GEOTHERMAL SOLUTE EQUILIBRIA - DERIVATION OF NA-K-MG-CA GEOINDICATORS
GEOTHERMAL SOLUTE EQUILIBRIA - DERIVATION OF NA-K-MG-CA GEOINDICATORS
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DOI：
10.1016/0016-7037(88)90143-3
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发表时间：
1988-12-01
影响因子：
5
通讯作者：
GIGGENBACH, WF
中科院分区：
文献类型：
--
作者：
GIGGENBACH, WF
通过平均地壳岩石等化学再结晶得到的完全平衡的热流体中Na、K、Mg和Ca的相对含量在给定的温度和盐度下是唯一固定的。它们与岩石等化学溶解产生的水的组成一起，为评价流体-岩石平衡的达到程度提供了有价值的参考。在地热系统中，K-Na对达到平衡含量的速度最慢，为L kn= log (c K c Na)= 1.75−(1390 T) （c1单位mg/kg， T单位K）。根据L km= log (c 2 K c Mg)= 14.0−(4410 T)，商c 2 K c Mg调整得更快，并且适合低温（< 100℃）。系统K-Ca对fco2的变化敏感，lkc = log (c2kcca)= log fco2 + 3.0。这些子系统结合起来，通过使用地热水排放的Na、K、Mg和Ca含量，获得了评估深层温度和CO 2分压的图形技术。
Abstract Relative Na, K, Mg, and Ca contents of thermal waters in full equilibrium with a thermodynamically stable mineral system derived through isochemical recrystallisation of an average crustal rock are, at a given temperature and salinity, uniquely fixed. Together with the compositions of waters resulting from isochemical rock dissolution, they provide valuable references for the assessment of the degree of attainment of fluid-rock equilibrium. In geothermal systems, the pair K-Na reaches its equilibrium contents as governed by L kn= log (c K c Na)= 1.75−(1390 T) most slowly (c 1 in mg/kg, T in K). The quotient c 2 K c Mg adjusts much faster and to low temperatures (< 100° C) according to L km= log (c 2 K c Mg)= 14.0−(4410 T). The system K-Ca is sensitive to variations in f co2 with L kc= log (c 2 K c Ca)= log f co2+ 3.0. These subsystems are combined to obtain graphical techniques for the evaluation of deep temperatures and CO 2-partial pressures by use of Na, K, Mg and Ca contents of geothermal water discharges.