Sedimentary response of lake El Tobar, Spain, to climate: lake level changes after the Maunder Minimum

Abstract

Lake level reconstructions from a littoral core in lake El Tobar, Spain, are presented for the last 350 years. These are based on plant macrofossils and stable isotopes from lacustrine carbonates. Our data suggest five episodes of advance and regression of the shoreline coupled with changes in water retention in the lake. A low lake level and high water renewal episode at ca. AD 1650–1715 is indicated by oxidized facies with abundant remains from terrestrial/marsh plant macrofossils and low d18O and d13C values. A fluctuating lake level episode at ca. AD 1715–1772 during changing climatic conditions in the Little Ice Age (LIA) caused periods of erosion and sediment deposition that intermittently blocked the lake outlet, resulting in more positive d18O and d13C values. The lake became progressively more closed with increased level in the wet years at the end of the LIA (ca. AD 1772–1850). During the Dalton Minimum, d13C values reached a minimum, indicating low productivity, but increased after this with development of submerged Chara. From ca. AD 1850 to 1960 lake levels were high but are marked by changes in marsh communities, mainly the shift from Juncus to Typha (ca. AD 1850–1960) predominance, which indicates low and high levels, respectively

Little Ice Age, Palaeofloods and human adaptation on the Jarama River (Tajo Basin, Central Spain) from documentary proxy data

“…The former group has a relatively lower abundance of floods detected in the Jarama valley compared with those of the other three groups, which are concentrated in a smaller number of years. Despite the fact that this group appears to coincide with intense cold in the Iberian mountains (González-Trueba et al, 2008;García-Ruiz et al, 2014;Gómez-Ortiz et al, 2018), the smaller number of floods might also be consistent with the dry period between 1650 and 1715 (Domínguez-Castro et al, 2010;López-Blanco et al, 2016). There is a higher degree of coincidence between the Dalton Minimum and a period of abundant floods in the Jarama valley, which is in agreement with the abundant floods and precipitation in Andalucía (Rodrigo et al, 2008;Rodrigo, 2018), Cataluña (Maldá anomaly), (Barriendos and Llasat, 2003) and the Tagus River (Benito et al, 2003).…”

Dry and wet periods over the last millennium in central-eastern Spain - a paleolimnological perspective

“…The radioisotopic activity of 210 Pb and 137 Cs published in López-Blanco et al (2011) and López-Blanco et al (2016b) shows very different sedimentation rate in the central and littoral parts of lake El Tobar. TOB04-1B and TOB07-4A only covered the previous 60 years while TOB-10 dated back the last 350 years.…”

“…Evaporation is higher during arid conditions, and authigenic lake carbonates are enriched in 18 O. During wetter periods the situation reverses, and the δ 18 O of the lake water reflects the (Ortega et al, 2015) and phases of transgression and regressions in the shore line of Lake El Tobar (López-Blanco et al, 2016b); 4) Comparison of the inferred lake level in El Lagunillo with the NAO reconstruction (Ortega et al, 2015); 5) Charcoal signal (in charred particles/cm 3 .yr) in El Lagunillo and El Tobar. Note that all the normalization was done by using the mean and standard deviation.…”

Spatial variability of northern Iberian rainfall stable isotope values: Investigating climatic controls on daily and monthly timescales

“…The overall aim is to characterize and quantify the dominant factors modulating  18 O p variations in time (daily and monthly) and space, to determine the causes of precipitation isotopic variations regionally. Additionally, this study will serve to improve the interpretation of oxygen isotope paleorecords from the region that depend on  18 O p (Bartolomé et al, 2015;Domínguez-Villar et al, 2017;López-Blanco et al, 2016;Pérez-Mejías et al, 2019;Sancho et al, 2018Sancho et al, , 2015.…”

“…Treble et al, 2005),. As a consequence, paleoclimate proxies are often interpreted without a clear knowledge of the processes involved in modulating  18 O p at a particular region (López-Blanco et al, 2016;Moreno et al, 2017). It has long been established that  18 O p is an integrated product of air masses history , modulated by specific prevailing meteorological conditions (air temperature and amount of precipitation for example) (Craig, 1961;Dansgaard, 1964).…”