Upper Tagus loess formation and the marine atmosphere off the Iberian margin 
Paraiso section 
OSL ages SU 
[ka] _ 
4314 0.086 
2.23+0.03 
25.29 42.36 
Ta 
31.22412.40 
” pedagenic = 
organic carbonate total = Fo(dyFeft) 
content (7) content (90) ‘ron (g/kg) 
11_02 03 04 05 9_10 20 9 15 70 015025 0% 
= 
a 
ur 
>. 
30.49 42.43 
42.96 + 3.76 
42.53 + 3.56 
j 
4-3 
2 
50.69 + 4,71 
54.11 + 6.03 
06.31 + 10.32 
96.53 + 7.90 
lolat content 
COare sikt-sized 
Zarbonale content 
Figure 6. (color online) Stratigraphic sequence and analytical data for the Paraiso section (40°01’51.07’N’, 03°28’01.70”W; 556 m asl), show- 
ing OSL dating results, sediment units (SU), sampling points, palaeo surfaces (PS), and grain-size parameters (soil texture %, coarse silt con- 
tent % sand content %), organic content, carbonate content (total and coarse silt-sized fractions), and ratio between pedogenic and total iron as 
a weathering index. For legend, please see Figure 2. 
BR dissolved during 
1yoSUM eliminalian 
15 
15 2 25 3 36 fe. fine sand (Z00-63um) 
PS) — ms: medium sand 
(20-200um / <Z20um) {630-200um1 
ı reddish coloring and a concentration of fine calcified roots 
below (found at —2.6-m-depth at Villarubia and 3-m-depth 
at Paraiso), and fine sand together with PSI reaches maximum 
values in this part of the section. Likewise, the uppermost part 
of SU-7 (PS-5) shows more reddish-ochre colors, calcified 
roots, and macro biospurs (g 4 cm), decreasing values of 
cotal iron content, and very low clay contents. Finally, these 
more-reddish layers may again indicate a prolonged period 
of surface stability and exposure linked to an interruption of 
loess deposition without the initiation of major soil-forming 
processes. 
as 30%. Apparently, the location closer to the sediment 
source was responsible for the high sand peaks, indicating 
very short transport distances during wind gusts. The top 
of SU-8 reveals a sharp erosion discordance in the Parafso 
section that hampers the estimation of its original 
.hickness. 
Unit SU-9 marks the final loess deposition phase that 
only appears in the Fuentiduefia and A3 sections located 
closest to the Tagus River floodplain (Figs. 1, 8). It con- 
sists of light reddish-ochre and partly relocated material as 
seen in its slightly higher contents of medium and coarse 
sand. 
Upper part of the sections (SU-8 and SU-9) 
Sediments of SU-8 are distinguished from those of SU-7 
pased on individual geochemical properties (Figs. 9, 10) 
hat indicate the presence of two separate loess deposition 
phases. Higher contents of clay, fine silt, and medium silt 
cause a strong decrease of the PSI to values below 1.7 
{Figs. 2, 6). An exception is section A3 that is located 
very close to the recent Tagus River. Here, SU-8 consists 
of silty sand layers with silt contents in some layers as low 
Colluvial cover (SU-10) 
Except for Fuentiduena, all sections are topped by a colluvial 
deposit (SU-10) comprised of pale reddish and grayish ochre 
material with pebbles up to 2 cm in diameter and light, silty 
Jands that represent washing surfaces linked to erosion pro- 
cesses. The lower boundary is sharp and undulating and 
reveals a blackish fringe, probably indicating burning by 
fire (Fig. 6). The material is strongly enriched in organic 
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