The persistence and role of basin structures on the 3D architecture of the Marañón Fold-Thrust Belt,Peru

The 3D architecture of fold-thrust belts commonly involves thin-skinned and thick-skinned deformation. Both thick- and thin-skinned deformation styles have been suggested to occur in the Marañón Fold-Thrust Belt (MFTB) in Peru, but the relative timing and strain partitioning associated with them are not well understood. We demonstrate that inherited basement structures along the Peruvian convergent margin reactivated during the evolution of the MFTB. We present results from field mapping, interpretation of remote sensing imagery, and cross section construction and restoration. The results show that the Chonta Fault, a median pre-folding basin normal fault, was inverted and acted as a mechanical buttress during initial east-vergent contraction of the fold-thrust belt. This fault separates the belt into two domains of distinctly different structural styles. During the Eocene, units to the west of the Chonta Fault deformed by folding, using the fault as a buttress, and subsequently propagated eastward by thin-skinned thrusting. This was followed in the Miocene by west-vergent, basement-involved deformation, which overprinted the earlier east-vergent, thin-skinned structures. The proposed tectonic model of the MFTB highlights the role of basement-fault reactivation during orogenesis and the involvement of deep structures in partitioning deformation styles.     

New rurality and the experience of place: the small rural locality of La Niña,Buenos Aires,Argentina

This paper presents a cultural geographic approach for understanding local social processes of territorial re-appropriation taking place in response to non-local forces and interests. This approach is applied to the small rural locality of La Niña, in Buenos Aires Province, Argentina. The small village of La Niña is currently in a locally-led process of recovering from a recent depopulation trend caused mainly by the irruption of transnational agribusiness. As economic opportunities have dwindled in the last decades, more recently local inhabitants and new settlers have set forth diverse strategies aimed at mitigating the effects of depopulation on the social structure. We focus our attention on the way the living experience of place is involved in all these strategies. We contend that despite economic and cultural homogenization caused by globalization, the experience of place is a permanent though ever-changing aspect of social life. Our research was based on archival and hemerographic surveys and ethnographic field techniques, encompassing participatory observation, semistructured and in-depth interviews with social and government leaders and local producers as well as field landscape appraisals.     

Geochronology of Yanshanian Magmatism and Metamorphism in the Hinterland of the Dabie Mountains and Their Geologic Implications

A strong tectono-magmatic thermal event has been revealed by field observations of granitic, migmatiticand metamorphic rocks in the hinterland of the Dabie Mountains. K-Ar, Ar-Ar and Rb-Sr determinationsshow that the event took place 133-117 Ma ago (Yanshanian). Contemporaneously, a southwestwardthrust-type ductile shearing at multiple levels occurred in the lower crust or at even deeper levels, suggestingthat the Dabie Mountains region was still under the influence ot strong continent-continent overlappingtectonism of the Yangtze block under the Sino-Korean block at depth. Metamorphic rocks of amphibolitefacies, migmatites and deep structural deformations resulting from this tectonothermal event are now exposedto the surface. The present features of the Dabie Mountains thus have appeared only since ca. 100 Ma B.P. Theblock composed of the Dabie Group is not an uplift or shield which would have undergone a long-continuederosion.     

Geochemical distribution of arsenic,cadmium, lead and zinc in river sediments affected by tailings in Zimapán,a historical polymetalic mining zone of México

High arsenic (As) groundwater is widely distributed in northwestern Hetao Plain, an arid region with sluggish groundwater flow. Observed As concentration in groundwater from wells ranges from 76 to 1,093 μg/l. Most water samples have high total dissolved solids, with Cl and HCO₃ as the dominant anions and Na as the dominant cation. The major hydrochemical types of most saline groundwaters are Na–Mg–Cl–HCO₃ and Na–Mg–Cl. By contrast, fresh groundwaters generally belong to the Na–Mg–HCO₃ type. High concentrations of arsenic in shallow aquifers are associated with strongly reducing conditions, as evidenced by high concentrations of dissolved organic carbon, ammonium, as well as dissolved sulfide and Fe, dominance of arsenite, relatively low concentrations of nitrate and sulfate, and occasionally high content of dissolved methane (CH₄). High As groundwaters from different places at Hetao Plain experienced different redox processes. Fluoride is also present in high As groundwater, ranging between 0.40 and 3.36 mg/l. Although fluorosis poses an additional health problem in the region, it does not correlate well with As in spatial distribution. Geochemical analysis indicates that evapotranspiration is an important process controlling the enrichment of Na and Cl, as well as trace elements such as As, B, and Br in groundwater. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Comparative hydrochemistry of five nested catchments located in the upper part of the Barcés river watershed (A Coruña,NW Spain)

259 stream water and 21 bulk precipitation samples have been studied between April 2008 and December 2010 in order to assess baseline hydrochemical conditions in a rural area of NW Spain. Stream waters are related to five nested catchments (<10 km²) with apparent low mean residence times. Their hydrochemical characteristics are closely related to bulk precipitation although clear evidences of seasonal (flushing, dilution, sediment desorption, etc.), lithological (schist vs. granite substrate) and anthropogenic (land use, contamination) effects are also described.     

Relative age of Cordilleran base metal lode and replacement deposits, and high sulfidation Au–(Ag) epithermal mineralization in the Colquijirca mining district, central Peru

At Colquijirca, central Peru, a predominantly dacitic Miocene diatreme-dome complex of 12.4 to 12.7 Ma (⁴⁰Ar/³⁹Ar biotite ages), is spatially related to two distinct mineralization types. Disseminated Au–(Ag) associated with advanced argillic alteration and local vuggy silica typical of high- sulfidation epithermal ores are hosted exclusively within the volcanic center at Marcapunta. A second economically more important mineralization type is characterized as "Cordilleran base metal lode and replacement deposits." These ores are hosted in Mesozoic and Cenozoic carbonate rocks surrounding the diatreme-dome complex and are zoned outward from pyrite–enargite–quartz–alunite to pyrite–chalcopyrite–dickite–kaolinite to pyrite–sphalerite–galena–kaolinite–siderite. Alunite samples related to the Au–(Ag) epithermal ores have been dated by the ⁴⁰Ar/³⁹Ar method at 11.3–11.6 Ma and those from the Cordilleran base metal ores in the northern part of the district (Smelter and Colquijirca) at 10.6–10.8 Ma. The significant time gap (~0.5 My) between the ages of the two mineralization types in the Colquijirca district indicates they were formed by different hydrothermal events within the same magmatic cycle. The estimated time interval between the younger mineralization event (base metal mineralization) at ~10.6 Ma and the ages of ~12.5 Ma obtained on biotites from unmineralized dacitic domes flanking the vicinity of the diatreme vent, suggest a minimum duration of the magmatic–hydrothermal cycle of around 2 Ma. This study on the Colquijirca district offers for the first time precise absolute ages indicating that the Cordilleran base metal lode and replacement deposits were formed by a late hydrothermal event in an intrusive-related district, in this case post Au–(Ag) high-sulfidation epithermal mineralization.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.Editorial handling: O. Christensen     

Geology and petrology of the Austroalpine Châtillon slice,Aosta valley,western Alps

Slices of continental crust pertinent to the lower Austroalpine domain of the western Alps, crop out within the ophiolitic Piemonte Zone. Among them, the Châtillon slice was studied in detail. The slice consists of orthogneiss with subordinate metabasics and very minor paraschist. The garnet-phengite-epidote-albite orthogneiss is characterised by polyphase garnet porphyroclasts. Metabasics consist of prasinite lenses and eclogite relics. Phengite-clinozoisite eclogite is characterised by small garnet idioblasts with prograde zoning; jadeite content in omphacite increases towards the rim; Si content in phengite decreases towards the rim. Garnet-glaucophane-phengiteparagonite micaschist is characterised by polymetamorphic garnet porphyroclasts, and small Alpine garnet idioblasts. A pre-Alpine amphibolite-facies metamorphism is inferred for the polymetamorphic rocks of the Châtillon slice. Paragneiss and micaschist probably derive from pre-Alpine “kinzigites”; the orthogneiss protolith was a late-Variscan porphyritic granitoid. Thermobarometry in the eclogite constrains the metamorphic peak at T ≤ 560 °C and P = 16 kbar. The HP minerals were partly retrogressed to greenschist-facies assemblages during the late Alpine tectono-metamorphic recrystallisation. The inferred Alpine P-T conditions are consistent with those for other Penninic and Austro-Alpine nappes of the northwestern internal Alps. The Châtillon slice is very similar to the Eclogitic Micaschists Complex of the Sesia-Lanzo Zone and to the other eclogite-facies Austroalpine slices of the Dent Blanche Nappe, but it could also represent a portion of the Sesia-Lanzo Zone basement, which experienced a somewhat different subduction depth. The tectonic position of the Châtillon slice within the Piemonte Zone is essential to reconstruct the geometric relationships in the Austroalpine-Piemonte nappe stack of the northwestern internal Alps.     

Identifying sources of groundwater in the lower Colorado River valley, USA, with δ18O, δD, and 3H: implications for river water accounting

Isotope measurements (¹⁸O, D, ³H) indicate groundwater origin in the Lower Colorado River Valley (LCRV) and provide an alternative, or supplement, to the US Bureau of Reclamations proposed accounting surface method. The accounting surface method uses a hydraulic criterion to identify certain wells away from the flood plain that will eventually yield mainstream Colorado River water. New isotope data for 5 surface-water and 18 groundwater sites around Topock Marsh, Arizona, are compared with river-water data (1974–2002) from 11 sites between Utah and Mexico and with groundwater data from previous LCRV studies. Three groundwater sources are repeatedly identified in the LCRV: (1) local recharge derived from precipitation, usually winter rain, plots slightly below the global meteoric water line (GMWL) and has D values that are 20 greater than those of recent river water; (2) older (pre-1950) upper basin river-water plots on or near the GMWL, distinct from local rainfall and recent river water; and (3) recent (post-1950) Colorado River water, including Topock Marsh samples, plots below the GMWL along an evaporation trend. Large floods, as in 1983, complicate interpretation by routing less evaporated upper basin water into the LCRV; however, tritium content can indicate the age of a water. River-water tritium has declined steadily from its peak of 716 TU in 1967 to about 11 TU in 2002. Mixtures of all three groundwater sources are common.

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Resumen Mediciones isotópicas (¹⁸O, D, ³H) indican cual es el origen del agua subterránea en el Valle Bajo del Río Colorado (LCRV) y aportan una alternativa, o complemento, para el método superficie de conteo propuesto por el Buró de Reclamación de Estados Unidos. El método superficie de conteo utiliza un criterio hidráulico para identificar ciertos pozos alejados de la planicie de inundación que eventualmente producirán agua a partir de la corriente principal del Río Colorado. Los nuevos datos isotópicos para 18 sitios de agua subterránea y 5 sitios de agua superficial cerca de los Pantanos Topock, Arizona, se comparan con datos de agua de río (1974–2002) provenientes de 11 sitios localizados entre Utah y México, y con datos de aguas subterráneas de estudios previos realizados en el LCRV. Se identifican reiteradamente tres fuentes de aguas subterráneas en el LCRV: (1) recarga local derivada de precipitación, generalmente lluvia de invierno, cuya composición cae ligeramente por debajo de la línea de agua meteórica global (GMWL) y tiene valores D que son 20 mayores que los reportados para agua de río reciente; (2) el agua de río más vieja (pre-1950) de la cuenca alta cuya composición cae sobre o cerca de la GMWL, diferente de la lluvia local y del agua de río reciente; (3) agua reciente (post-1950) del Río Colorado, incluyendo muestras de los Pantanos Topock, con composición por debajo de la GMWL a lo largo de una tendencia a la evaporación. Inundaciones grandes, como en 1983, complican la interpretación al transmitir menos agua evaporada de la cuenca alta hacia el LCRV; sin embargo, el contenido de tritio puede indicar la edad del agua. El contenido de tritio en agua de río ha disminuido constantemente desde la concentración pico de 716 TU en 1967 a cerca de 11 TU en 2002. Es común que exista mezclas de las tres fuentes de agua subterránea.

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Résumé Les mesures isotopiques (d18O, dD, 3H) indiquent les origine de leaux souterraines dans la Vallée de la Rivière du Bas Colorado (LCRV) et sont une alternative, ou un supplément, à la méthode des bilans hydrologiques proposée par du «US Bureau of Reclamation». Cette méthode de bilan hydrologique utilise un critère hydraulique permettant didentifier certains puits hors de la plaine dinondation qui pomperaient une part non négligeable de leur eau dans la rivière Colorado. De nouvelles données isotopiques provenant de 5 sites deau de surface et 18 deaux souterraines autour de Topock Marsh en Arizona, sont comparées avec les données (1974–2000) de 11 sites localisés entre Utah et Mexico, ainsi que des données dautres études sur la LCRV. Ces sources deaux souterraines sont identifiées à plusieurs reprises dans la LCRV: (1) la recharge locale dérivant des précipitations, généralement les pluies hivernales, se retrouvent légèrement sous la ligne deau météoritique globale (GMWL) et possède des valeurs de dD 20% supérieures aux valeurs des eaux récentes de la rivière; (2) les eaux vieilles (pre-1950) du bassin supérieur de la rivière possèdent une valeurs très proches de la GMWL, distinctes des valeurs de la pluie locale et des eaux récentes de la rivière; et (3) les eaux récentes (post-1950) de la Rivière Colorado, incluant les échantillons de Topock Marsh, se positionnent à côté de la GMWL sur une droite dévaporation. Les grandes inondations, par exemple celle de 1983, compliquent linterprétation en reprenant dans la LCRV moins deaux marquées comme évaporées et provenant du bassin supérieur; par ailleurs le pic de tritium est descendu de 716 TU en 1967 à 11 TU en 2002. Les mélanges de ces trois sources sont assez fréquentes.

     

Bankline change and the facets of riverine hazards in the floodplain of Subansiri–Ranganadi Doab, Brahmaputra Valley, India

Subansiri?CRanganadi Doab (confluence country), located in Lakhimpur district, Assam, is one of the worst flood-affected areas in Brahmaputra valley. The Doab is well populated, and land around these rivers is extensively used for cultivation. As means of flood protection, embankments were constructed in the 1950s along the banks of both the rivers. On the other hand, these rivers are dynamic in terms of banklines and other forms of channel changes. Progressive migration of bankline, due to erosion, results in loss of cultivable land. Moreover, it causes breaches in the embankments increasing the severity of flood in the Doab. This paper attempts to study the changes in the banklines of two major rivers in the floodplains of the Subansiri?CRanganadi Doab during 1997?C2009 in the context of the riverine hazards it brings to the floodplain dwellers. The shift of the banklines in Subansiri?CRanganadi Doab, downstream of North Lakhimpur, has been estimated using IRS LISS imageries of 1997 and 2009 in GIS environment. The river Subansiri during the study period has migrated westward and has widened substantially resulting in erosion of an area of ~19.137?km². For Ranganadi, the total area that has been eroded due to channel changes is ~0.897?km². The channel changes are mainly due to concave bank erosion associated with high stages of flow. Channel widening in Subansiri and Ranganadi in the study area during the decades of 1990s and 2000 has led to frequent breaches in the embankments. Lateral erosion and inundation due to embankment failure are the most dominant facets of riverine hazards in the study area as these lead to loss of livelihood. Therefore, it is necessary to incorporate geomorphic changes in formulating flood management programmes.     

Deep structure and volcanic activity of Mount Elbrus and a portion of the Elbrus–Tyrnyauz valley: Geological and geophysical data

Doklady Earth Sciences - A microseismic sounding profile was made along the Baksan River valley from the eastern summit of Elbrus volcano to the southern edge of town Tyrnyauz. The geological...     

Energy gradient and geomorphological processes along a river influenced by neotectonics (the Saône river,France)

The purpose of this study is to link the sediment transit and the flood plain storage of the Saône to hydromorphological characteristics of the hydrosystem, which exemplifies a new approach to sediment dynamics. The study of suspended sediment concentration in terms of temporal evolution, together with sediment deposition in terms of spatial variability, is a way to record the longitudinal evolution of the sediment load, which expresses the available energy gradient from upstream to downstream in hydrosystem. The Saône river is a 480-km-long Rhone tributary, with an oceanic pluvial regime, and an average yearly discharge of 440 m s⁻¹ at Lyons. The watercourse is characterised by very gentle slopes controlled by the neotectonics of the Bresse trough and by Holocene fluvial dynamics. Sediments were sampled during the December 1993–January 1994 flood (2 375 m³ s⁻¹) and the 1995 January–February flood (1 826 m³ s⁻¹). A fine partition into homogeneous sectors, using stream power as well as shear stress, has been realized on a 400 km reach using longitudinal and cross-sections at one kilometre intervals. This partition, compared with the results of the field sampling, shows that the amount of energy is closely connected to the hydromorphological characteristics of the river.     

Salt and nitrate exports from the sprinkler-irrigated Malfarás creek watershed (Ebro river valley,Spain) during 2010

Irrigated agriculture is a clear source of non-point pollution by salts and nitrogen species. The impact of such pollution should be quantified according to specific cases. The case of the Malfarás creek basin, a sprinkler irrigation district located in the semiarid Ebro valley in northeast Spain, has been evaluated. The main crops in the district were corn, barley and alfalfa, occupying 93 % of the irrigated area. The fate of water, salts and nutrients was evaluated by a daily water balance developed at a field scale for the natural year 2010. The yearly data of the whole set of 101 irrigated fields plus the non-irrigated area compared to the measured drainage produced a basin water balance with a low degree of error. The basin consumed 90 % of the total water input of which 68 % was used for crop evapotranspiration and the rest was lost due to non-productive uses. 16 % of the incoming water left the irrigation area as drainage water. The irrigated area was responsible for 87 % of the drainage. The average volume of drained water was 152 mm year^?1 for the whole basin area. The irrigated area drained 183 mm year^?1. The basin exported 473 kg of salt per hectare during 2010. This value was the lowest of the sprinkler irrigation areas in the Ebro valley, mainly due to the lower soil salinity. All the crops except barley received a nitrogen surplus of 10–50 % above their needs. The extra nitrogen entered the water cycle increasing the nitrate concentration in the aquifer water (150 mg L^?1) and drainage water (98 mg L^?1). In 2010 the mass of nitrogen exported by drainage was 49 kg per irrigated hectare. This value is too high for this type of irrigation system and implies that 17 % of nitrogen applied as a fertilizer was lost to drainage water. The key to decreasing the nitrogen leaching and pollution that it causes could be appropriate time-controlled fertigation along with better irrigation scheduling.     

Mercury concentrations in a contaminated river system in Kazakhstan and biomonitoring of the local population

The River Nura in central Kazakhstan has been heavily contaminated by mercury （Hg） from an acetaldehyde plant located in the industrial city of Temirtau. The plant released Hg-containing wastewater into the river from the 1950s until the mid 1990s and strongly contaminated the bed sediments up to 25 km downstream. In addition, a local power station released an estimated 6 million tonnes of fly-ash into the water which has adsorbed much of the Hg and has become mixed with the natural sediments. River water,fish and agricultural land in the floodplain are also contaminated by Hg. Humans are exposed to Hg primarily via the consumption of contaminated fish from the river. A survey was undertaken in June/July 2005 to investigate Hg concentrations in river water, drinking water, sediments and fish. To estimate the risk posed to the local population, approximately 300 hair samples were collected from people living in villages near the most contaminated section of the river, at a distance of between 5 and 30 km downstream of the acetaldehyde plant, and their dietary habits were recorded. Mercury concentrations in river water ranged from 2-3 ng/L upstream of the source of the pollution to 348 ng/L downstream of the factory outfall pipe. Some drinking water wells close to the river were contaminated, but deeper wells had Hg concentrations below the detection limit.     

“You kill the dam,you are killing a part of me”: Dam removal and the environmental politics of river restoration

River restoration through dam removal provides an opportunity to investigate the changing nature of environmental conflicts and politics in long-humanized landscapes. In New England, where over 14,000 dams fragment the region’s rivers, dam removals are often highly contested. This is due, in part, to how the intertwined roles of history, identity, and aesthetics coalesce to create attachment to place and inspire the defense of dammed landscapes. Dam removal provides a useful lens to consider the following: How do the historical and geographical contingencies of this region shape and alter conflicts over dam removal in specific ways? In instances where conflicts emerge, what do the conflicts reveal about the politics of ecological restoration in highly altered landscapes? We use a political ecology approach to reveal how complex cultural dynamics, competing interpretations of science and the environment, micropolitics, and the role of multiple actors generate and shape conflicts over dam removal. We show that the historical geography of New England influence conflicts over removal in important ways, particularly with regard to the roles of aesthetics and identity in landscapes that are characterized largely by consumptive as opposed to productive uses. Our findings also suggest that restoration in long-humanized landscapes will embroil new constellations of human and nonhuman actors, requiring attention to the political and cultural, as well as the ecological, dimensions of restoration. This paper contributes to research on the political and social dimensions of dam removal, as well as to research at the nexus of ecological restoration and environmental politics.     

Groundwater mining of bedrock aquifers in the Denver Basin – past,present, and future

The Denver Basin bedrock aquifer system is an important source of water for municipal and agricultural uses in the Denver and Colorado Springs metropolitan areas. The Denver area is one of the fastest growing areas in the United States with a population of 1.2 million in 1960 that has increased to over 2.4 million by 2000. This rapid population growth has produced a corresponding increase in demand for potable water. Historically, the Denver area has relied on surface water, however, in the past 10 years new housing and recreation developments have begun to rely on groundwater from the bedrock aquifers as the surface water is fully appropriated and in short supply.The Denver Basin bedrock aquifer system consists of Tertiary and Cretaceous age sedimentary rocks known as the Dawson, Denver, Arapahoe and Laramie-Fox Hills Aquifers. The number of bedrock wells has increased from 12,000 in 1985 to 33,700 in 2001 and the withdrawal of groundwater has caused water level declines of 76 m. Water level declines for the past 10 years have ranged from 3 to 12 m per year. The groundwater supplies were once thought to last 100 years but there is concern that the groundwater supplies may be essentially depleted in 10 to 15 years in areas on the west side of the basin.Extensive development of the aquifer system has occurred in the last 25 years especially near the center of the basin in Douglas and El Paso Counties where rapid urban growth continues and surface water is lacking. Groundwater is being mined from the aquifer system because the discharge by wells exceeds the rate of recharge. Concern is mounting that increased groundwater withdrawal will cause water level declines, increased costs to withdraw groundwater, reduced well yield, and reduced groundwater storage. As the long-term sustainability of the groundwater resource is in doubt, water managers believe that the life of the Denver Basin aquifers can be extended with artificial recharge, water reuse, restrictions on lawn watering, well permit restrictions and conservation measures.     

Characterization and facies analysis of the hydrovolcanic deposits of Montaña Pelada tuff ring: Tenerife,Canary Islands

Montaña Pelada is a basaltic Pleistocene tuff ring located in the SE of Tenerife and it is composed of two edifices each with its distinct internal depositional distribution. A detailed stratigraphic analysis was carried out and ten facies were recognized. Deposits interpretation has revealed that water/magma ratio changes controlled the eruptive evolution, distinguishing three main stages of the eruption. Pyroclastic density currents were formed during the initial phreatomagmatic stages depositing the proximal facies, and transformed into turbulent dry surges during the second stage, indicating a reduction in the water/magma ratio. After deposition of these surges, the opening of an N–S fracture drove the eruption northwards creating a new edifice. The new hydrological conditions allowed the input of phreatic water, which resulted in high proportion of accidental lithics within characteristic of the deposits, increasing the water/magma ratio and reducing the fragmentation degree as can be recognized in the third stage. The evolution of the second tuff was similar, starting with radial-diluted pyroclastic surges and finishing with base surges deposits, suggesting lower water/magma ratio and higher fragmentation degree. Whereas the south cone originates dry pyroclastic surges and many tuff facies, northern one does not go beyond the deposition of a laminated tuff.     

The Antarctic viewpoint of the Central Paratethys: cause, timing, and duration of a deep valley incision in the Middle Miocene Alpine–Carpathian Foredeep of Lower Austria

Global, glacio-eustatic sea-level changes massively influenced the depositional history of the Central Paratethyan region. Here, we correlate Middle Miocene global δ¹⁸O-shifts with ice volume changes on Antarctica and sea-level changes with corresponding phases of erosion (valley incision) and deposition in the Lower Austrian part of the Alpine–Carpathian Foredeep. This allows the exact dating of the valley formation. Two periods of positive δ¹⁸O-shifts resulted in sea-level drops of about 60 and 40 m, respectively. The first drop in the late Langhian (middle Badenian) at c. 13.9 Ma (Mi3b) was fast and caused severe erosion on the emerged foredeep. In a second, less pronounced step around 13.0 Ma (Mi4) in the middle Serravallian (late Badenian), the base level was further deepened after a period of alternating erosion and deposition. The combined sea-level change (80–120 m) fits well with the maximum thickness of Sarmatian sediments drilled within incised valley (110 m). The global sea-level falls affected not only the geological history of the foredeep. The intensive erosion (valley incision) is combined with delta progradation in the adjacent Vienna Basin. Due to this massive sea-level drop, the interruption of marine connections resulted in vast salt deposits and faunal crises within the Central Paratethys during this time.     

10Be dating of river terraces of Santo Domingo river,on Southeastern flank of the Mérida Andes,Venezuela: Tectonic and climatic implications

In this study, we discuss the first cosmogenic ¹⁰Be dating of river terraces located in the lower reaches of the Santo Domingo river (Southeastern flank of the Mérida Andes, Western Venezuela). The geomorphic observations and dating allowed the restoration of the temporal evolution of incision rate, which was analysed in terms of tectonic, climatic and geomorphic processes. The long-term incision rate in the area has been constantly around 1.1 mm/a over the last 70 ka. Taking into account the geologic and geomorphologic setting, this value can be converted into the Late Pleistocene uplift rate of the Southeastern flank of the Mérida Andes. Our results show that the process of terraces formation in the lower reaches of the Santo Domingo river occurred at a higher frequency (10³–10⁴ years) than a glacial/interglacial cycle (10⁴–10⁵ years). According to the global and local climate curve, these terraces were abandoned during warm to cold transitions.     

Relation between the variations in the global surface temperature,El Niño/La Niña phenomena,and the Atlantic Multidecadal Oscillation

We analyzed directed couplings between the variations in the global surface temperature and modes of the natural climatic variability: the El NiñoLa Niña (ENSO) quasi-periodical phenomena and the long-period Atlantic Mutidecadal Oscillation (AMO) based on the data for 1870–2014. According to the quantitative estimates based on the monthly and annual mean data, the initial data, and the 10-year mean remote data, the most pronounced impact of the ENSO on the global surface temperature and the AMO was found. A weaker bidirectional coupling between the global surface temperature and the AMO is also pronounced. The analysis using running windows revealed an alternating effect of the ENSO and AMO on the variations in the global surface temperature related to the AMO phases.