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

Abstract

The origin and nature of the numerous lakes in the central Ebro Basin have been interpreted according to the prevailing arid or semiarid conditions, the easily-eroded materials and the solubility of the gypsum-and/or carbonate-rich Tertiary/Cenozoic substratum, involving important dissolution (karstic) and/or aeolian deflation. However, the origin of Sariñena Lake, the largest in the central Ebro Basin, remains unknown since the typical lake-generating processes in the region are not applicable. This work provides significant clues to the genesis and evolution of Sariñena Lake in a regional context. The combination of geomorphological mapping and high resolution LiDAR

Relict periglacial soils on Quaternary terraces in the Central Ebro Basin (NE Spain)

“…Collapses related to karstic processes in gypsum or limestones and volume changes associated with anhydrite expansion into gypsum cannot explain the deformities and fragmentation of soil horizons because the materials underlying the alluvial deposits are detrital, mainly lutite and sandstone, and there are no gypsum rock or limestones in the area. Similarly, expansion–retraction of clay‐rich materials may be rejected as no expandable clays have been found in this region …”

“…The remnants of terrace T6 correspond to the residual reliefs of Santa Cruz and Puyalón (Figure ). Previous work has proposed that this terrace previously impeded external surface drainage and occluded a low‐lying zone, thereby creating high water tables that influenced the development of piping processes in the surrounding sodium‐rich Miocene clays and the formation of Sariñena Lake …”

“…Previous work has proposed that this terrace previously impeded external surface drainage and occluded a low-lying zone, thereby creating high water tables that influenced the development of piping processes in the surrounding sodium-rich Miocene clays and the formation of Sariñena Lake. 29 Paleomagnetic data for the T5 terrace indicate a normal polarity and consequently an age younger than the Matuyama-Brunhes reversal at 781 ka BP. 18 The samples analyzed by IRSL dating provided ages of 235 ± 17, 196 ± 13 and 274 ± 18 ka BP.…”

“…The accumulations of Fe and Mn oxides together with the dissolution features on carbonate clasts in horizons with a high proportion of rock fragments indicate that the high transmissivity of these horizons may have favored their contact with a persistent water table with variable temporal saturation in calcite, in support of the hypothesis of a paleohydrological regime with a shallow water table in this area. This hypothesis is consistent with previous work regarding the formation of the Sariñena endorheic basin, which suggested that the T6 residual reliefs of Santa Cruz and Puyalón (Figure ) occluded a low‐lying zone in the western Sariñena high plain where a shallow water was available …”

“…Similarly, expansion-retraction of clay-rich materials may be rejected as no expandable clays have been found in this region. 29,35 Windthrow of trees has been shown to cause deformation and involutions in soils. 36 However, the involutions identified in the soils studied are sufficiently generalized spatially, and show a continuity, symmetry and depth that discard this possibility.…”