Nuevos datos cronoestratigráficos de la Fm. Marismas (Bajo Guadalquivir)

La Formación Marismas forma la parte superior del relleno sedimentario del sector SW de la cuenca del Guadalquivir. Los datos previos sobre el sondeo Lebrija, indicaban que la parte más alta de esta formación tenía edades de hasta 9.6 kyr BP y en la parte inferior eran cercanas o fuera del rango del radiocarbono, pero posterior a la reversión Brunhes-Matuyama. En este trabajo se aportan 17 nuevas dataciones realizadas mediante racemización de aminoácidos en valvas de ostrácodos en este mismo sondeo, con el fin de completar la cronología y el modelo de edad de la parte superior e inferior de la Fm Marismas. El resultado indica que el tramo situado por debajo del metro 56, arroja edades que oscilan entre 164685±14110 y 202830±30255, que se correlacionan con los estadios isotópicos marinos MIS 6-7 del Pleistoceno medio, edad sensiblemente más baja a las inferidas para esta formación en otros puntos de la Cuenca del bajo GuadalquivirEste trabajo se ha realizado dentro del proyecto Guadaltyc (Impacto del clima y la tectónica en el registro sedimentario de la Cuenca del Guadalquivir, (CGL2012-30875).Peer Reviewe

Early Pliocene climatic optimum, cooling and early glaciation deduced by terrestrial and marine environmental changes in SW Spain

The Pliocene is a key period in Earth's climate evolution, as it records the transition from warm and stable conditions to the colder and more variable glaciated climate of the Pleistocene. Simultaneously, climate became more seasonal in the Mediterranean area, and Mediterranean-type seasonal precipitation rhythm with summer drought established. These climatic changes presumably had significant impacts on terrestrial environments. However, the response of terrestrial environments to such climate changes is still not fully understood due to the lack of detailed studies dealing with this period of time. In this study, multiproxy analyses of continuous core sampling from La Matilla (SW Spain) shows detailed and continuous record of pollen, sand content and abundance of benthic foraminifer Bolivina spathulata to describe paleoenvironmental and paleoclimate trends during the early Pliocene. This record shows warmest, most humid climate conditions and highest riverine nutrient supply at ~ 4.35 Ma, coinciding with the Pliocene climatic optimum and high global sea level. A climate cooling and aridity trend occurred subsequently and a significant glaciation occurred at ~ 4.1–4.0 Ma, during a period known by very little terrestrial evidence of glaciation. Our multiproxy data thus indicate that terrestrial and marine environments were significantly variable during the early Pliocene and that major glaciation-like cooling occurred before the intensification of northern hemisphere glaciation at the beginning of the Pleistocene (~2.7 Ma). This major climate cooling and aridity maxima between 4.1 and 4.0 Ma is independently validated by a coeval sea-level drop (third order Za2 sequence boundary). This sea level drawdown is supported by enhanced coarse sedimentation and minima in riverine nutrient supply, showing paired vegetation and sea-level changes and thus a strong land-ocean relationship. This study also shows that long-term climatic trends were interrupted by orbital-scale cyclic climatic variability, with eccentricity, obliquity and precession acting as the main triggers controlling climate and environmental change in the area.Peer ReviewedPostprint (author's final draft

Responding to the challenges of Water and Global Warming: Environmental Hydrogeology and Global Change Research Group (HYGLO-Lab)

[EN] The current Global Warming of planet Earth is probably the most important geological phenomenon in the last 20,000 years of its history and for human race. This process is having nowadays notable effects on the climate, ecosystems and natural resources. Possibly the most important renewable geological resource is water. One of the most strategic phases of the water cycle is groundwater. Despite its low visibility, quantitatively (and qualitatively too) it is essential for life on Planet Earth. Foreseeable consequences on groundwater due to climate change and sea level rise will be very significant. Hydrogeology can provide answers to many of the questions that are beginning to be raised in relation to these impacts and their effects. Environmental hydrogeology is a way of understanding the set of disciplines mixed in Hydrogeology as a Science of Nature. The HYGLO-Lab Research Group of the IGME-CSIC National Center attempts, through its lines of research, with a double global and local component, to provide answers to some of these questions.Peer reviewe

Doñana

Desde tiempo inmemorial las tierras que adornan el bajo Guadalquivir han sido surcadas por diferentes culturas y prueba de ello son las abundantes evidencias arqueológicas. Lejos queda ya aquel estuario de aguas salobres gobernado por el mar, surcado por tartessos. Hoy Doñana se engalana de espectaculares flechas litorales, extensos sistemas dunares y una marisma de proporciones inmensas, albergando una de las mayores concentraciones de aves que uno pueda imaginar, Ningún paisaje muestra mejor su dinamismo a lo largo de los tiempos, aunque su reloj discurre muy lentamente para nosotros, ¡pobres mortales! El viento, el mar, el río, de dinámica feroz, han conformado un paisaje vivo, que a lo largo de milenios ha ido dejando marcas de su discurrir en forma de dunas, navazos, vetas, paciles..., que los geólogos intentamos desenmarañar, para contar una historia que subyace en las arenas y fangos de uno de los paisajes más evocadores a los que uno se pueda enfrentar.Facultad de Ciencias Experimentales, Universidad de Huelva, EspañaInstituto Geológico y Minero de España, Españ

Investigating the impact of climate change on groundwater recharge using a high precision meteo lysimeter in a dune belt of the Doñana National Park

Congress on Groundwater and Global Change in the Western Mediterranean (2017. Granada)Although precise weighing lysimeters are mostly installed for agricultural purposes in crop-producing areas, these instruments are also useful in areas of ecological interest where soil and aquifer recharge-discharge processes need to be better understood. In September 2015 a high precision meteo-lysimeter was installed in a coastal dune of the Doñana Natural Reserve to quantify the recharge in dune belts, and to estimate its dependence on regional climate trends. In addition to the lysimeter, also six soil moisture sensors (model CS650) and 2 meteorological stations were installed. The first results show recharge rates of natural precipitation ranging from 19 to 97%, depending on the meteorological conditions and the initial soil moisture. The lysimeter-measured rainfall generally exceeded the measurements of the tipping bucket. Also the contribution of the dew was detected by the lysimeter. A soil water model is currently being set up to simulate recharge, soil water movement, evaporation and percolation, as well as to quantify uncertainty and noise effects.Unidad de Sevilla, Instituto Geológico y Minero de España, EspañaInstituto Andaluz de Investigación y Formación Agraria, Pesquera, Alimentaria y de la Producción Ecológica, EspañaDepartamento de Agronomía, Universidad de Córdoba, EspañaPeer reviewe

Early Pliocene climatic optimum, cooling and early glaciation deduced by terrestrial and marine environmental changes in SW Spain

This article is subject to a Creative Commons Attribution Non-Commercial No Derivatives LicenseThe Pliocene is a key period in Earth's climate evolution, as it records the transition from warm and stable conditions to the colder and more variable glaciated climate of the Pleistocene. Simultaneously, climate became more seasonal in the Mediterranean area, and Mediterranean-type seasonal precipitation rhythm with summer drought established. These climatic changes presumably had significant impacts on terrestrial environments. However, the response of terrestrial environments to such climate changes is still not fully understood due to the lack of detailed studies dealing with this period of time. In this study, multiproxy analyses of continuous core sampling from La Matilla (SW Spain) shows detailed and continuous record of pollen, sand content and abundance of benthic foraminifer Bolivina spathulata to describe paleoenvironmental and paleoclimate trends during the early Pliocene. This record shows warmest, most humid climate conditions and highest riverine nutrient supply at ~ 4.35 Ma, coinciding with the Pliocene climatic optimum and high global sea level. A climate cooling and aridity trend occurred subsequently and a significant glaciation occurred at ~ 4.1–4.0 Ma, during a period known by very little terrestrial evidence of glaciation. Our multiproxy data thus indicate that terrestrial and marine environments were significantly variable during the early Pliocene and that major glaciation-like cooling occurred before the intensification of northern hemisphere glaciation at the beginning of the Pleistocene (~2.7 Ma). This major climate cooling and aridity maxima between 4.1 and 4.0 Ma is independently validated by a coeval sea-level drop (third order Za2 sequence boundary). This sea level drawdown is supported by enhanced coarse sedimentation and minima in riverine nutrient supply, showing paired vegetation and sea-level changes and thus a strong land-ocean relationship. This study also shows that long-term climatic trends were interrupted by orbital-scale cyclic climatic variability, with eccentricity, obliquity and precession acting as the main triggers controlling climate and environmental change in the area. © 2019 Elsevier B.V.This study was supported by the research projects CGL2012-30875 (GUADALTYC), CGL2013-47038-R, CGL-2017-85415-R and CGL2014-59516 (MITE) of the Ministerio de Economía y Competitividad of Spain, project P11-RNM-7332 from the Junta de Andalucía, and the Research Groups RNM-190 of the Junta de Andalucía and GRC Geociències Marines (2017 SGR 315) of the Generalitat de Catalunya.Peer reviewe