AUTHOR=Nicula Alin-Marius , Ionescu Artur , Pop Ioan-Cristian , Roba Carmen , Forray Ferenc L. , Orăşeanu Iancu , Baciu Călin 

TITLE=Geochemical Features of the Thermal and Mineral Waters From the Apuseni Mountains (Romania)

JOURNAL=Frontiers in Earth Science

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2021.648179

DOI=10.3389/feart.2021.648179

ISSN=2296-6463

ABSTRACT=<p>The Apuseni Mountains are located between the large geothermal area of the Pannonian Basin and the low thermal flux Transylvanian Basin. Thermal and mineral waters have been sampled from 42 points along a NW-SE transect. The general chemistry and the water isotope (deuterium and oxygen-18) composition were analyzed. Most of the thermal aquifers are located in carbonate reservoirs. The waters mainly belong to the Ca-HCO<sub>3</sub> hydrochemical type, excepting the western side, towards the Pannonian Basin, where the Na-HCO<sub>3</sub> type may occur. The isotope composition indicates aquifer recharge from precipitation. The geochemical characteristics and the structural position of the study area suggest two distinct geothermal contexts. The Southern Apuseni area geothermal features are likely connected to the Neogene—Early Quaternary magmatic activity from the Mureş Valley and Zarand Depression. The geothermal manifestations in the north-western part of the study area, at the border between the Northern Apuseni and the Pannonian Depression, share features of the latter one.</p>