February 2023
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85 Reads
Anthropocene
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February 2023
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85 Reads
Anthropocene
July 2020
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36 Reads
July 2020
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624 Reads
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21 Citations
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). The recovered 5 m composite sediment sequence includes two thick turbidite units (LT1 and LT2) and numerous tephra layers (23 ash and 6 lapilli). We produced an age model based on nine new 14C AMS dates, existing 210Pb and 137Cs data, and the Quizapú ash horizon (1932 CE). According to this age model, the relatively drier Early Holocene was followed by a phase of increased productivity during the mid-Holocene and higher lake levels after 4.0 ka cal BP. Major hydroclimate transitions occurred at ca. 11, 8.0, 4.0 and 0.5 ka cal BP. Decreased summer insolation and winter precipitation due to a southward shift in the southern westerly winds and a strengthened Pacific Subtropical High could explain Early Holocene lower lake levels. Increased biological productivity during the mid-Holocene (∼8.0 to 6.0 ka cal BP) is coeval with a warm–dry phase described for much of southern South America. Periods of higher lake productivity are synchronous to a higher frequency of volcanic events. During the Late Holocene, the tephra layers show compositional changes suggesting a transition from silica-rich to silica-poor magmas at around 4.0 ka cal BP. This transition was synchronous with increased variability of sedimentary facies and geochemical proxies, indicating higher lake levels and increased moisture at LdM after 4.0 ka cal BP, most likely caused by the inception of current El Niño–Southern Oscillation and Pacific Decadal Oscillation (ENSO–PDO) dynamics in central Chile.
January 2020
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396 Reads
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1 Citation
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 Andes). The recovered 5 m composite sediment sequence includes two thick turbidite units (LT1 and LT2) and numerous tephra layers (23 ash and 6 lapilli). We produced an age model is based on nine new 14C AMS date, existing 210Pb and 137Cs data and the Quizapú ash horizon (CE 1932). According to this age model, early Holocene were followed by a phase of increased productivity during the mid Holocene and higher lake levels after 4.0 ka BP. Major hydroclimate transitions occurred at ca. 0.5, 4.0, 8.0 and 11 ka BP. Decreased summer insolation and winter precipitation due to a southward shift in the Southern Westerly Winds and a strengthened Pacific Subtropical High could explain early Holocene lower lake levels. Increased biological productivity during the mid-Holocene (~ 8.0 to 6.0 ka) is coeval with a warm-dry phase described for much of southern South America. Periods of higher lake productivity are synchronous to higher frequency of volcanic events. During the late Holocene, the tephra layers shows compositional changes suggesting a transition from silica-rich to silica-poor magmas at around 4.0 cal ka BP. This transition was synchronous with increased variability of sedimentary facies and geochemical proxies, indicating higher lake levels and increased moisture at LdM after 4.0 cal ka BP, most likely caused by the inception of current ENSO/PDO-like dynamics in central Chile.
January 2018
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103 Reads
January 2018
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40 Reads
January 2018
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48 Reads
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1 Citation
January 2018
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132 Reads
May 2017
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205 Reads
High-resolution, multi-proxy lake records from Iberian Mediterranean mountains with robust chronologies have allowed the identification of centennial to decadal scale paleohydrological fluctuations during the last 2000 years within the Iberian Peninsula. The dataset illustrates sharp regional gradients and timing differences when compared to climate changes recorded in Northern European records. Furthermore, these fluctuations show a large internal variability both in terms of timing and paleohydrological history in the Iberian Peninsula. Several factors may be responsible for this variability, mainly the interplay between Atlantic (NAO fluctuations) and Mediterranean influences and geographic factors as latitudinal and altitudinal gradients which imply a complex mosaic. In spite of some uncertainties, the main paleohydrological phases in Iberian Peninsula during the last two millennia appear in most records: a humid Iberian-Roman period (IRHP, 650 BCE – CE 350) particularly wetter between CE 300 – 350, relatively colder and wet conditions during the Dark Ages (CE 500 – 900), a well characterized Medieval Climate Anomaly (MCA, CE 900 – 1300) with lower water levels but variable flood frequency, and a contrasting relatively wet Little Ice Age (LIA, CE 1300 – 1850) with forest spread in the mountains, stationary flood conditions and increased sediment delivery to the lacustrine basins. Periods of increased human pressure in the landscape occurred both during warmer phases (IRHP and MCA) and colder periods (LIA) with diverse environmental and human adaptive strategies.
March 2017
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93 Reads
... A period with increased flows into the lake and substantial variability in sedimentation is identified between~13 700 and 14 000 cal a BP, suggesting glacier retreat compared to the previous period. Nearby records show the dominance of colder and/or wetter conditions than the present during this interval of time (Kim et al., 2002;Kaiser et al., 2008;Maldonado et al., 2016;Frugone-Álvarez et al., 2020) and periods of stabilization and glacial retraction until the early Holocene (Lowell et al., 1995;Zech et al., 2007;Ward et al., 2015), in agreement with the sedimentological changes recorded in LDV core (Phases 1-3). These conditions are probably associated with a lesser influence of the SWWB in the area, and the increase of temperatures associated with the end of the LGM is probably amplified by a reduced sea-ice cover (Lowell et al., 1995;Lamy et al., 1999Lamy et al., , 2010. ...
July 2020
... In contrast to the eastern foothills of the Andes, the western slopes and upper mountain ranges of the Andes were drier during the early to mid-Holocene. The records from Laguna Aculeo and Laguna del Maule indicate extreme drought conditions in the early Holocene (8000-7000 BP) that extended with less intensity to approximately 5000-4000 BP (Frugone-Álvarez et al., 2020;Jenny et al., 2002). Following a transitional period, rainfall on the western slopes of the Andes has been more abundant during the last 2500-2700 BP (Fig. 2). ...
January 2020
... The middle Holocene (8-5 ka) was characterized by a further drying trend in south-central Chile 45,48,52,54,55 , as well as south of 50°S 10,11 . This trend is reflected by a 6-7‰ increase in δD wax values at 41°S suggesting a weaker influence of moisture from the high latitudes, although part of the D-enrichment (1‰) may be related to the concurrent 1°C SST warming (Fig. 2b). ...
March 2017
Journal of Quaternary Science
... The global effects of historical pollution are not just limited to Industrial Revolutions. Pre-Industrial metal pollution in the atmosphere and in human remains can be traced back to the Roman exploitation of metals [174][175][176][177][178] and prehistoric caves [179][180][181][182]. These co-selective processes across time merit investigation to perceive how cultural transitions cause historical changes in AMR. ...
February 2017
The Holocene
... Las estimaciones llevadas a cabo por Rivas et al., (2006) indican que la tasa de denudación en el Valle del Río Besaya (Cantabria) ascendería a 3,2 mm/año, frente a la tasa natural promedio en la zona de 0,01 mm/año. (Morellón et al., 2016) comparados con: C. evolución del Producto Interior Bruto (PIB) en España, D. variación media de las precipitaciones anuales totales en la costa cantábrica oriental (media móvil de 10 años) y E. nivel medio del mar en el mareógrafo de Santander (Marcos et al., 2005) Fig. 3 Irabien et al., (2008) and Bruschi et al., (2013)), B. lakes Enol (López--Merino et al., 2011) and La Cueva (Morellón et al., 2016) compared with: C. Gross Home Product (GDP) in Spain,, D. mean annual rainfall in the Eastern Cantabrian coast (10 yr moving average) and E. mean sea level measured in the tide gauge of Santander (Marcos et al., 2005) Los registros lacustres disponibles en zonas más altas de la región (La Cueva (Somiedo) y Enol) muestran tendencias similares en las tasas de sedimentación, pero también descensos notables desde la década de los años 90 del siglo pasado (López--Merino et al., 2011;Morellón et al. 2016), que indicarían un progresivo y reciente descenso en la presión humana (Fig. 3). Sin embargo, otros indicadores reflejan una tendencia progresiva a la eutrofización como resultado de los efectos sinérgicos del calentamiento global y el impacto humano en estas zonas. ...
January 2016
... Estudios en zonas de alta montaña de la península ibérica desvelan también incrementos en marcadores geomorfológicos, de contaminación por metales pesados, o presencia de microplásticos (e. g. Allen et al., 2019;Martínez Cortizas et al., 2012;Morellón et al., 2016). ...
June 2016
... Extended research has been conducted in post-fire settings, due to the severe alteration on soil and vegetation/land-use. Runoff and the derived sediment yield volumes are significantly affected by the volume and intensity of precipitation, with the negative correlation with the vegetation cover decreasing in post-fire settings [141,142]. It is well established that high-severity wildfires reduce soil aggregate stability and enhance soil erodibility [143,144]. ...
June 2016
CATENA
... Laguna de la Cruz (surface area = 1.4 ha; 132 m of diameter; Z max = 25 m) exhibits meromixis and the occurrence of 'whitings' during the summer (Vicente and Miracle, 1987;Dasi and Miracle, 1991;Miracle et al., 1992;Rodrigo et al., 1993;Julià et al., 1998;Romero-Viana et al., 2008, 2011). Short cores have been recently obtained from Lake Lagunillo del Tejo (Romero-Viana et al., 2009;López-Blanco et al., 2012), and the study of long cores from Lakes Tejo and La Parra is in progress by our team (Barreiro-Lostres et al., 2011;Barreiro-Lostres et al., 2013). Lake El Tobar is the largest karstic lake in the region, with a maximum depth of 20 m and a surface area of 70 ha. ...
January 2011
... The facies of the sediments accumulated in the lakes indicate environmental changes. Thus, climate change (Holmes et al., 1995;Oliveira et al., 2008;Barreiro-Lostres et al., 2013), the composition of the rocks of the catchment area (Oliveira et al., 2008;Develle et al., 2011), the sediment sources of various origins such as aeolian origin (Develle et al., 2011), the anthropogenic effects on the catchment area (Barreiro-Lostres et al., 2013;Schmidt et al., 2000), changes of the vegetation (Develle et al., 2011;Schmidt et al., 2000), changes of water level (Holmes et al., 1995), the intensity of sediment transportation (Barreiro-Lostres et al., 2013) and the relationship between denudation and accumulation (Li et al., 2010). However, they also reflect the change of state of the lake thus, the change of water level and water depth (Schmidt et al., 2000), that of water quality (Holmes et al., 1995;Develle et al., 2011), eutrophication (Obelič et al., 2005) or the changes of flora and fauna (Wantzen et al., 2008). ...
January 2013
Cuadernos de Investigacion Geografica
... This rate was substantially higher than our 80-year average, which may be due to the extremely large area of the watershed compared to Z3. In another study, Barreiro-Lostres et al. (2015) investigated human-climate interactions on SAR in a Mediterranean mountain lake in Spain, with a basin area of 11 km 2 and a MAP of 956 mm. The uplands are dominated by pine trees, while cereal fields are found at lower elevations. ...
July 2015
The Science of The Total Environment