pp. 738-741. Elsevier 10.1016/j.proeps.2016.12.187

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Knowledge on water circulation through crystalline rock is of key interest for radioactive waste disposal, geothermal projects or
groundwater supply. This study presents first results of long-term monitoring of fracture groundwater chemical and isotope
compositions combined with structural data on fracture networks developed in the crystalline rocks at the Grimsel Test Site
(GTS), Switzerland. Groundwater circulation in the two major lithologies, the Central Aar Granite (CaGr) and the Grimsel
Granodiorite (GrGr) is mainly associated to NE-SW trending brittle deformation structures. Within the different lithologies
groundwater chemical and water isotope (delta18O, delta 2H) compositions remain constant over the 2 years monitoring period. This
suggests the absence of seasonal variations at the sampling depth of 420–520 m below surface. Differences in chemical and
isotope composition occur, however, between groundwater collected from the CaGr and GrGr and can be related to differences in
infiltration area, flow paths, residence time and water-rock interaction in the two rock units. The delta 2H and delta 18O signatures indicate
a meteoric origin from the same moisture sources under present-day climatic conditions and the absence of measurable 3H
suggests residence times > 65 yrs for groundwater from both units.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Schneeberger, Raphael; Mäder, Urs and Waber, Niklaus

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

1878-5220

Publisher:

Elsevier

Language:

English

Submitter:

Niklaus Waber

Date Deposited:

28 Apr 2017 13:35

Last Modified:

28 Apr 2017 13:35

Publisher DOI:

10.1016/j.proeps.2016.12.187

Uncontrolled Keywords:

fracture water, crystalline rocks, Grimsel Test Site

BORIS DOI:

10.7892/boris.95851

URI:

https://boris.unibe.ch/id/eprint/95851

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