Landwards of a MIS5 bar, a borehole core (SRA) was analyzed to establish the relationship between the lagoonal record and the raised beach deposits in the surroundings of the Antas river mouth and to reconstruct the Pleistocene palaeoenvironmental evolution of the southern Mediterranean coast of the Iberian Peninsula. 63 samples were recovered for amino acid racemization dating, 86 samples for sedimentological and paleontological determination, 37 samples for pollen identification and 54 for biomarker analysis. AAR revealed that the borehole record contains MIS11, MIS6 and MIS5 deposits, the latter extensively represented. During the end of MIS6 and MIS5, a sand barrier developed and created a shallow lagoon with alternating terrestrial inputs this process being common in other Mediterranean realms. Litho- and biofacies allowed the identification of distinct paleoenvironments through time, with the presence of a lagoonal environment alternating with alluvial fan progradation. Biomarkers indicated constant input from terrestrial plants, together with variable development of aquatic macrophytes. The palynological content allowed the reconstruction of the paleoclimatological conditions during MIS6 and 5, with evidence of seven scenarios characterized by alternating arid and relatively humid conditions.
In many areas of the Mediterranean coast – Spain, Morocco, Tunisia – the current morphology appears as a series of cliffs where Alpine tectonics-linked parallel ranges reach the sea alternating with lagoons and wetlands. Some of the Quaternary coastal deposits of the Spanish Mediterranean realm have been studied, mostly focusing on raised marine deposits and addressed faunal remains and radiometric ages (Goy et al., 1986; Hillaire-Marcel et al., 1986; Causse et al., 1993; Zazo, 1999; Zazo et al., 2003; Dabrio et al., 2011) and amino acid chronology (Hearty, 1986, 1987; Hearty et al., 1986; Torres et al., 2000a, 2010a; Ortiz et al., 2004a). Unfortunately, raised marine deposits offer limited paleoenvironmental information because their coarse-very coarse grain size does not allow the preservation of most paleobiological (pollen, ostracods and foraminifers) and geochemical (biomarkers) signals.
Other authors have examined the lagoonal records (Collado and Robles, 1983; Usera et al., 2002, 2006; Ferrer et al., 2005; Blázquez and Usera, 2010; Ferrer y Blázquez, 2012) and pollen content of continental sequences (Pérez-Obiol and Julià, 1984; Fumanal and Dupré, 1986; Burjachs and Julià, 1994; Yll et al., 1994; Badal and Roiron, 1995; Carrión and Dupré, 1996; Carrión and van Geel, 1999; Carrión et al., 1999).
In this regard, the lagoonal record in the Antas river mouth area and associated raised marine deposits provide an interesting system to establish methodological work which allow the understanding of high stand sea level deposits through-time evolution in the Mediterranean realm, especially MIS5.
The Mediterranean coastline between the mouths of the Aguas and Antas rivers
has not been examined in detail. A number of raised marine deposits were
previously sampled for the determination of a regional amino-stratigraphical
framework (Torres et al., 2000a, 2010a). The lagoonal deposits that outcrop
in this area have been studied by Pantaleón-Cano et al. (2003), who
analyzed the pollen content, but the bizarre
Coastal marshes and mires, most representing the last evidence of the satellite basins that developed after the Alpine Orogeny Period, hold the best preserved paleoenvironmental signals. Lagoonal and marsh deposits appear along the Spanish Mediterranean coast in Peñíscola (Usera et al., 2006), Torreblanca (Collado and Robles, 1983; Segura et al., 1997), Almenara (Blázquez and Rodríguez-Pérez, 2013), Jávea (Fumanal et al., 1993; Usera et al., 2002), Gandía and La Safor (Viñals, 1995a), Moraira (Viñals, 1995b), Albufereta-Alicante (Ferrer et al., 2005, Ferrer y Blázquez, 2012), and Roquetas de Mar (Pantaleón Cano et al., 2003). However, all these deposits have short sequences covering the Holocene. While longer Pleistocene sequences appear in the Elche Basin (Blázquez, 2005, Blázquez and Usera, 2010) and Pego Basin (Dupré et al., 1988; Mateu, 1989; Viñals et al., 1989; Hernández-Ruiz et al., 1993; Viñals and Fumanal 1995; Viñals, 1996; Mateu et al., 1997; Torres et al., 2013), sequences belonging to MIS5 are present as loosely cemented sands. Consequently, the core recoveries are low and the grain size is not favorable for paleoenvironmental recording.
We therefore considered this deposit suitable for interpreting the paleoenvironmental evolution of the southern Mediterranean coast of the Iberian Peninsula. The aims of this study were as follows: (1) to establish the chronological framework through amino acid racemization dating of the lagoonal deposits (SRA core); (2) to obtain paleoenvironmental information based on sedimentology and micropaleontology of a long MIS5 sequence; (3) to determine regional plant biomes and paleoclimatic variations based on pollen data; and (4) to address the biomes of the area by interpreting the biomarkers contained in the sediments.
The SRA borehole was drilled in the Vera Basin, which is an inverted basin (Stokes, 2008) in the Internal Zone of the Betic Cordillera. The Garrucha village is placed on a hill slope capped with beach deposits of Pleistocene age lying uncomfortably on quasi-azoic Pliocene delta sediments. The western side of the village ends abruptly due to a vertical cliff, which falls on a flat, almost endorheic, depression – El Salar – in which saline muds accumulate during flash-flood episodes that the Antas river cannot drain, as occurred on 28 September 2012.
This area around the mouths of the Aguas and Antas rivers hosts a series of Pleistocene-age marine deposits that mark the eastern edge of the marine Vera Basin (Fig. 1), which can be age-correlated in spite of they were subjected to strong neotectonic processes (Torres et al., 2000a, 2006, 2010a, 2013).
In fact, in the immediate neighborhood of the SRA, a stripe representing an
ancient barrier system (MIS5) and running parallel to the present day
coastline is clearly visible in Fig. 1. This stripe consist of gravel and
coarse sands that are strongly carbonate-cemented, and should protect the
lagoonal area of SRA during MIS 5. These materials appear as foreshore
dipping beds some decimeters thick. At some points, a number of beds dip
backshore. Scattered
The area is placed in the “almeriense” sector of the “murciano-almeriense” chorological province (Rivas Martinez, 1988). The native plant species are resistant to drought and aridity, which occur during the summer and also in some winter-autumn months. Thus plant species have xerophytic characteristics, thus largely exposing soil and bed rock (Ferré Bueno, 1979).
The natural vegetation in the Almanzora valley falls in the climatic
dominion of
In the western-most sierras, a variety of the
All these series showed profound degradation, which is linked to industrial activity (mining and metalworking industry), agriculture, and grazing (Rodríguez Ariza, 1999).
The sampling work focused on the SRA of the Antas river (Fig. 1). This borehole was drilled for geotechnical studies on the right margin of the river, near its mouth, where the river incises 3.5 m into soft materials.
Ten kilometers upstream of the Aguas river mouth, the tufa deposits from
Alfaix (ALF) outcrop. These were used only to check the results obtained in
SRA. The tufa deposits consist of a 23 m thick sequence (Schulte et al.,
2008), the bottom of which is 7 m above the present day Aguas river thalweg.
Using U/Th dating, these authors dated the lowermost 13 m (approx.) of the
sequence at 169
To establish the chronology of the SRA record, we selected ostracod shells as they provided excellent results in former studies (Ortiz et al., 2004b, 2009). Similarly, ostracods were also sampled in three levels of the Alfaix fluvial terrace.
Ostracod specimens from various species were recovered, although only
Ostracod valves were cleaned sonically in distilled deionized (DDI) water
and rinsed in the same water to remove sediment. Some valves were also
cleaned with a small brush under a binocular microscope to eliminate fine
debris. In order to remove secondary organic molecules adsorbed to the
shells, the valves were then submerged in 3 % hydrogen peroxide
(H
Amino acid concentrations and ratios were quantified using HPLC, following
the sample preparation protocol described by Kaufman and Manley (1998) and
Kaufman (2000). This procedure involves sample hydrolysis, which was
performed under an N
Derivatization took place before injection by mixing the sample (2
For the age calculation of SRA and ALF samples, aspartic acid and glutamic
acid were chosen because they account for over ca. 50 % of the amino acid
content in most ostracod valves (Kaufman, 2000; Bright and Kaufman, 2011).
The numerical age of each bed was determined by introducing the aspartic
acid and glutamic acid D/L values obtained in
We used the age calculation algorithms obtained in ostracods collected in
central and southern Spain by Ortiz et al. (2004b) for the dating these
deposits because a similar thermal history can be inferred for these areas,
as they are all located in the Mediterranean climatic zone of the Iberian
Peninsula, with a similar mean annual temperature. Likewise, the age
calculation algorithms were established for the ostracod species analyzed
here (
A total of 86 samples at 20–30 cm intervals were picked from the borehole core. These samples were analyzed for sedimentological, micropaleontological (especially, ostracoda and foraminifera) and palynological studies. The sampling interval was chosen on the basis of major changes in sediment color, grain size, and the presence of chemicals (gypsum crystals), and macrofossils.
Totally dried samples were gently crushed, soaked, passed through a 62
A total of 37 samples were selected for palynological analysis. Pollen was extracted following standard protocols (Couteaux, 1977; Faegri et al., 1989; Girard and Renault-Miskovsky, 1969; Moore et al., 1991). The residuals were pollen-enriched through flotation in Thoulet's dense liquor (Goeury and Beaulieu, 1979) and later placed in Eppendorf tubes and preserved in glycerin.
Pollen grains were read and counted following Cambon (1981): 42 rows in each sample. The number of pollen grains in the samples oscillated between 110 and 716, although in some samples the number was so low (10–20) that they appeared in the pollen diagram as “presences”. In these cases the number of identifiable taxa was greatly reduced (5 or lower).
Statistical analysis was done using the package OLEA (M. Arroyo unpublished), which is based on philosophy of the TILIA® and TILIA-GRAPH® (Grimm, 1987, 1992) packages.
In the samples with a statistically significant number of pollen grains, we built AP/NAP logs and analyzed the rarefaction (Birks and Lyne, 1992) to determine vegetation diversity.
In order to facilitate the interpretation of the data, we built a synthetic
pollinic diagram, which included the most significant taxa (
Finally, all the sampled were subjected to a PCA (Principal Component Analysis) using the Biplot application from Excel-Microsoft.
A total of 54 samples were collected for biomarker analysis, coarse-grained
sediments being discarded. 5 g of sediment per sample was dried at
50
The isolated lipid extract was concentrated to dryness using a rotary
evaporator, then methlylated with trimethylsilyldiazomethane and methanol
for 20 min and evaporated with nitrogen. Samples were redissolved in 1 ml of
dichloromethane prior to analysis by gas chromatography (HP 6890) with a
mass selective detector (HP 5973) equipped with an ATM-5 column (250
The D/L values of aspartic acid and glutamic acid in the ostracod samples
from the Alfaix tufa terraces and the SRA borehole are shown in Table 1. The
ages obtained in the former were coincident with those reported by Schulte
et al. (2008) using U/Th dating (169
SRA ages, in agreement with Alfaix U/Th-dated tufa deposits, totally
differed from the ages described by Pantaleón-Cano et al. (2003) for the
lagoonal deposits of the mouth of the Antas River, namely: 8690
The possibility of ostracod reworking from older deposits is unlikely
because the shells were not eroded, in some cases still being articulated.
Furthermore, in some samples ostracods were found together with juvenile
thin-shelled
The AAR dating of the SRA record allowed us to determine that MIS11 (a single dating was obtained), MIS6 pro-parte, and MIS5 are represented. As the ages showed an uncertainty of about 25 %, the MIS5 sub-episode boundaries were refined on the basis of the palynological analysis and paleoenvironmental information derived from sedimentology. This implies that MIS6-MIS5e was displaced 80 cm upwards, and we were unable to differentiate between MIS5b and MIS5a.
The SRA core comprised mainly material of detrital origin, predominantly clay, silt, and marls (Fig. 2). Six lithologies were observed:
Gm: Gravel Gf: fine-grained gravel ( Sl: laminated medium-coarse grained quarzt sands, with metamorphic rock fragments. In outcrops, ripples and scattered charcoal fragments are visible. This is the only portion of the record visible on outcrops. Fs: carbonated sandy lutites (silt), with scarce scattered sand grains, locally iron oxide-stained. Fm: massive lutites (clay), with small amounts of fine-grained sand. Mica flakes are abundant. Mg: white-gray marls with lenticular and tabular gypsum crystals, limonitized plant stems and carbonate-cemented tubuli (plant roots?).
The mineralogy of the fraction coarser than 62
Many samples contained foraminifers, with the exception of the following
levels: 2300, 1780–1600, 1330–1240, 790, 1120–850 cm. We separated the
foraminifera species into two assemblages: autochthonous and allochthonous
associations. The former holds indigenous specimens while the latter
indicates reworked tests from older strata (Pliocene). Most of the samples
including foraminifers showed the allochthonous association. Only levels
2300, 1850, 1390–1360, 1180, 820, 700, 300–240 cm contained autochthonous
foraminifers, the following being common:
The allochthonous association comprised planktonic (
This association was present between 2960 and 2840 cm, but foraminifer tests did not show evidence of reworking and therefore could be dated as Pliocene.
A large number of ostracod valves were recovered from almost all the
samples, the presence of
Mollusks were scarce in the SRA and limited to levels 1390–1330 cm, in
which
Lagoons and marshlands receive organic matter from autochthonous (phytoplankton, bacteria, aquatic macrophytes) and allochthonous (terrestrial plant debris, pollen) sources. Consequently, palaeoenvironmental changes are reflected in the biogeochemistry of sediment records (Meyers and Ishiwatari 1993; Meyers 1997, 2003). However, the interpretation of organic geochemical signals is not always straightforward because in most cases organic matter is a mixture of components from many sources and with variable degrees of preservation.
The logs of the various indexes related to the
The SRA cores samples showed
The ACL (Poynter, 1989), calculated as [(C
The Paq index, calculated as the (C
Silliman et al. (1996) reported that the terrigenous
The
Pollen was not present in the lowermost (2850–1830 cm) or uppermost (280–0 cm) part of the SRA record.
In the samples from the remaining record, we identified 39 taxa, of which 11
were trees (
The pollen assemblage reveals a Mediterranean climatic scenario with fluctuations of moisture and, in some intervals, mainly in the upper half of the section, the presence of Nitrophilous taxa.
The pollen diagram (Fig. 4) reveals that tree cover was denser in the lower part of the record and more open at the top. Similarly, the shrubby stratum did not contribute greatly to the vegetation structure nor did NPM, aquatic taxa, or most of the elements identified in the trees or grasses groups.
Given the above observations, we built a synthetic diagram taking in
consideration various taxa (
We differentiated the following five lithological units in the SRA borehole on the basis of sedimentological characteristics and microfossil content (Fig. 2): Unit I (29.7–28.2 m: Pliocene yellow-grey marls and silts; Unit II (28.2–24.2 m loosely cemented gravels interbedded with sands of Pleistocene age); Unit III (24.2–18.2.2 m loosely cemented Pleistocene gravels and sands); Unit IV (18.2–3.0 m variegated lutites with bioclasts and gypsum); and Unit V (3.0–0.0 m laminated fine-grained sands). Because of some minor variations in lithology and biological content, Unit IV was sub-divided in ten (a–j) sub-episodes.
Although Pantaleón-Cano et al. (2003) identified these units in their borehole record, they observed peat deposits between 22.50 and ca. 20.60 m that were not present in the SRA core. Those authors did not provide the coordinates of their borehole, however, this discrepancy allows us to conclude that SRA and Pantaleón-Cano et al. (2003) boreholes were drilled in different areas of the paleo-lagoon.
Each sedimentary unit corresponded to a certain environment (Table 3, Fig. 2). With the exception of marine conditions that occurred during the Pliocene, the basin showed evidence of alluvial fan progradation alternating with lagoonal and palustrine episodes. The alternation of these cycles was especially common during MIS6 and 5, reflecting environmental changes that do not necessarily coincide with climate changes inferred from the palynological interpretation. These deviances can be explained by offset between climate and sedimentological response.
Thus, the Pleistocene record of the SRA borehole was deposited during two periods (Table 3, Fig. 2): the lowermost sands belonging to Units II and III corresponded to MIS11, whereas the lutites of Unit IV (uppermost 16 m) belonged to the end of MIS6 and MIS5, the latter fully recorded. The stratigraphical hiatus corresponding to the MIS11-MIS6 period explains the distinct geomechanical characteristics of the two deposits (cemented and compacted vs. uncemented and water-soaked). These units can be correlated with beach and bar deposits of the same age.
During MIS11 alluvial fan conditions were predominant in the Vera Basin. Thick massive gravels in the lower half of the record, followed by silts with short palustrine episodes (autochthonous ostracods) can be identified as fan toe sediments. We were unable to determine othe paleoenvironmental conditions because of the lack of pollen grains.
No marine record from MIS6 was found on land, but marine geology mapping (Díaz del Río and Fernández Salas, 2005) of the area revealed a long, wide strip of coarse sand at a depth of 60–70 m, which may represent an undated lowstand system track LST (MIS6?).
We consider the AAR ages obtained for the MIS6 deposits feasible. The lower half of the record identified the margin of a playa lake which, in the upper half, changed to the red-brown silty sediments of a mud flat. According to the pollen record, the playa lake deposits correspond to dry-cold (relatively) conditions followed by humid and temperate-warm ones. During the deposition of the mud flat, cool and dry conditions dominated. Although MIS6 showed markedly unfavorable climatic conditions, as in other areas of southern Iberia, this period was a “climatic amelioration” when compared with MIS5.
A short description of the
The predominance of the C
The variations in Average Chain Length (ACL) values were small, although
some clarifications can be made. In this regard, the ACL values oscillated
between 21.9 and 28.0, implying a reduced contribution of low molecular
weight
The dominance of organic matter derived from terrestrial plants over algae
input can also be interpreted from the TAR
The Paq values were originally defined and used to determine the relative
contribution of macrophyte taxa and terrestrial plants to some African lakes
(Ficken et al., 2000). According to Ficken et al. (2000), Paq values under 0.1
are linked to a dominant contribution from land plants, while values between
0.1 and 0.4 reflect significant inputs from emergent macrophytes. Paq values
higher than 0.4 are typical in sediments with a major
In agreement with the lowest ACL values observed in the lower half of the record (Units II, III and sub-units IV a–b), Paq values were between 0.1 and 0.26, suggesting a considerable contribution of emerging macrophytes. In contrast, in the upper half of the record, most of the samples showed Paq values lower than 0.1, linked to terrestrial plants, with the exception of five excursions to higher values linked to a major input from emerging macrophytes (samples from 970, 910, 790, 520 and 300 cm). Episode V showed a greater terrestrial input, which can be explained by its alluvial character, with floating terrestrial plant debris still visible at the incised river banks.
The relative percentage of C Although the record showed grass dominance, three dominions were clearly
differentiated: Episode II to Episode IV-b (2840–1360 cm) showed a
saw-tooth distribution with a maximum-minimum range of 10 %. Between sub-episodes IV-c and IV-h the relative percentage of C Sub-episode IV-j and Episode V showed oscillating lower values of the
index.
Analysis of the evolution of the pollen frequencies allowed us to distinguish seven (I-VII) climate-related phases in the synthetic diagram (Fig. 5). Unfortunately, due to a lack of pollen grains in sediments belonging to MIS11, paleoenvironmental conditions could not be established.
In Phase I (1850–1700 cm), the pollen content was low, although
Phase II (1700–1550 cm) began with a sharp decrease in the presence of
In Phase III (1550–1330 cm), there was a clear dominance of
In Phase IV (1330–1120 cm), there was a clear expansion of Mediterranean
taxa, with some oscillations, together with an increasing presence of Xeric
and Steppic taxa, as well as
In Phase V (1130–840 cm), Mediterranean and Mesophilous taxa clearly
dominated, though with some oscillations. There was a clear decline in the
presence of
Phase VI (840–700 cm) started with an increase in
In Phase VII (700–290 cm), the presence of
To interpret the pollen assemblages, we performed a principal components
analysis (Fig. 6) on the data used for the synthetic diagram. Component 2
(explaining 56.55 % of the variability) grouped samples on the basis of
the development of the local Mesophilous and Mediterranean taxa (positive
values) versus open landscapes and regional
According to these results, cold-to-temperate and humid conditions developed during MIS6, coinciding with the paleoclimatological interpretation of the Fuentillejo core (Ruiz Zapata et al., 2012), located 300 km north-west of the SRA borehole in the same climatic zone (Fig. 1), as well as with the growth of tufa deposits in the Iberian Peninsula (Torres et al., 2005; Ortiz et al., 2009). In contrast, warm and arid conditions occurred at the end of MIS6 (140–133 ka) both in the Fuentillejo (Ruiz Zapata et al., 2012) and SRA cores.
At the beginning of MIS5 climatic conditions were warmer but less dry, with
the recovery of the Mediterranean forest, Mesophilous taxa and
During the rest of MIS5, the alternation of
Thus the palynological data revealed that paleoenvironmental fluctuations were not as extreme as in other areas of the Mediterranean realm and Central Europe.
The abundance of the ostracod
It was proved a clear relationship between the
On the basis of the lithology and sedimentological characteristics, we distinguished six associations of lithofacies, corresponding to lagoon deposits and distal alluvial fan influence.
Organic geochemistry, namely
Sedimentation during MIS11 was partially represented by alluvial fan sediments (Unit II) that retracted towards its end (Unit III). Unfortunately, we were unable to interpret the paleoclimatic conditions because the record was devoid of pollen content.
The end of MIS6 was confidently dated and represented by playa-lake marginal deposits (subunit IV-a). Towards the end of MIS6, the alluvial system was reactivated, as reflected in fine gravel and sand deposition (subunit VI-b). Frequent root tubuli indicate aerial exposure. The pollen content analysis revealed that this stage showed milder climatic conditions (warm-temperate) than the beginning of MIS5e (cool), although varying from dry to humid.
MIS5 was confidently dated and presumably all the sub-stages were represented, although AAR ages showed some uncertainties. During MIS5 a series of three lagoon-alluvial couplets were identified through sedimentological characteristics and the micropaleontological content. The lagoonal episodes were marked by the presence of autochthonous foraminifers and brackish-water mollusks and ostracods, the presence of which indicates larger marine ingressions during the MIS5e substage. Although these marine conditions never prevailed, as the lower presence of algae biomarkers suggest, the environment was characterized by intermittent sea-water entrance and emergent macrophyte colonization but with dominant periods of dryness in which interstitial gypsum lenses developed, the dried surface of which was grass-colonized, as attested by biomarker analysis.
Alternation of episodes of lagoonal and alluvial fan progradation were also observed in the Pleistocene record of the nearby Elche and Pego basins (Fig. 1; cf. Blázquez, 2005; Blázquez and Usera, 2010; Torres et al., 2013).
Our analysis of pollen content revealed that nuanced Mediterranean biomes
were ever-present, showing a small degree of decoupling with sedimentary
environments.
MIS5e is well represented by lagoonal sediments with ostracods,
foraminifera and brackish water pelecipoda (subunits IV c–e). According to
the pollen record, climate conditions changed from warm-dry to warm and more
humid, ending with more temperate conditions. MIS5d can be correlated with the sedimentary subunit IV-f, marking some
progradation of the alluvial systems, and temperate and humid conditions. MIS5c correlates with subunit IV-g in which lagoonal conditions prevailed.
According to the pollen record, warm and dry conditions prevailed. MIS5b corresponds to subunit IV-h, which marks a new alluvial progradation
with azoic sediments, although the pollen record indicated warm and dry
climatic conditions. MIS5a (subunits IV-i and IV-j) began with the re-establishment of lagoonal
conditions (ostracods, brackish water pelecipoda, Helicidae) under warm and
dry conditions, although the end of this period was marked by alluvial fan
progradation.
The paleogeographical reconstruction suggests that the present-day Antas
river channel incised an ancient lagoon at the end of Upper Pleistocene
after a sudden shift southwards.
Funding was obtained through the projects “Paleoclimatological revision of climate evolution in Western Mediterranean region” (European Union, CE-FI2W-CT91-0075) and “Paleohidrogeological Data Analysis and Model Testing” (European Union, FIKW-CT-2001-00129). The Biomolecular Stratigraphy Laboratory has been partially funded by ENRESA.
Amino acid racemization ratios measured in the ostracod shells from the different horizons of Alfaix fluvial terraces and SRA borehole.
Lithology observed in thin sections of resin-impregnated
samples previously water-sieved (63
Lithology, fossil content and paleoenvironmental interpretation of Units and Sub-Units identified in SRA borehole core (Au F: Autochthonous foraminifers; Al. F.: Allochthonous foraminifers).
Note: Au F: Authochtonous foraminifers; Al. F.: Allochthosnous foraminifers.
Information provided by the
Geographical and Geological setting with the position of the localities. Other localities cited in the paper are also shown (1-Pego Basin; 2-Elche Basin; 3-Fuentillejo).
Stratigraphy and chronology of SRA core with the different sedimentological, micropaleontological and palinological units defined together with the palaeoenvieronmental and palaeoclimatological interpretation.
Profiles of the
Pollen diagram of SRA core.
Synthetic pollen diagram of SRA core.
Principal component analysis of the pollen content in SRA core.