980 resultados para TRANSANTARCTIC MOUNTAINS


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Stable water isotope (delta(18)O, deltaD) data from a high elevation (5100 masl) ice core recovered from the Tien Shan Mountains, Kyrgyzstan, display a seasonal cycle in deuterium excess (d = deltaD - 8* delta(18)O) related to changes in the regional hydrologic cycle during 1994 - 2000. While there is a strong correlation (r(2) = 0.98) between delta(18)O and dD in the ice core samples, the regression slope (6.9) and mean d value (23.0) are significantly different than the global meteoric water line values. The resulting time-series ice core d profile contains distinct winter maxima and summer minima, with a yearly d amplitude of similar to 15 - 20parts per thousand. Local-scale processes that may affect d values preserved in the ice core are not consistent with the observed seasonal variability. Data from Central Asian monitoring sites in the Global Network of Isotopes in Precipitation (GNIP) have similar seasonal d changes. We suggest that regional-scale hydrological conditions, including seasonal changes in moisture source, transport, and recycling in the Caspian/ Aral Sea region, are responsible for the observed spatial and temporal d variability.

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Time-space relations of extension and volcanism place critical constraints on models of Basin and Range extensional processes. This paper addresses such relations in a 130-km-wide transect in the eastern Great Basin, bounded on the east by the Ely Springs Range and on the west by the Grant and Quinn Canyon ranges. Stratigraphic and structural data, combined with 40Ar/39Ar isotopic ages of volcanic rocks, document a protracted but distinctly episodic extensional history. Field relations indicate four periods of faulting. Only one of these periods was synchronous with nearby volcanic activity, which implies that volcanism and faulting need not be associated closely in space and time. Based on published dates and the analyses reported here, the periods of extension were (1) prevolcanic (pre-32 Ma), (2) early synvolcanic (30 to 27 Ma), (3) immediately postvolcanic (about 16 to 14 Ma), and (4) Pliocene to Quaternary. The break between the second and third periods is distinct. The minimum gap between the first two periods is 2 Ma, but the separation may be much larger. Temporal separation of the last two periods is only suggested by the stratigraphic record and cannot be rigorously demonstrated with present data. The three younger periods of faulting apparently occurred across the entire transect. The oldest period is recognized only at the eastern end of the transect, but appears to correlate about 150 km northward along strike with extension in the Northern Snake Range-Kern Mountains area. Therefore the oldest period also is regional in extent, but affected a different area than that affected by younger periods. This relation suggests that distinct extensional structures and master detachment faults were active at different times. The correlation of deformation periods of a few million years duration across the Railroad Valley-Pioche transect suggests that the scale of active extensional domains in the Great Basin may be greater than 100 km across strike.

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This study provides a continuous lateglacial and Holocene record of diatom silica oxygen isotope changes (delta O-18(DIAT)) in a subalpine lake sediment sequence obtained from the Retezat Mts (Taul dintre Brazi, 1740 m a.s.l.). This through-flow, shallow, high-altitude lake with a surface area of only 0.4 ha has short water residence time and is predominantly fed by snowmelt and rainwater. Its delta O-18(DIAT) record principally reflects the oxygen isotope composition of the winter and spring precipitation, as diatom blooms occur mainly in the spring and early summer. Hence, changes in delta O-18(DIAT) are interpreted as seasonal scale changes: in the amount of winter precipitation. Low oxygen isotope values (27-28.5 parts per thousand) occurred during the lateglacial until 12,300 cal BP, followed by a sharp increase thereafter. In the Holocene delta O-18(DIAT) values ranged from 29 to 31 parts per thousand until 3200 cal BP, followed by generally lower values during the late Holocene (27-30 parts per thousand). Short-term decreases in the isotopic values were found between 10,140-9570, 9000-8500, 7800-7300, 6300-5800, 5500-5000 and at 8015, 4400, 4000 cal BP. After 3200 cal BP a decreasing trend was visible with the lowest values between 3100-2500 and after 2100 cal BP The general trend in the record suggests that contribution of winter precipitation was generally lower between 11,680 and 3200 cal BP, followed by increased contribution during the last millennia. The late Holocene decrease in delta O-18(DIAT) shows good agreement with the speleothem delta O-18, lake level and testate amoebae records from the Carpathian Mountains that also display gradual delta O-18 decrease and lake level/mire water table level rise after 3200 cal BR Strong positive correlation with North Atlantic circulation and solar activity proxies, such as the Austrian and Hungarian speleothem records, furthermore suggested that short-term increases in the isotopic ratios in the early and mid Holocene are likely connectable to high solar activity phases and high frequency of positive North Atlantic Oscillation indexes that may have resulted in decreased winter precipitation in this region.

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In 2005, two ice cores with lengths of 58.7 and 57.6 m respectively to bedrock were recovered from the Miaoergou flat-topped glacier (43 degrees 03 ' 19 '' N, 94 degrees 19 ' 21 '' E; 4512 m a.s.l.), eastern Tien Shan. Pb-210 dating of one of the ice cores (57.6 m) was performed, and an age of AD 1851 +/- 6 at a depth of 35.2 m w.e. was determined. For the period AD 1851-2005, a mean annual net accumulation of 229 +/- 7 mm w.e. a(-1) was calculated. At the nearby oasis city of Hami (similar to 80 km from the Miaoergou flat-topped glacier) the annual precipitation rate is 38 mm w.e. a(-1), hence glacial meltwater is a major water supply for local residents. The surface activity concentration of Pb-210(ex) was found to be similar to 400 mBq kg(-1), which is higher than observed at other continental sites such as Belukha, Russia, and Tsambagarav, Mongolia, which have surface activity concentrations of 280 mBq kg(-1). The Pb-210 dating agrees well with the chronological sequence deduced from the annual-layer counting resulting from the seasonalities of delta O-18 and trace metals for the period AD 1953-2005, and beta-activity horizons resulting from atmospheric nuclear testing during the period AD 1962-63. We conclude that Pb-210 analysis is a suitable method for obtaining a continuous dating of the Miaoergou ice core for similar to 160 years, which can also be applied to other ice cores recovered from the mountains of western China.

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Cet article aborde la transformation de régions de montagne en lieux de résidence remplaçant des secteurs économiques plus anciens (agriculture, industrie manufacturière, tourisme) dans les montagnes européennes. Il se place dans la perspective du développement régional et de son impact sur les ressources régionales fixes, le « capital territorial ». Cette nouvelle tendance affecte les montagnes européennes de deux manières, et participe à la formation de régions métropolitaines qui combinent centres métropolitains et environnements de loisirs fondés sur les attraits du paysage pour constituer de nouvelles entités intégrées. Au cours du processus, le paysage devient un bien de consommation nouveau et rare, qui joue un rôle dans l’accumulation du capital investi. L’article établit que les concepts d’esthétique du paysage et d’agréments ne suffisent pas à expliquer cette nouvelle dynamique, car ils méconnaissent les processus spatio-économiques ainsi que le rôle de la marchandisation du paysage pour les nouveaux résidents. Ces nouveaux résidents ont un profil plus « multilocal » que migrant. La multilocalité et l’usage sélectif des produits du paysage freinent le processus d’intégration, crucial pour entretenir et développer le capital territorial. On peut poser que la présence non permanente des nouveaux résidents risque d’affaiblir et non de renforcer les structures locales existantes. Il semble donc nécessaire de déployer des efforts particuliers auprès de chaque groupe de nouveaux résidents pour que de simples résidents à temps partiel deviennent des acteurs régionaux (au moins à temps partiel). De plus, le concept du développement régional centré sur les acteurs innovants doit être remis en question dans la mesure où l’aspect « consommation » domine le rapport du paysage.

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Local knowledge is crucial to both human development and environmental conservation. This is especially the case in mountain regions, where a combination of remoteness, harsh climatic conditions, rich cultural heritage, and high biological diversity has led to the development of complex local environmental knowledge systems. In the Andes for instance, rural populations mainly rely on their own environmental knowledge to ensure their food security and health. Recent studies conducted within Quechua communities in Peru and Bolivia showed that this knowledge was both persistent and dynamic, and that it responded to socio-economic and environmental changes through cultural resistance and adaptation. As this paper argues, combining local knowledge and so-called scientific knowledge – especially in development projects – can lead to innovative solutions to the socio-environmental challenges facing mountain communities in our globalized world. Based on experiences from the Andes, this paper will provide concrete recommendations to policymakers and practitioners for integrating local knowledge into development and natural resource management initiatives.

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Sirkeli Höyük is an ancient settlement located 40 km east of Adana on the left bank of the Ceyhan River in Plain Cilicia. The main mound covers an area of approximately 300×400 m and rises to a height of ca. 30 m above the level of the surrounding plain. Due to its strategic location overlooking a road that crosses the Misis mountains, Sirkeli Höyük always played an important role within Plain Cilicia. J. Garstang’s (1936-1937), B. Hrouda’s (1992-1996) and H. Ehringhaus’ (1997) excavations have shown that the site was occupied from the 4th to late 1st millennium B.C. Since 2006, a new Swiss-Turkish team is investigating Sirkeli Höyük again. Due to modern excavation techniques and an interdisciplinary approach, the architectural and material remains that have been uncovered by the new excavations have yielded much new information. Apart from a more precise pottery sequence, the new project has discovered an extensive lower town surrounded by an elaborate double city wall. The paper will summarize the results that have been gathered since 2006, with particular focus on the campaigns 2012-2013, and aims to show how they may contribute to the understanding of the cultural developments in this region.

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The excavation site Reigoldswil is located at 550 m above sea level on the Jura chain hillside in north-western Switzerland. The mountains divide the Rhine valley from an agriculturally rich region. The origin of the village lies in the early medieval time. Until now the skeletons of one cemetery have been morphologically studied. Around 216 individuals were excavated from under the foundation walls of a church and in the open field. They date to the 7/8th up to the 10th century. The striking part is the high amount of subadult (0-18 years) individuals with 58% (n=126). One of these children, an approximately 1.5 year old toddler from the 7th century, was buried in a stone cist. Its bones show morphological traces like porotic lesions of the greater wings of the sphenoidale, the squama, the mandibule and the scapula as new bone formation on both femora and tibiae. These signs could be an indicator for Möller-Barlow disease (Ortner 2003, Brickley and Ives 2008, Stark in press). As scurvy is associated with an insufficient intake of vitamin C, malnutrition must be assumed. A reason might be the geographic location or/and a harsh climat with crop failure and famine the first settler had to face. Besides the morphological diagnose amino acids of the bone collagen have been analyzed (Kramis et. al.). Further examinations, such as radiocarbon dating and stable isotope ratios (C, N, O, S) to specify nutrition, are planned.