Jahani salt diapir, Iran: Hydrogeology, karst features and effect on surroundings environment

0480740 - GLÚ 2018 RIV IT eng J - Článek v odborném periodiku
Abirifard, M. - Raeisi, E. - Zarei, M. - Zare, M. - Filippi, Michal - Bruthans, J. - Talbot, J.
Jahani salt diapir, Iran: Hydrogeology, karst features and effect on surroundings environment.
International Journal of Speleology. Roč. 46, č. 3 (2017), s. 445-457. ISSN 0392-6672. E-ISSN 1827-806X
Institucionální podpora: RVO:67985831
Klíčová slova: salt diapir * brine spring * sinkhole * flow model * halite dissolution * salt karst
Obor OECD: Geology
Impakt faktor: 1.392, rok: 2017

The Jahani Salt Diapir (JSD), is an active diapir in the Simply Folded Belt of the Zagros Orogeny, in the south of Iran. The hydrogeology, schematic model of flow direction and hydrochemical effects of the JSD on the adjacent water resources are lacking, and thus, are the focus of this study. The morphology of the JSD was reevaluated by fieldwork and using available maps. The physicochemical characteristics of the springs and hydrometric stations were also measured. The vent of the diapir is located 250 m higher than the surrounding glaciers, and covered by small polygonal sinkholes (dolines). The glacier is covered by cap soils, sparse trees and pastures, and contains large sinkholes, numerous shafts, several caves, and 30 brine springs. Sub-horizontal or inclined stream passages following the surface valleys and vertical shafts (with short inlet caves) at the bottoms of nearly circular blind valleys. Salt exposure is limited to steep slopes. The controlling variables of flow route within salt diapirs are the negligible porosity of the salt rocks at depth more than about ten meters below the ground surface and the rapid halite saturation along the flow route. These mechanisms prevent deep cave development and enforce the emergence points of brine springs with low flow rates and small catchment area throughout the JSD and above the local base of erosion. The type of spring water is sodium chloride, with a TDS of 320 g/l, and saturated with halite, gypsum, calcite and dolomite. The water balance budget of the JSD indicates that the total recharge water is 1.46 MCM (million cubic meter)/a, emerges from 30 brine springs, two springs from the adjacent karstic limestone, and flows into the Firoozabad River (FR) and the adjacent alluvium aquifer. The FR cuts through the northern margin of the salt diapir, dissolving the glacier salts at the contact with JSD and increasing significantly the halite concentration.
Trvalý link: http://hdl.handle.net/11104/0276447