Combined effects of groundwater and aeolian processes in the formation of the northernmost closed saline depressions of Europe: north-east Spain

Abstract

Abstract:A genetic and evolutionary model is established for saline depressions in continental areas. These depressions are located in arid or subarid areas, and are developed on low permeability geological mediums (K 5 10 mm/ day) with a lack of streams reaching the small lakes. The phenomenon of evaporation is fundamental, since it is the basic requirement for the presence or absence of a free water surface in the lake, and also for depression of the phreatic surface, which causes in¯ow of groundwater towards the lake. With these conditions, the proposed model includes the following stages: (i) initiation of the close depression; (ii) deepening of the depression; (iii) formation of the lake basin and the end of the deepening; and (iv) levelling and lateral extension of the lake basin. The combined eects of groundwater¯ows and aeolian action oer a coherent explanation for the origin and evolution both of the closed depressions found in the Ebro Valley, and of the salt lakes that subsequently form. The processes described form morphologies of oval shape with the main axis parallel to the direction of the wind,¯at¯oors and evaporitic sedimentation, although they act on geological materials with dierent lithologies. #

Origin and evolution of Sariñena Lake (central Ebro Basin): A piping-based model

“…Most lacustrine depressions in the central Ebro Basin hold playas and saline lakes, whose geomorphic origin and evolution remains poorly understood (Gutiérrez et al, 2013). Lake genesis models applied to the region include the collapse of large bedrock cavities, widespread dissolution by groundwater and subsequent subsidence, and aeolian deflation during dry periods (Quirantes, 1965;Ibáñez, 1975;Sánchez et al, 1998;Gutiérrez et al, 2013). Sariñena Lake, one of the most important bodies of water in the Ebro Basin because of its size and volume, is difficult to explain using these models.…”

Soil properties across a hydrological gradient in saladas from northeast Spain: what are the implications for soil carbon stocks, CO2 efflux and microbial communities in a warming world?

“…The saladas have developed in an area of sub-horizontal Miocene siltstones, mudstones and ribbon or sheet sandstones and microconglomerates (sensu Friend et al 1979). Preferential weathering of the less resistant argillaceous strata has tended to give rise to the depressions, leaving some of the more resistant calcareous sandstone and microconglomerate bodies in positive relief in the form of sinuous, inverted palaeochannels on the salada margins (Sa ´nchez et al 1998;Gutie ´rrez et al 2005). All three saladas form part of a 7 km 2 Natura 2000 site (Saladas de Alcan ˜iz, site code ES2420114), which was designated because it is one of the most important endorheic areas on the Iberian Peninsula, with plant communities adapted to saline conditions and a rich fauna linked to seasonal inundation (European Commission, no date).…”

Changes In Soil Properties Across A Hydrological Gradient In Saladas From Northeast Spain: Implications For Soil Carbon Stocks, CO2 Efflux And Microbial Communities In A Warming World.

“…Across the central Ebro basin, the saladas are commonly found in depressions formed by physical weathering, dissolution, and aeolian de ation of ne-grained sedimentary rocks, principally siltstones, mudstones, gypsiferous units, and limestones (Sánchez et al, 1998;Castañeda et al, 2005;Gutiérrez et al, 2005). Consequently, many saladas are partially bordered by a bedrock escarpment or elevated ground and contain a central at area that is periodically inundated for varying durations (Domínguez-Beisiegel et al, 2013a).…”

“…The saladas have developed in an area of sub-horizontal Miocene siltstones, mudstones and ribbon or sheet sandstones and microconglomerates (sensu Friend et al, 1979). Preferential weathering of the less resistant argillaceous strata has tended to give rise to the depressions, leaving some of the more resistant calcareous sandstone and microconglomerate bodies in positive relief in the form of sinuous, inverted palaeochannels on the salada margins (Sánchez et al, 1998;Gutiérrez et al, 2005). All three saladas form part of a 7 km 2 Natura 2000 site (Saladas de Alcañiz, site code ES2420114), which was designated on account of being one of the most important endorheic areas on the Iberian Peninsula, with plant communities to adapted to saline conditions and a rich fauna linked to seasonal inundation (European Commission, no date).…”