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The La Janda wetland record allows to expand the knowledge of the evolution of a restricted estuary since the Last Glacial Maximum. Multiproxy analysis of the sediments (facies, geochemistry, pollen, fossils) reveals that this system exhibits a classic incised valley sequence but differences with the adjacent estuaries can be established. The La Janda sedimentary infill can be split in four main sequences: (1) the Falling Stage Systems Tract (>20.6 ka BP) and (2) the Lowstand Systems Tract (16.7–20.6 ka BP) deposits record fluvial sedimentation in a narrow and incised valley, here seminally identified in the Gulf of Cádiz estuarine system; and (3) the Transgressive Systems Tract (7–16.7 ka BP), ending with the Holocene marine flooding surface at 7 ka BP, is composed of estuarine and marine basin deposits infilling a still steep and narrow topography coupled with the fast retreat of the river mouths. The (4) Highstand Systems Tract (0–7 ka BP) is composed of estuarine basin deposits with fluvial and tidal currents deposits in a wide a gentle sloped estuarine valley and it records the transformation of the basin into a terrestrial one. Comparison to other areas in the Gulf of Cádiz allows to correlate the different estuaries and to distinguish between open and restricted ones by the development of spit systems during the Highstand Systems Tract. But further work is needed to clarify the stratigraphy of the present eustatic cycle in the Gulf of Cádiz as the scarcity of data does not allow to determine the evolution of its estuaries during the last fall and rise of sea level. Such knowledge is crucial to disentangle the role of climate and tectonics in the future evolution of our coasts and design measures to adapt to sea level rise.

s & presentations / EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022 EGU General Assembly 2022, EGU 2022, Vienna, Austria, 23 May 2022 - 27 May 2022; Göttingen : Copernicus Gesellschaft mbH EGU22-9189 (2022). doi:10.5194/egusphere-egu22-9189, Published by Copernicus Gesellschaft mbH, Göttingen

20 p. - Supplementary material related to this article can be found, in the online version, at doi: https://doi.org/10.1016/j.ejrh.2021.100781., [EN] Study region Old Las Salinas spring in Medina del Campo, Duero river basin, central Spain. Study focus Medina del Campo groundwater body (MCGWB) is a multilayer semiconfined aquifer subject to intensive pumping since the 1970’s, where the current existence of spas where there used to be traditional baths could confirm the existence of deep groundwater flow paths. The old spring of Las Salinas (OSLS) is a saline anomaly in an aquifer with predominance of CaCO3H waters whose occurrence has not yet been formally explained. Long-term geological, geophysical, hydrogeological and hydrochemical records were integrated and complemented with field work to clarify its existence. New hydrological insights for the region Outcomes led to the conclusion that the hydrochemistry of the Olmedo and Palacio de las Salinas salt baths is associated with the existence of a major threshold in the impervious basement of the aquifer, which intercepted deep regional groundwater flow and caused upwelling to the surface under unperturbed conditions. These results allow for the development of a conceptual flow model at the regional scale that explains the changes in natural water chemistry that have been identified in recent decades., This research has received funding from the European Union H2020 Programme under Grant Agreement No. 730497 for the research project NAIAD-NAture Insurance value: Assessment and Demonstration.

Facies and geochemical analysis applied to marsh deposits are useful proxies for the reconstruction of aridity for the last millennia. The comparison of facies and geochemical records among cores from the Almenara and Benicasim marshes allows to identify changes in water level (Si/Al, Al, Ca) and salinity of the feeding waters (Mg/Al, Na/Al, S/Al). These changes, in turn, represent fluctuations in the position of the saline-fresh groundwater boundary, which can be related to variations in sea level and rainfall. For the last 4000 years, three events recording higher salinity conditions (ca. 3.4 ka BP, ca. 3 ka BP and ca. 1.8 ka BP) are noticeable in the record. Comparison to other studies around the Western Mediterranean basin allows us to correlate these events to arid episodes and to identify their forcing mechanisms. These aridity events are correlative to small falls in solar activity and Surface Sea Temperature (SST) during positive North Atlantic Oscillation (NAO) periods. Despite the small magnitude of these changes, the sensitivity of the system amplified the result providing a conspicuous signal.

In AD 1755 a strong earthquake-generated tsunami destroyed large parts of the southwest Iberian coastline. Data for the study of the sedimentological characteristics and palaeo-ecological effects of the backwash of this well-known AD 1755 Lisbon tsunami and possible preceding events on the continental shelf was obtained during RV METEOR cruise M152 in November 2018, since the hydrodynamics of tsunami backwash currents are as yet poorly understood. Furthermore, the suitability of the shelf as a reliable sedimentary archive for tsunami deposits was investigated.Along the Algarve coast, prominent AD 1755 Lisbon tsunami deposits have been detected onshore for quite some time. Cruise M152 conducted a geophysical survey on the corresponding shelf area to obtain bathymetry and sub-bottom profiles for the recognition of depositional basins. Subsequently, 19 sediment cores were retrieved from the most suitable depositional basins by vibracoring at water depths from 65 to 114 m. The cores were analysed in a multiproxy approach (granulometry, magnetic susceptibility, P-wave velocities, organic and inorganic geochemistry, micropalaeontology). Deposits of the AD 1755 Lisbon tsunami were identified in most of the cores as a thin layer at ca. 20 cm depth.More surprisingly, a second event deposit dating to ca. 3700 years cal. BP was detected at core depths of 122 to 155 cm. It is even traceable in the sub-bottom profiles and consists of a distinctive ca. 30 cm thick well sorted medium-sized siliciclastic sand. Due to the thickness of the deposit an in-depth study of its characteristics was possible. It displays an erosive basal contact followed by a thin matrix-poor shell hash layer, a reversely graded fine sand layer and ultimately a massive, quite homogeneous medium sand resembling the Ta division of the Bouma sequence or the S1, S2 and S3 divisions of the Lowe sequence. The deposit is distinguishable from the silt to silty sand-dominated background sedimentation not only due to the textural and compositional features, but also due to contrasting geophysical and geochemical properties. Terrestrial provenance for (at least parts of) the sediment is revealed by biomarker analysis. Based on these characteristics, the deposit is interpreted as the result of a high density hyperpycnal flow from the coast towards the offshore caused by tsunami backwash. This event layer may be correlated to onshore observations of tsunami deposits along the southwest coast of Spain but has never been identified in Portugal where the onshore record of tsunami deposits only covers the last three millennia.The results of this multiproxy analysis strongly suggest the shallow offshore area below storm wave base to host reliable sedimentary archives for tsunami backwash deposits, which allow the discovery of as yet unknown events. Palaeotsunami research can benefit from the investigation of offshore archives, especially where onshore records are incomplete or sparse.

Research on offshore tsunami deposits is scarce and their depositional processes and preservation potential are virtually unexplored. Therefore, the RV Meteor cruise M152 mapped and sampled one coast-parallel and two coast-perpendicular transects at water depths from 65 to 114 m off the Algarve coast (Portugal). This coast was strongly affected by the well-known Lisbon earthquake and tsunami of November 1st, 1755 AD. Numerous onshore locations have been well documented and studied with historic damage reports and modern scientific investigations of the onshore tsunami deposits. However, very scarce information about the backwash, the water masses flowing back into the sea, exists and their imprint on the shelf is unexplored.In order to fill this gap, a total of 19 vibracores were recovered during the RV Meteor cruise M152. For tracing the sedimentary imprint of the AD 1755 tsunami and potential predecessors, a multi-proxy analysis was carried out (sedimentology, micropaleontology, inorganic and organic geochemistry, radiocarbon and OSL dating). Within the offshore Holocene stratigraphic record, at least two event layers of likely tsunami backwash origin were identified based on their significantly different properties compared to the background shelf sediments. The uppermost tsunami layer (at a depth of 16-25 cm in most cores) displays an erosional contact at the base with heterogeneous compositional changes; its bounding radiocarbon ages allow a correlation with the AD 1755 Lisbon tsunami. Organic-geochemical markers, such as n-alkanes, polycyclic aromatic hydrocarbons, steroids and fatty acids, show an increased input of terrestrial matter in this offshore AD 1755 event layer.A surprising discovery was another distinct high-energy deposit, i.e. a potential predecessor to the AD 1755 Lisbon tsunami, at a core depth of about 122-155 cm, which was 14C-dated to approx. 3700 yrs cal BP. Due to its erosional base and coarse-grained composition (well-sorted medium sand), as well as the increased terrestrial influence (displayed by biomarkers), it can be assumed that this deposit originates from the backwash of a paleo-tsunami.This multi-proxy approach with sedimentological, micropaleontological, inorganic and organic-geochemical criteria, enabled us to (1) identify of backwash tsunami deposits; (2) establish a recurrence interval; and (3) estimate the hazard potential for the related coastal areas. Results of the M152 cruise demonstrate for the first time that the depositional basins on the Algarve shelf have the potential to reliably archive Holocene tsunami backwash deposits. The low-energy environment of the outer Algarve shelf sets prime conditions for the preservation of tsunami backwash deposits. Thus, these geoarchives offer the possibility to study the mechanisms and hydrodynamics of backwash currents, and to investigate tsunami strata that are not preserved elsewhere.

The southwest of the Iberian peninsula is, due to its border position between Africa and Europe, a key territory of major geoarchaeological interest, as well as a reservoir of biodiversity and a wildlife refuge area during the Holocene. Bioclimatic conditions have been significantly unstable during this period in the Western Mediterranean. Therefore, further studies are still required to understand how abrupt climate changes such as the 8.2 and 4.2 ka cal BP events impacted societies and environment. In November 2018 the RV Meteor cruise M-152 retrieved 19 vibracores and 4 gravity cores along the Algarve coast after mapping the bathymetry. One of these cores, GeoB23519-01, was taken 65 m below present sea level and recovered 365 cm of sediment. Four potential event layers were identified over the last 11 ka cal BP and, at least two of them, are related to tsunami deposits (ca. 4370 cal BP and AD 1755). This sedimentary archive was analysed in a multi-proxy approach, including palynological and micropalaeontological analyses, which allow characterizing palaeoenvironmental changes along the core. However, considering the characteristics of these deposits, we raise questions about how complex this palynological record is and how it mirrors some short-term events, climate dynamics, and cultural disruptions.

Wetlands are environments whose water balance is highly sensitive to climate change and human action. This sensitivity has allowed us to explore the relationships between surface water and groundwater in the long term as their sediments record all these changes and go beyond the instrumental/observational period. The Lagunas Reales, in central Spain, is a semi-arid inland wetland endangered by both climate and human activity. The reconstruction of the hydroclimate and water levels from sedimentary facies, as well as the changes in the position of the surface water and groundwater via the record of their geochemical fingerprint in the sediments, has allowed us to establish a conceptual model for the response of the hydrological system (surface water and groundwater) to climate. Arid periods are characterized by low levels of the deeper saline groundwater and by a greater influence of the surface freshwater. A positive water balance during wet periods allows the discharge of the deeper saline groundwater into the wetland, causing an increase in salinity. These results contrast with the classical model where salinity increases were related to greater evaporation rates and this opens up a new way of understanding the evolution of the hydrology of wetlands and their resilience to natural and anthropogenic changes.

The study of flooding can be complex as it involves dynamic systems (rivers) characterized by high variability in time and space. To minimize the effects of these handicaps, we merge several records from different locations across the hydrographic basin of the Upper Guadiana River (central Spain) and use multiple proxies. The comparison of three nearby cores by means of the facies, stratigraphic correlation and geochemical indexes allows us to differentiate local environmental changes related to the natural behaviour of the system (autocyclic) from those driven by external forcings (allocyclic). The facies and facies sequence analyses allow long-term paleohydrological trends to be reconstructed and parameters that are used to identify flooding events to be determined. Si (proxy for siliciclastic supply) and Ca/S (proxy for water budget/level) show trends that can be related to facies sequences and long-term variations. Si/Al is used as a sorting proxy (transport efficiency). To analyse the relative changes in sediment discharge and transport efficiency, these proxies are compared with water budget level, represented by (Si/Al)/(Ca/S) (sorting vs. water level) and Si/(Ca/S) (siliciclastic discharge vs. water discharge). We were able to define local, major and minor regional flood events/periods and events by relating sequence boundaries to the occurrence of environmental conditions related to high energy events (relative/absolute sorting, water level, sediment discharge) across multiple cores. Comparison to other studies around the western Mediterranean basin allows us to identify common periods of flooding at 9000–8400 cal. BP, 7700–7100 cal. BP, 6400–6200 cal. BP, 4900–3700 cal. BP, 3500–3300 cal. BP, ca. 2600 cal. BP, ca. 2000 cal. BP, ca. 1500 cal. BP and 1000–300 cal. BP. For the long-term evolution, it seems that changes in insolation during the Holocene could have played a role in controlling the hydrology. However, determining the drivers of higher-frequency variation is more challenging due to uncertainties in the chronologies and local differences. Nevertheless, some degree of correlation among these flooding periods and higher frequency changes in irradiance, temperature and NAO is observed., Departamento de Geodinámica, Estratigrafía y Paleontología, Universidad Complutense de Madrid, España, Instituto Geológico y Minero de España, España

Floods are one of the gravest natural hazards for societies, worsened by population growth, unchecked development, and climate change. From a Global Change perspective, past extreme events merit particular interest because they can be linked to wider climate and environmental changes, introduce perturbations. During the last decade, knowledge of long-term flood frequency and magnitude has been improved by extracting data from different types of archive. But, despite advances in dating methods, proxies and statistical techniques and efforts to identify atmospheric drivers, some fundamental questions remain unresolved. The Special Issue entitled “Pluridisciplinary analysis and multi-archive reconstruction of paleofloods” in the journal Global and Planetary Change addresses these uncertainties and complexities by assembling a selection of studies, which were first presented at the Past Climate Changes (PAGES) Open Scientific Meeting held at Zaragoza in 2017. In this introductory paper, the guest editors outline the 17 research contributions and meta-data from the 17 paleoflood studies were systematically analyzed in terms of i) geographical distribution; ii) methodologies applied; iii) types of archives; iii) numbers of flood series compiled and iv) spatial and temporal resolution of paleoflood data. The data indicate that paleoflood studies focused on fluvial depositional environments show a higher rate of integration with other types of paleoflood archive (mean of 4.5 types of archive) than studies focused on documentary sources (mean of 3.5) and lake sediments (mean of 2.4). We suggest that this strategy of archive integration has been adapted to effectively compensate for the higher uncertainties of fluvial deposition in floodplains. Statistical processing of the meta-data shows quantitative associations between specific types of flood archive and offers a solid platform for designing the optimal approach for multi-archive paleoflood research. A qualitative review and visual comparison of the 17 paleoflood series shows some consistent trends and breaks but also notable differences within and between regions. While a trend of increased flooding since 4-5 ka BP is evident, the lack of synchronicity between breaks and the coeval increases and decreases in fluvial activity is manifest. The majority of studies in the Special Issue do denote the 19 th century – including the youngest cool climate pulses during the Little Ice Age – as a particularly flood-rich period. It is more difficult to assess the 20 th century because of social changes, population growth and extensive river modification. Despite the mentioned uncertainties, 10 of 14 papers do not record the 20 th century as an exceptional flood period. Assessing the effects of human impact on paleoflood calendars and disentangling anthropogenic from natural drivers are major challenges in integrated paleoflood analysis. It is concluded that the interpretation of flood series is complex as landscapes and flood drivers are heterogeneous and systems show different sensitivities to flood control and drivers. Thus, the study of past floods, from historical and natural archives, is challenging but also offers unparalleled opportunities to document low-frequency, large-magnitude flood events, which occurred under a broad range of climate and/or environmental scenarios, and, probably, the only way to reconstruct robust paleoflood series.

In this paper we analyse and compare the efficiency of electrical resistivity imaging (ERI) and ground-penetrating radar (GPR) as tools for stratigraphic and sedimentological studies. To this end, we carried out borehole drilling and geophysical survey campaigns in two locations in Las Tablas de Daimiel area (Ciudad Real, Spain). In this region, the Quaternary record is build up by siliciclastic deposits (gravel, sand and silt) of fluvial origin and organic matter-rich sediments (peat, clay and silty clay rich in organic matter) and carbonates (biogenic deposits mainly made up of Characeae) deposited in fluvial wetland environments that rest on Ordovician quartzites and Pliocene karstified carbonates. Electrical resistivity imaging (ERI) supported by surface and subsurface (boreholes) lithological information allow to identify the geometry of the basement-Quaternary boundary in two areas. The morphology of this boundary is controlled by fractures and the karstification of the top of the Pliocene limestones. Thirteen GPR profiles (100 and 250 MHz antenna) provide information about the morphology and internal structure of the sedimentary units, down to 4 m below the surface. The observed features include: onlap of the sediments on the edge of the basin, fossilization of small paleo-reliefs by lacustrine deposits and channel fills in the Holocene deposits, and the sinking-collapse structures in the Neogene substratum., Departamento de Geología, Universidad de Jaén, España, Departamento de Ingeniería Mecánica y Minería, Universidad de Jaén, España, Instituto Geológico y Minero de España, España, Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Centro de Estudios y Experimentación de Obras Públicas, España

Knowledge about the relative impact of climate and socio-economic factors on agriculture is still not well known as they change in space and time. Social researchers stress the role of endogenous (societal, economical, etc.) factors whilst physical/natural scientists focus on the role of climate on land use and land cover change, but the latter do not usually focus on human dynamics. Through the analysis of proxies of land cover, sediment yield (erosion) and salinity changes from sediments in a fluvial wetland in central Spain and documentary evidence collected from the 16th century onwards, it becomes clear that climate impact on farming has changed during this period. Thus, until ca. 1725 CE, agriculture production in central-southern Spain followed the cycles and trends of rainfall at the annual, multiannual and decennial time scales. From that time onwards, production began to show discrepancies with climate, with high production cycles associated with dry periods being common and a sustained productivity that was independent of climate trends and it must be related to socio-economic changes. This change from climate-driven to human-driven agriculture can be seen in other areas of the Iberian Peninsula but at different times that vary from the first half of the 17th century until the first half of the 18th century. These different times can be attributed to diachronous changes in the Little Ice Age phases and local and regional differences in economic factors (such as proximity to commercial routes, development of markets) and their evolution, as supported by the different information sources., Departamento de Geodinámica, Estratigrafía y Paleontología, Universidad Complutense de Madrid, España, Museo Comarcal de Daimiel, España, Instituto Geológico y Minero de España, España, Departamento de Geología, Geografía y Medio Ambiente, Universidad de Alcalá de Henares, España, Centro de Estudios y Experimentación de Obras Públicas, España

This Special Issue, which comprises 18 peer-reviewed papers, is the outcome of the Floods Working Group (FWG) session entitled "Multidisciplinary reconstruction of paleofloods" held at the PAGES OSM Conference (Past Climate Changes - Open Scientific Meeting) from 9-13 May 2017 in Zaragoza, Spain. Sixteen oral contributions and eighteen posters from most continents were presented and lively discussion ensued.

Las Tablas de Daimiel National Park is one of Spain's most representative groundwater‐ dependent ecosystems. Under natural conditions, water inflows combined brackish surface water from River Gigüela with freshwater inputs from River Guadiana and the underlying aquifer. Since the mid‐1970s, aquifer overexploitation caused the desiccation of the wetlands and neighbouring springs. The National Park remained in precarious hydrological conditions for three decades, with the only exception of rapid floods due to extreme rainfall events and sporadic water transfers from other basins. In the late 2000s, a decrease in groundwater abstraction and an extraordinarily wet period reversed the trend. The aquifer experienced an unexpected recovery of groundwater levels (over 20 m in some areas), thus restoring groundwater discharge to springs and wetlands. The complex historical evolution of the water balance in this site has resulted in substantial changes in surface and groundwater quality. This becomes evident when comparing the pre‐1980 groundwater quality and the hydrochemical status in the wetland in two different periods, under “dry” and “wet” conditions. Although the system is close to full recovery from the groundwater‐level viewpoint, bouncing back in the major hydrochemical constituents has not yet been obtained. These still appear to evolve in response to the previous overexploitation state. Moreover, in some sectors, there are groundwater‐dependent ecosystems that remain different to those found in preoverexploitation times. The experience of Las Tablas de Damiel provides an observatory of long‐term changes in wetland water quality, demonstrating that the effects of aquifer overexploitation on aquatic ecosystems are more than a mere alteration of the water balance and that groundwater quality is the key to aquifer and aquatic ecosystem sustainability., Centro de Estudios y Experimentación de Obras Públicas, España, Instituto Geológico y Minero de España, España, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid, España, UNESCO/UNITWIN Chair “Appropriate Technologies for Human Development", Universidad Complutense de Madrid, España

We use a combined allostratigraphic and morpholithostratigraphic approach to establish a relative stratigraphy of macroscale sediment-landform units in the Mediterranean Palancia River watershed (986-km2, NE Spain). Four alloformations signifying important changes in (sub)regional scale geomorphic valley-floor evolution were identified based on data from 1120 field sites and age determinations, and from analyzing high resolution geodata. The formation of the widespread and thick Pleistocene alloformation can be attributed to climatically-induced excessive sediment supply and flood activities during Pleistocene cold intervals — rather than representing time-lagging response to Plio/Pleistocene neotectonic uplift. Triggered by the turn to Holocene climatic conditions, three successively inset alloformations illustrate how stream grading and floodplain narrowing continuously have progressed over the Holocene. The overall degradational valley-floor evolution in the Holocene is interpreted as a response to the antecedent, overly valley-floor aggradation. Allostratigraphic and morphostratigraphic data suggest that the abandonment of the two earlier Holocene alloformations geomorphologically represents a pulsed turn toward intensified entrenchment rather than pulsed sedimentation. The most important benefit of amalgamating allostratigraphic and (morpho)lithostratigraphic concepts is that allostratigraphic ordering provides a formally conclusive approach to scale up (morpho)lithostratigraphic information from the reach scale to much larger scales of geographical extent. Consequently, applying allostratigraphic principles opens a perspective to moving forward toward analyzing the relationships between climate, neotectonics, sea level change, human impact, and fluvial response in coupled hinterland-coastal systems that require to evaluate sedimentary information at larger spatial scales.

Here, we present a terrestrial multi-proxy record of Late Quaternary environmental changes in the southern Iberian Peninsula covering approximately 30 ka. This sedimentary record originates from a saline playa lake (Laguna de Fuente de Piedra) hosted within a complex geological setting dominated by Triassic claystones and evaporites, Jurassic carbonates and Miocene deposits leading to a complex hydrogeological setting. Dissolution of evaporites in the catchment and intense evaporation are responsible for saline waters fluctuating in the basin. Thus, salinity as palaeohydrological proxy, requires a decoupling of internal and external hydrogeochemical processes. The greatest accumulation of evaporites in the LFP late Pleistocene–Holocene record coincides with a more humid or, at least, less evaporative, period. Based on multi-proxy data we describe five lacustrine lithofacies (2–5), and fluvial deposits (1) from sediment cores. The proposed conceptual lake margin model contains three main lake water stages repeated within the sedimentary succession and building up the characteristic lithofacies. Lake water stages refer to a flooding stage (influx > outflux), high water stage (influx = outflux), and low water stage (influx < outflux). The lithostratigraphy reveals a palaeohydrological record suggesting climate changes and associated lake level fluctuations. Lake level oscillations of different amplitudes have been identified. Low amplitude changes have been revealed for the periods from 28 ka cal BP to 17.5 ka cal BP and from 8.2 ka cal BP to present, whereas in between (17.5 ka cal BP to 8.2 ka cal BP) the Late Pleistocene/Holocene transition shows high amplitude lake level changes. The latter coincides with an increased influence of saline subsurface waters, due to groundwater level rising (sulfate signature). In contrast, the Holocene, records the low amplitude oscillations and a drop of the groundwater levels, which creates a less saline or fresher footprint in the sediments (carbonate signature). Thus, the periods of low amplitude lake level oscillations, low inputs of clastics and low groundwater levels (drier) coincide with periods of minimal seasonal insolation difference. In contrast, the period of higher amplitude lake level oscillations, higher input of clastics and higher groundwater table (wetter) is correlative to periods of maximum difference between summer and winter insolation., This study is a contribution to the Collaborative Research Centre 806“OurWay toEurope”. The project CGL2011-30302-C02-01,financed by the Spanish Ministry of Economy and Competitiveness, has provided technical and scientific support to this research.

Human settlements around the fluvial wetland of Las Tablas de Daimiel (central Spain) have been related to the water availability in this area for nearly 5500 years; however the relationship of the hydrology of the wetland to climate change remains uncertain. Whilst archaeological and pollen data provide contradictory arguments, statistical empirical mode decomposition of geochemical data from core S-1 reveals arid periods ca. 1.8 cal. ka BP, ca. 3.3 cal. ka BP and ca. 5.5 cal. ka BP between which periods both Bronze Age and Iberian-Roman settlements developed. These periods can be identified in other records of the Iberian Peninsula and around the western Mediterranean. Comparison of these records points to a complex spatial pattern that evolved in time and, despite a number of forcings (volcanism, solar activity, atmosphere-ocean interactions) being invoked to explain such periods, there is no clear mechanism to explain their spatial pattern and the changes that have taken place since 2.5 ka BP., Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Instituto Geológico y Minero de España, España, Museo Comarcal de Daimiel, España, Centro de Estudios y Experimentación de Obras Públicas, España

Knowledge of the evolution of Spanish fluvial networks has improved during recent years as more river systems have been studied and more geochronological data has become available. However, the chronological framework is a major issue as the range of applications is limited by methodological constraints and spatial coverage is sparse. Integration of ‘absolute’ dating methods with biostratigraphy and palaeomagnetism permits the recent evolution of these river systems to be reviewed. The timing of incision from the Late Neogene to the present varies between the major Iberian fluvial systems, depending on the substrata and tectonic settings. Early Pleistocene and older fluvial sequences in the core areas of the Iberian Peninsula provide a more extensive record of fluvial evolution and are better preserved than the terrace flights in the coastal lowlands. Middle Pleistocene sequences are well developed in most of the major river systems in Iberia, particularly those of the Tajo, Guadalquivir and Aguas River, and frequently represent the principal climatic cycles of that period, although tectonic and sea-level effects can also be seen. For Late Pleistocene to Holocene times, the scheme becomes more complex. Our review suggests that each river system has responded differently to local and regional climate control, glacial and periglacial processes in headwaters in high mountain areas, glacio-eustatic sea-level changes and local and regional tectonic patterns.

Weathering processes are responsible for slight surface mineralogical differences allowing the distinction between lithologically similar geological units using Thematic Mapper (TM) data. Two different stages throughout time of overlying iron alteration are notoriously distinctive on the imagery and laboratory spectra. Their diverse spectral behaviour follows the dominant iron hydroxide with kaolinite and carbonate crusts on the Pliocene Ochre Alteration typical of a humid warm climate, compared with the dominant nonhydratated iron oxides with smectite on the Miocene Red Alteration developed under a mediterranean dry climate. Iron materials with carbonate hinder appearance of the typical iron absorption features in the visible wavebands. Therefore, the iron weathering alteration coatings will be obscured on the imagery when it is developed on carbonate sediments or detritic sediments with carbonate cement or matrix. The presence of carbonate within the sediment as cement or alteration product decreases the overall reflectance of laboratory nonconsolidated rocks and the clay size fraction from rocks, apart from smoothing the 2200 nm absorption typical of OH-bearing minerals. The presence of carbonate cement and carbonate crusts favours the differentiation of some units. Digital mapping through image processing of different series of digital data leads to a sequential masking of classes to produce a final map. The sequence of masking produces different maps which can be used as a tool to model aspects of the sedimentary basin and geological processes throughout time.

Rogation (ceremonies to ask God for rain: pro-pluvia, or to stop raining: pro-serenitate) analysis is an effective method to derive information about climate extremes from documentary data. Weighted annual sum by levels has been a widespread technique to analyze such data but this analysis is liable to be biased to spring values as these ceremonies are strongly related to farming activities. The analysis of the length of pro-pluvia periods (the time span during which rogations are carried out in relation to a drought event) and the combination of annual and seasonal information offers a more objective criterion for the analysis of the drought periods and an increase in the resolution of the study. Analysis by the pro-pluvia periods method of the rogation series from the Toledo (central Spain) Cathedral Chapter allows a good characterization of the droughts during the 1506–1900 period. Two drought maxima appear during the 1600–1675 and 1711–1775 periods, characterized by rogations during almost all the year, with a middle stage (1676–1710) when droughts were less frequent and their length shortened. Sea level pressure patterns for the instrumental and documentary periods show that droughts were mostly related to a north-eastern position of the Azores High that displaced the Atlantic low pressure systems towards a northern position. There is a weak relation with the North Atlantic Oscillation but this fact is related to the local character of the series that increases the weight of the local factors. Comparison of rainfall/drought records around Spain and the Western Mediterranean reveals the heterogeneity of their distribution in time and space as well as stresses the need of more and longer reconstructions. Better knowledge of drought variability would help to improve regional models of climate extremes and the understanding of the atmospheric patterns related to their development., Dirección de Geología y Geofísica, Instituto Geológico y Minero de España, España, Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Departament d'Història Moderna, Universitat de Barcelona, España

River terraces are well established as an important source of Lower and Middle Palaeolithic artefacts in Europe, large collections having been assembled there during the years of manual gravel extraction. Now that many terrace sequences can be reliably dated and correlated with the oceanic record, potentially useful patterns can be recognized in the distribution of artefacts. The earliest appearance of artefacts in terrace staircases, marking the arrival of the first tool-making hominins in the region in question, is the first of several archaeological markers within fluvial sequences. The Lower to Middle Palaeolithic transition, with the appearance of Levallois, is another. Others may be more regional in significance: the occurrences of Clactonian (Mode 1) industry, twisted ovate handaxes and bout coupe´ handaxes, for example. IGCP Project no. 449 instigated the compilation of fluvial records from all over the ‘old world’. Comparison between British and Central European sequences confirms the established view that there is a demarcation between handaxe making in the west and flake/core industries in the east. Other centres of activity reported here have been in the Middle East (Syria), South Africa and India. Data from such areas will be key in deciphering the story of the earlier ‘out-of-Africa’ migration, that by pre- Homo sapiens people. There is clear evidence for diachroneity between the first appearances of different industries, in keeping with the well-established idea of northward migration.

Vertebrate and invertebrate faunal biostratigraphy is a well-tested method for establishing relative chronologies for fluviatile sequences that has proved useful in many parts of the world. The robust bones and teeth of large mammals are commonly found in fluviatile deposits, whereas small vertebrates can be readily recovered through systematic sieving of calcareous sediments, as can molluscs, the other major faunal group that has been used for biostratigraphical analysis of fluvial sequences. Because of their rapid and quantifiable rates of evolution, extinction, body mass change and dispersal during the Late Cenozoic, mammals are especially useful for ordering the fragmentary terrestrial sequence of interglacials and glacials, and proposing correlation with the global marine climatostratigraphic record. Other groups (e.g. reptiles and amphibians, ostracods) are as yet only in the initial stages of development as a dating tool, whereas some (e.g. fish, birds) still require substantial development in order to fully explore their utility. As part of IGCP 449, vertebrate and molluscan assemblages have made important contributions to datasets from a number of areas, notably northern France, central Germany, the Czech Republic and the Ukraine. Further south, mammalian assemblages have proved useful in separating discrete periods of climatic change in Iberia and Syria. At greater distances from the core area of fluvial biostratigraphical archives, significant contributions have come from South America (Uruguay River), South Africa (Vaal) and Australia (Riverine Plain and Lake Eyre drainage basin).

The use of a high resolution pollen record in combination with geochemical data from sediments composed mainly of layers of charophytes alternating with layers of vegetal remains plus some detrital beds permits the reconstruction of the environmental evolution of the last 3000 years in an inland wetland of the Mediterranean domain, thus introducing a new climatic dataset for the Late Holocene. Hydrological fluctuations, reflected in the relationship between emerged and aquatic vegetation and inorganic and organic C and N changes, can be related to aridity or humid phases, while relations among arboreal taxa (Quercus and Pinus) and Artemisia are used as temperature indicators. Five climatic periods have been identified: a Subatlantic Cold Period (A.D. 1400) indicated by a cooling and drying trend. Despite the lack of any direct evidence of human action, there are some episodes related to deforestation during the Reconquista (Middle Ages) that mask the real climatic signal., Departamento de Geología, Universidad de Alcalá de Henares, España, Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Dirección de Geología y Geofísica, Instituto Geológico y Minero de España, España, Dirección de Recursos Minerales y Geoambiente, Instituto Geológico y Minero de España, España

Las Tablas de Daimiel National Park has experienced many hydrological and ecological modifications through out its history, both of natural as well as anthropogenic origin, which have affected its carbon storage capacity and carbon fluxes. The study of those variations has been carried out by the analysis of its sedimentary record (geochemistry and pollen) and historical data. The natural changes have a wider variation range than the anthropogenic ones, showrepetitive patterns and the system reacts readjusting the equilibrium among its components. Anthropogenic effects depend on the direct or indirect impact on the wetlands of change and its intensity. In addition, the anthropogenic impacts have the capacity of breaking the natural balance of the ecosystem and the internal interactions., Dirección de Geología y Geofísica, Instituto Geológico y Minero de España, España, Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Earth Surface Processes, United States Geological Survey, Estados Unidos, Dirección de Recursos Minerales, Riesgos Geológicos y Geoambiente, Instituto Geológico y Minero de España, España, Departamento de Geología, Universidad de Alcalá de Henares, España

IGCP 449 (2000–2004), seeking to correlate fluvial records globally, has compiled a dataset of archaeological records from Pleistocene fluvial sequences. Many terrace sequences can now be reliably dated and correlated with marine oxygen isotope stages (MIS), allowing potentially useful patterns in artefact distribution to be recognised. This review, based on evidence from northwest European and German sequences (Thames, Somme, Ilm, Neckar and Wipper), makes wider comparisons with rivers further east, particularly the Vltava, and with southern Europe, especially Iberia. The northwest and southern areas have early assemblages dominated by handaxes, in contrast with flake-core industries in Germany and further east. Fluvial sequences can provide frameworks for correlation, based on markers within the Palaeolithic record. In northwest Europe the first appearance of artefacts in terrace staircases, the earliest such marker, dates from the mid–late Cromerian Complex. Flake-core industries may have significantly preceded handaxe industries in southern Europe. An important technological innovation—Levallois technique—occurs at the Lower-Middle Palaeolithic boundary, correlated with MIS 9–8. Humans deserted northern Europe during MIS 6, apparently returning to central Germany and northern France (Somme valley) by MIS 5e but not reaching southern England until the appearance of Mousterian culture during MIS 4–3.

Since the publication of the paper of , loss on ignition (LOI) has been widely used as a method to estimate the amount of organic matter and carbonate mineral content (and indirectly of organic and inorganic carbon) in sediments. The relationships between LOI at 550 °C (LOI550) and organic carbon (OC) content and between LOI at 950 °C (LOI950) and inorganic carbon (IC) content are currently accepted as a standard. However, the comparison of 150 analyses of samples of diverse lithologies, collected from a single core, reveals that these relationships are affected by sediment composition (presence of clays, salts, and the variable content of organic carbon). This results in an incremental error on the estimation of carbon content from LOI values that invalidates the use of LOI values as a quantitative method for estimating carbon content. Conversely, the general trends of LOI550 and LOI950 show a good correlation with carbon content (both organic and inorganic) allowing use of LOI as a qualitative test for carbon content. Similarly, in our case, LOI at 105 °C (LOI105) is a good qualitative proxy for the trends in gypsum content., Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Departamento de Geología, Universidad de Alcalá de Henares, España, Dirección de Geología y Geofísica, Instituto Geológico y Minero de España, España, Dirección de Recursos Minerales y Geoambiente, Instituto Geológico y Minero de España, España, Dirección de Hidrogeología y Aguas Subterráneas, Instituto Geológico y Minero de España, España, Departamento de Geodinámica, Universidad Complutense de Madrid, España

The rise of the Central System due to reactivation of late Hercynian fault systems during the Alpine Orogeny directly affected the strcture and stratigraphic framework of the basins nearby that were being filled al the same time. The sedimentary record is the essential key to understanding the tectonic and palaeo-morphological history, of the Central Range, and vice-versa. Relating the filling of the basins with the definition of the mountain range, pre-arkosic, arkosic and post-arkosic stages have been proposed. However, it is difficult to support the previous idea that the arkosic stage continued throughout the Late Tertiary to finish in Middle Pliocene.: times withe the deposition of the Paramos(limestone). The arkoscs of the Central System arc of Eocene-Oligocce age and the highest alluvial fan deposits may be of Aragonian age. There is only a poor record of the remaining Tertiary and Quaternary sediments. boeause of active river incision during this lime in the hasins, the ranges and elsewhere in the Spanish Meseta.