Diagnosing Non-Meteorically Induced Variations in the Chemistry of Saline Springs of the Vrancea Seismic Area (Romania) |
| |
| Authors: | Horia Mitrofan Constantin Marin Alin Tudorache M?d?lina Vi?an |
| |
| Institution: | 1. “Sabba ?tef?nescu” Institute of Geodynamics of the Romanian Academy, J.L. Calderon str. 19-21, Bucharest, Romania
2. “Emil Racovi??” Institute of Speleology of the Romanian Academy, Calea 13 Septembrie 13, 050711, Bucharest, Romania
|
| |
| Abstract: | A monitoring operation conducted over more than seven years has been addressing chemical fluctuations displayed by several cool, low-discharge springs located close to the highly seismic Vrancea area (Romania). Those outflows compositions proved to be strongly controlled by binary, essentially isochemical mixing between a deep-origin brine and meteoric freshwater. By taking advantage of this particular setting, there have been constructed diagrams aimed at investigating how the groundwater-discharges Na–K–Mg geothermometric parameters fluctuated as a function of the chloride content (taken to be an estimator of the freshwater-induced dilution). We made use of the reciprocal algebraic relationships existing between the equations describing the Na–K–Mg geothermometric parameters “Na–K temperature” and “K–Mg temperature” on the one hand, and the so-called “maturity index” (MI) on the other. In an accordingly derived plot of MI against the logarithm of the chloride concentration, a series of data-points being quite uniformly off-set from the MI dilution-curve constructed for an apparently “regular” period, suggested that, episodically, all concerned springwaters were simultaneously subject to some similar changes in the controlling geochemical processes. One such modification intervened 3–4 months before the occurrence of the strongest earthquake ( \(M_{\text{w}} = 5.8\) ) of the hydrochemical monitoring period. The consequently derived interpretation was that then, the numerical values of certain geothermometric coefficients were likely altered: such a process could be consistent with changes in the alkali feldspars solubility relationships, possibly in response to episodic Al–Si complexing which might develop within a hypothesised, still active, exhumation-channel. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
