Econ. Environ. Geol. 2002; 35(1): 13-23

Published online February 28, 2002

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Estimation of Geochemical Evolution Path of Groundwaters from Crystalline Rock by Reaction Path Modeling

Kyu-Youl Sung1*, Maeng-Eon Park1, Yong Kwon Koh2 and Chun Soo Kim2

1Dept. Environ. Geosci., Pukyong National University, Busan 608-737, Korea
2Korea Atomic Energy Research Institute, Taejon 305-600, Korea

Correspondence to :

Kyu-Youl Sung

sungky@mail1.pknu.ac.kr

Received: December 3, 2001; Accepted: February 21, 2002

Abstract

The chemical compositions of groundwaters from the granite areas mainly belong to Ca-HCO3 and Na-HCO3 type, and some of these belong to Ca-(Cl+SO4) and Na-(Cl+SO4) type. Spring waters and groundwaters from anorthosite areas belong to Ca-HCO3 and Na-HCO3 type, respectively. The result of reaction path modeling shows that the chemical compositions of aqueous solution reacted with granite evolve from initial Ca-Cl type, via Ca-HCO3 type, to Na-HCO3 type. The result of rain water-anorthosite interaction is similar to evolution path of granite reaction and both of these results agree well with the field data. In the reaction path modeling of rain watergranite/
anorthosite reaction, as a reaction is progressing, the activity of hydrogen ion decreases (pH increases). The concentrations of cations are controlled by the dissolution of rock-forming minerals and precipitation and re-dissolution of secondary minerals according to the pH. The continuous addition of granite causes the formation of secondary minerals in the following sequence; gibbsite plus hematite, Mn-oxide, kaolinite, silica, chlorite, muscovite (a proxy for illite here), calcite, laumontite, prehnite, and finally analcime. In the anorthosite reaction, the order of precipitation of secondary minerals is the same as with granite reaction except that there is no silica precipitation and paragonite precipitates instead of analcime. The silica and kaolinite are predominant minerals in the granite and anorthosite reactions, respectively. Total quantities of secondary minerals in the anorthosite reaction are more abundant than those in the granite reaction.

Keywords reaction path modeling, secondary mineral, rain water-granite/anorthosite reaction, groundwater evolution

Article

Econ. Environ. Geol. 2002; 35(1): 13-23

Published online February 28, 2002

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Estimation of Geochemical Evolution Path of Groundwaters from Crystalline Rock by Reaction Path Modeling

Kyu-Youl Sung1*, Maeng-Eon Park1, Yong Kwon Koh2 and Chun Soo Kim2

1Dept. Environ. Geosci., Pukyong National University, Busan 608-737, Korea
2Korea Atomic Energy Research Institute, Taejon 305-600, Korea

Correspondence to:

Kyu-Youl Sung

sungky@mail1.pknu.ac.kr

Received: December 3, 2001; Accepted: February 21, 2002

Abstract

The chemical compositions of groundwaters from the granite areas mainly belong to Ca-HCO3 and Na-HCO3 type, and some of these belong to Ca-(Cl+SO4) and Na-(Cl+SO4) type. Spring waters and groundwaters from anorthosite areas belong to Ca-HCO3 and Na-HCO3 type, respectively. The result of reaction path modeling shows that the chemical compositions of aqueous solution reacted with granite evolve from initial Ca-Cl type, via Ca-HCO3 type, to Na-HCO3 type. The result of rain water-anorthosite interaction is similar to evolution path of granite reaction and both of these results agree well with the field data. In the reaction path modeling of rain watergranite/
anorthosite reaction, as a reaction is progressing, the activity of hydrogen ion decreases (pH increases). The concentrations of cations are controlled by the dissolution of rock-forming minerals and precipitation and re-dissolution of secondary minerals according to the pH. The continuous addition of granite causes the formation of secondary minerals in the following sequence; gibbsite plus hematite, Mn-oxide, kaolinite, silica, chlorite, muscovite (a proxy for illite here), calcite, laumontite, prehnite, and finally analcime. In the anorthosite reaction, the order of precipitation of secondary minerals is the same as with granite reaction except that there is no silica precipitation and paragonite precipitates instead of analcime. The silica and kaolinite are predominant minerals in the granite and anorthosite reactions, respectively. Total quantities of secondary minerals in the anorthosite reaction are more abundant than those in the granite reaction.

Keywords reaction path modeling, secondary mineral, rain water-granite/anorthosite reaction, groundwater evolution

    KSEEG
    Jun 30, 2024 Vol.57 No.3, pp. 281~352

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