Upper Tagus loess formation and the marine atmosphere off the Iberian margin 
Another area of the Southern Meseta, specifically the upper 
catchment of the Guadiana River south of the Montes de 
Toledo (Fig. 1), is characterized by having had less intense 
surface erosion during the late Quaternary due to a higher 
local base level of erosion. Here, the wetlands of the upper 
Guadiana River represent a valuable Late Pleistocene archive 
that is being intensively researched (e.g., Santisteban et al., 
2019). The sedimentary record of the Fuentillejo maar lake 
in the volcanic field of Campo de Calatrava (Ortiz et al., 
2013) shows evidence of environmental fluctuations corre- 
sponding to D-O cycles. More specifically, Vegas et al. 
2010) found cold and ariıd conditions related to HE 2, 
HE 1, and the Younger Dryas, whereas HEs 3-5 were 
assumed to relate to rather warm and arid conditions. How- 
ever, relatively low chronological resolution was the limiting 
factor here. Finally, there are numerous playa lakes in the 
Southern Meseta (Schütt, 2000). However, due to high salin- 
ity and frequent desiccation events, these lake sediments 
revealed a limited potential in recording last glacial paleoen- 
vironmental evolution. 
From this, it follows that reliable information about the 
effect of marine cold spells linked to stadial phases on geo- 
morphological systems in central Iberia is lacking, even 
more if stadials comprising HEs (HS) are considered. 
Hence, there is a need for systematic studies on fluvial, aeo- 
lian, and glacial sedimentary archives relating to relevant 
past earth surface processes. In order to meet this need and 
(O verify whether Greenland stadials as well as Heinrich sta- 
dials exercised a decisive influence on geomorphological sys- 
;ems, we undertook comprehensive studies on loess deposits 
in the upper Tagus Basin to obtain a more complete picture of 
late Pleistocene landscape dynamics in central Spain. Besides 
a general evaluation of phases linked to loess deposition and 
surface stability, we used a broad multi-proxy approach in 
order to accurately characterize hydrological conditions, pale- 
otemperatures, and wind strengths during the last glacial 
period. 
METHODS 
Stratigraphic work 
In total, five loess sections were included in this study in order 
to obtain a representative composite profile for the last glacial 
period (Fig. 1). All sections were analyzed in the field, includ- 
ing differentiation of sedimentary units, the presence of pale- 
0sols or processes indicating soil formation, and evidence for 
relocation processes. We took samples from all sections for 
laboratory analyses. In general, sampling was oriented 
towards stratigraphic layers with the aim of providing a repre- 
sentative record of all dynamic phases during the last glacial 
period. On average, samples for standard analyses were taken 
at 15 cm intervals from all sections. We took 28 samples for 
heavy mineral analyses from each layer in three sections 
(Fuentiduena, Paraiso, and A3). We also took seven samples 
from surrounding areas (for more details, see Wolf et al., 
2019). The same three sections sampled for heavy mineral 
analysis were also chosen for luminescence dating on 25 sam- 
ples. The most complete section (Paraiso) was sampled for 
n-alkane biomarker analyses and stable isotope measure- 
ments, with 25 samples with an average sampling density 
of 25 cm taken. 
Standard analyses 
Srain-size determination was conducted by pipette analyses 
and wet sieve techniques (Schlichting et al., 1995) after dis- 
Jersion with sodium pyrophosphate. Because samples con- 
:ained gypsum that disrupted the settling process in the 
sample cylinder by flocculation, all samples were passed 
hrough a repeated cycle of dissolution and centrifugation 
ıntil measured electrical conductivity fell below a value of 
100 uS cm” (Frenkel et al., 1986). For determining 
fraction-specific carbonate contents for different grain-size 
classes, we conducted grain-size analysis twice, with a first 
un implemented without decalcification, and a second run 
after carbonates were dissolved using 10% HCl. Following 
his procedure, a particle size index (PSI) was calculated 
3ased on samples that were not decalcified by forming a 
:atio between the coarse silt/fine sand fractions (> 20 um 
ınd < 200 um) and all finer fractions, including medium 
silt, fine silt, and clay. The calcium carbonate content was 
determined by measuring the carbon dioxide gas volume 
after adding hydrochloric acid in a Scheibler apparatus 
‘Schlichting et al., 1995). Soil organic matter was measured 
via suspension and catalytic oxidation (TOC-VCPN/DIN 
[SO 16904). Total iron content (Fe(t)-values) was determined 
after pressure digestion with concentrated nitric and hydroflu- 
oric acid using atomic adsorption spectrometry (Analytic 
Jena, Vario 6). Pedogenic iron content (Fe(d)-values) was 
neasured after dithionite extraction using atomic adsorption 
spectrometry (Schlichting et al., 1995). The ratio between 
nedogenic and total iron may provide information of the 
intensity of weathering, and thus may indicate soil formation 
in the case of higher values in comparison to the parent 
material. 
Micromorphological analyses 
For micromorphological analyses, 18 oriented and undis- 
urbed samples were collected from selected horizons of the 
sequences at Paraiso and Fuentiduena. Vertical thin sections 
were prepared at the Laboratory of Soil Science and Geoecol- 
ogy at the Institute of Geography, Eberhard-Karls-University, 
Tübingen. Thin sections were then analyzed and photo- 
zraphed using a polarizing microscope (Zeiss Axiovision). 
Thin section descriptions mainly are based on the terminol- 
ogy after Bullock et al. (1985) and Stoops (2003). 
Age determination: luminescence dating 
Optically stimulated luminescence (OSL) measurements 
were applied to the coarse-grained quartz fraction (90-200 
um). Following standard procedures (e.g., Fuchs et al., 
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