Blas Lorenzo Valero-Garcés

Blas Lorenzo Valero-Garcés
Spanish National Research Council | CSIC · Instituto Pirenaico de Ecología

Ph D Geology

About

363
Publications
102,896
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11,081
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Additional affiliations
August 1991 - June 1995
University of Minnesota Twin Cities
Position
  • Fulbright Fellow and Post Doc
September 1986 - August 1991
University of Zaragoza
Position
  • PhD Student

Publications

Publications (363)
Article
Full-text available
Our understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity of well-dated tropical records of glaciation that span several glacial–interglacial intervals. Glacial deposits offer discrete snapshots of glacier extent but cannot provide the continuous records required for detailed interhemispheric comparis...
Conference Paper
Full-text available
Centimeter-thick layers of gypsum (CaSO4·2H2O) were deposited at the bottom of Laguna de Zoñar (Córdoba Province, southern Spain) from ~2120 to ~1900 cal yr BP [1], coinciding with the apogee of the Roman Empire in the Iberian Peninsula. The presence of gypsum deposits in lake sediments is generally interpreted as evidence of dry climatic periods i...
Article
Hypersaline lakes are unique depositional environments that are highly sensitive to climatic changes and anthropogenic pressures. Strong physicochemical gradients and the interplay of physical, chemical and biological depositional processes coupled to variable preservation potential associated with these environments generate highly complex sedimen...
Article
Full-text available
The Mediterranean region is expected to be highly impacted by global warming, although the uncertainty of future scenarios, particularly about precipitation patterns remains quite large. To better predict shifts in its current climate system and to test models, more regional climate records are needed spanning longer than the instrumental period. H...
Article
Study region Two giant pockmarks in Lake Banyoles (NE Spain) have been surveyed over the last 35 years. The giant pockmark ‘B1’ has maintained an ‘eruptive’ mode with permanent groundwater discharge, whereas, the giant pockmark ‘B2’ has displayed alternating quiescent and eruptive phases. Study focus Interannual variability of lake-subsurface grou...
Article
Full-text available
We present the first reconstruction of past flood events variability in the Basque Country and Western Ebro Basin (Northern Spain) integrating instrumental hydrological datasets (last 20 years), documentary archives (last 700 years) and Lake Arreo (655 m a.s.l.) sedimentary paleoflood record (last 1400 years). In this lake, allochthonous coarse and...
Article
Global afforestation/deforestation processes (e.g., Amazon deforestation and Europe afforestation) create new anthropogenic controls on carbon cycling and nutrient supply that have not been fully assessed. Here, we use a watershed-lake dynamics approach to investigate how human-induced land cover changes have altered nutrient transference during th...
Preprint
The Pyrenean Lake Montcortès sediments hold the longest continuous and absolutely varve-dated record of the Mediterranean region, encompassing the last three millennia, from the Late Bronze Age to the present. The reconstruction of vegetation and landscape dynamics during this time period has advanced gradually, following the progress of absolute d...
Article
The varved sediments of Lake Montcortès (central pre-Pyrenees) have provided a continuous high-resolution record of the last ca. 3000 years. Previous chronological and sedimentological studies of this record have furnished detailed paleoenvironmental reconstructions. However, palynological studies are only available for the last millennium, when th...
Chapter
The Basin of Mexico is a high elevation (2240 m asl), large (9540 km2), tectonic endorheic basin developed in the central-eastern Trans-Mexican Volcanic Belt. In 2016, the ICDP MexiDrill project recovered a total of 1152 m of sediments from a maximum depth of 520 m in Lake Chalco, in the SW of the Basin of Mexico. The upper 309.15 m (composite sequ...
Conference Paper
Full-text available
Weather modification by means of cloud seeding techniques is widely implemented across the world. In areas where hail suppression systems are installed, silver iodide (AgI) particles are used. Silver particles fall back to the surface thank to atmospheric deposition. In this research we follow a holistic approach to analyse silver accumulation in w...
Article
The silver content in soils in the area in the surroundings of the Gallocanta Lake (Aragón, NE Spain) is lower than expected considering the estimated silver emission during the last 50 years by hail suppression systems. To understand the silver accumulation processes, selected water (4 surface, 3 groundwater), biota and sediment (6 surface sedimen...
Preprint
The varved sediments of Lake Montcortès (central Pre-Pyrenees) have provided a continuous high-resolution record of the last ca. 3000 years. Previous chronological and sedimentological studies of this record have furnished detailed paleoenvironmental reconstructions. However, palynological studies are only available for the last millennium, when th...
Article
Full-text available
The varved sediments of Lake Montcortès (central Pyrenees) have provided a continuous and well-dated high-resolution record of the last ca. 3000 years. Previous chronological and sedimentological studies of this record have furnished detailed paleoenvironmental reconstructions. However, palynological studies are only available for the last millenni...
Article
Lake Chalco lies south of the Basin of Mexico and has been the subject of studies related to Late Quaternary climate variability. In 2016, the International Continental Scientific Drilling Program “MexiDrill Project” recovered a 520-m sediment record from Lake Chalco. Magnetic susceptibility measurements revealed substantial changes in sediment phy...
Article
Dam-failure floods typically involve greater peak discharge than the largest meteorological flood at a basin. Determining the geomorphic effectiveness of extreme flooding caused by a breach mechanism provides insight into the role of flood scale on the resulting processes and landforms. Here, we present a geomorphological and hydraulic analysis of...
Article
Full-text available
Abrupt warming events recorded in Greenland ice cores known as Dansgaard-Oeschger (DO) interstadials are linked to changes in tropical circulation during the last glacial cycle. Corresponding variations in South American summer monsoon (SASM) strength are documented, most commonly, in isotopic records from speleothems, but less is known about how t...
Article
Full-text available
Deep sediment cores from long-lived lake basins are fundamental records of paleoenvironmental history, but the power of these reconstructions has been often limited by poor age control. Uranium-thorium (U-Th) dating has the potential to fill a gap in current geochronological tools available for such sediment archives. We present our systematic appr...
Article
Full-text available
Few continental palaeoenvironmental sedimentary sequences from Southern Europe are long enough to span the last interglacial period (Marine Isotopic Stage-MIS 5), the last glacial cycle (MIS 4 to 2) and the Holocene. El Cañizar de Villarquemado (North-Eastern Iberian Peninsula) is an exceptional sedimentary lacustrine sequence spanning the last ca....
Article
We have analyzed potential harmful trace elements (PHTE; Pb, Hg, Zn, As and Cu) on sediment cores retrieved from lake Marboré (LM) (2612 m a.s.l, 42°41′N; 0° 2′E). PHTE variability allowed us to reconstruct the timing and magnitude of trace metal pollutants fluxes over the last 3000 years in the Central Pyrenees. A statistical treatment of the data...
Article
Full-text available
Late Quaternary volcanic basins are active landscapes from which detailed archives of past climate and seismic and volcanic activity can be obtained. A multidisciplinary study performed on a transect of sediment cores was used to reconstruct the depositional evolution of the high-elevation Laguna del Maule (LdM) (36∘ S, 2180 m a.s.l., Chilean Andes...
Article
Full-text available
Human activities have profoundly altered the global nutrient cycle through Land Use and Cover Changes (LUCCs) since the industrial revolution and especially during the Great Acceleration (1950 CE). Yet, the impact of such activities on terrestrial and aquatic ecosystems above their ecological baselines are not well known, especially when considerin...
Preprint
Full-text available
Abstract. Late Quaternary volcanic basins are active landscapes from which detailed archives of past climate, seismic and volcanic activity can be obtained. A multidisciplinary study performed on a transect of sediment cores was used to reconstruct the depositional evolution of the high-elevation Laguna del Maule (LdM) (36° S, 2180 m asl, Chilean A...
Preprint
*----- NOTE: This is a non-peer reviewed preprint. The manuscript has been submitted as an invited research article to Quaternary Science Reviews and is under peer review. -----* Deep sediment cores from long-lived lake basins are fundamental records of paleoenvironmental history, but the power of these reconstructions has often been limited by poo...
Preprint
A sediment core spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes reveals abrupt climatic events on a centennial-millennial time scale. These events, which involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake, occurre...
Article
Full-text available
The primary scientific objective of MexiDrill, the Basin of Mexico Drilling Program, is development of a continuous, high-resolution ∼400 kyr lacustrine record of tropical North American environmental change. The field location, in the densely populated, water-stressed Mexico City region gives this record particular societal relevance. A detailed p...
Article
Full-text available
Modern precipitation anomalies in the Altiplano, South America, are closely linked to the strength of the South American summer monsoon (SASM), which is influenced by large-scale climate features sourced in the tropics such as the Intertropical Convergence Zone (ITCZ) and El Niño–Southern Oscillation (ENSO). However, the timing, direction, and spat...
Conference Paper
Full-text available
Pliocene Earth featured a warmer global temperature (+3-4 ° C), little Northern Hemisphere ice cover, and possibly pCO2 of ~400 ppm. During the Pliocene, multiple large perennial lakes existed for several million years in what is now arid and semi-arid Western United States (e.g. Lake Idaho, Idaho; Summer Lake, Oregon; Butte Valley, Tule Lake, Sear...
Chapter
Full-text available
The Permian-Triassic rifting represents the first of the two Mesozoic rifting stages recorded in the Iberian Peninsula. Its first phases of development started during the Early Permian, and were linked to the beginning of the break-up of Pangea, the large, unique and rheologically unstable supercontinent that mainly resulted from the collision of G...
Article
We present a multidisciplinary dating approach - including radiocarbon, Uranium/Thorium series (U/Th), paleomagnetism, single-grain optically stimulated luminescence (OSL), polymineral fine-grain infrared stimulated luminescence (IRSL) and tephrochronology - used for the development of an age model for the Cañizar de Villarquemado sequence (VIL) fo...
Article
Full-text available
Modern precipitation anomalies in the Altiplano region of South America are closely linked to the strength of the South American Summer Monsoon (SASM) which is influenced by large-scales climate components sourced in the tropics such as latitudinal shifts of the Intertropical Convergence Zone (ITCZ) and El Niño-Southern Oscillation (ENSO). However,...
Chapter
Full-text available
La humanidad ha transformado nuestro planeta durante milenios a través de cambios en el paisaje y en los ciclos biogeoquímicos debidos al uso de recursos naturales y a actividades como la agricultura, ganadería y la minería que pueden causar impactos como contaminación de aguas y suelos y deforestación, entre otros. La magnitud y extensión de estos...
Chapter
Full-text available
Los ecosistemas litorales se encuentran en un delicado equilibrio entre la influencia marina y terrestre, albergan una alta biodiversidad y ejercen un importante control sobre los ciclos y flujos biogeoquímicos entre los continentes y los océanos. Las proyecciones de cambio climático para los próximos 100 años señalan a estos ambientes como altamen...
Article
Varves provide annually resolved chronologies and high‐resolution reconstructions of environmental changes affecting human societies, both key issues for geoarchaeological research. Varve sequences occur in a wide range of depositional environments (mostly in marine, estuarine, and lacustrine settings). Most varve chronologies include the Holocene...
Article
We present the first Holocene chironomid-based summer temperature reconstruction for the Iberian Peninsula. A sequence from the shallow mountain lake Basa de la Mora (1914 m a.s.l., Central Pyrenees) was analysed and the reconstruction was performed by means of a merged Norwegian–Swiss chironomid calibration dataset. The presence of a multiproxy st...
Article
The study of three lacustrine sedimentary archives along an altitudinal transect in the Southern Central Pyrenees - lakes Estanya, Basa and Marboré- has provided a unique record of changes in anthropogenic trace metal concentrations over the last six centuries in NE Iberian Peninsula. Although site-specific processes influence metals enrichments in...
Article
Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to est...
Article
Full-text available
Sedimentological, geochemical and magnetic data in a ~ 7-m sequence from Marboré Lake (2612 m asl, central Pyrenees) provide information about environmental variability since the last glacier retreat (14.6 cal ka BP) in high-altitude Pyrenean environments. The sediment sequence is composed of millimeter- to centimeter-thick rhythmites made of finer...
Article
Abstract Comparison of selected, well-dated, lacustrine, speleothem and terrestrial pollen records spanning the Holocene onset and the Early Holocene (ca. 11.7–8 cal kyrs BP) in the Iberian Peninsula shows large hydrological fluctuations and landscape changes with a complex regional pattern in timing and intensity. Marine pollen records from Albora...
Article
Coastal back-barrier perched lakes are freshwater bodies that are elevated over sea-level and are not directly subjected to the inflow of seawater. This study provides a detailed reconstruction of the Doniños back-barrier perched lake that developed at the end of a small river valley in the rocky coast of the north-west Iberian Peninsula during the...
Article
Full-text available
Atmospheric relative humidity is an important parameter affecting vegetation yet paleo-humidity proxies are scarce and difficult to calibrate. Here we use triple oxygen (d17O and d18O) and hydrogen (dD) isotopes of structurally-bound gypsum hydration water (GHW) extracted from lacustrine gypsum to quantify past changes in atmospheric relative humid...
Conference Paper
The Mexidrill Project recovered four overlapping sediment cores from Lake Chalco in the Basin of Mexico, near Mexico City, to reconstruct this region’s paleoclimatic history. A composite core dated with a mixture of preliminary radiocarbon dates and tephrochronology suggests that Lake Chalco was present for several hundred thousand years at this lo...
Article
Full-text available
Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to est...
Article
The Little Ice Age (LIA) is known as one of the coldest stages of the Holocene. Most records from the Northern Hemisphere show evidence of significantly colder conditions during the LIA, which in some cases had substantial socio-economic consequences. In this study we investigated the magnitude and timing of climate variability during the LIA in th...
Article
Full-text available
Lake sediments constitute natural archives of past environmental changes. Historically, research has focussed mainly on generating regional climate records, but records of human impacts caused by land-use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to es...
Article
This paper presents the environmental, climate and vegetation changes reconstructed for the last 14.6 kyr cal BP from the Marbor? Lake sedimentary sequence, the highest altitude record (2612 m a.s.l.) in the Pyrenees studied up to date. We investigate the sensitivity of this high altitude site to vegetational and climate dynamics and altitudinal sh...