Miracle-dz/UniFAR-FTUs huggingface dataset:
Single-grain cosmogenic 21Ne concentrations in fluvial sediments reveal spatially variable erosion rates

We evaluated the hypothesis that the spatial variation in erosion in a catchment is reflected in the distribution of the cosmogenic nuclide concentrations in sediments leaving the catchment. Using published data and four new 10Be measurements in fluvial sediment collected from the outlets of small river catchments, we constrained the spatial variability of erosion rates in the Gaub River catchment in Namibia. We combined these catchment-averaged erosion rates, and the mean slope values with which they are associated, in a digital elevation model (DEM)–based analysis to predict distributions of cosmogenic 21Ne concentrations in the sediment leaving the Gaub catchment. We compared these synthetic distributions with the distribution of concentrations of cosmogenic 21Ne (21NeC) in 32 quartz fluvial pebbles (16–21 mm) collected from the catchment outlet. The 21NeC concentrations span nearly two orders of magnitude (2.6–160 × 106 atoms/g) and are highly skewed toward low values. The DEM-based analysis confirms this skew—the measured 21NeC distribution plots within the envelope of distributions predicted for the catchment. This match between measured and synthetic 21Ne distributions implies that the measured distribution is a signature of the spatial variation in erosion rates.
The Effect of a Bottom Shelf Front upon the Generation and Propagation of Near-Inertial Internal Waves in the Coastal Ocean

Abstract A three-dimensional nonlinear baroclinic model in cross-sectional form is used to study the generation and propagation of wind-forced near-inertial internal waves in a coastal region in the presence of a bottom front. Initially calculations are performed with the front in an infinite domain region. By this means coastal effects are removed. The initial response is in terms of inertial oscillations in the surface layer. However, in the frontal area these are modified by interaction through the nonlinear momentum terms with regions of positive and negative vorticity associated with the alongfront flow. This leads to a change in amplitude, phase, and frequency of the inertial current, and a resulting Ekman pumping that drives near-inertial internal waves in the frontal region. On the positive vorticity side of the front these waves are at the superinertial frequency and rapidly propagate away. On the negative side they are at the subinertial frequency and are trapped and inertial energy leaks to dep.
Trend analysis of surface cloud‐free downwelling long‐wave radiation from four Swiss sites

[1] We present a trend analysis of surface cloud-free downwelling long-wave radiation provided by pyrgeometer measurements of four stations of the Alpine surface radiation budget network in Switzerland. The stations cover an altitude range between 370 and 3580 meters above sea level. Cloud-free downwelling long-wave radiation, screen-level temperature, and relative humidity were selected from 10 min measurements, and monthly means were calculated. We performed two distinct trend analyses: the annual overall trend was determined applying least squares fitting, whereas nonparametric statistical methods were used to calculate the monthly trends. The cloud-free downwelling long-wave radiation time series shows a consistent and significant increase of 3.5 W m−2 per decade in the last 12 years at all four stations. The monthly trend analysis of the downwelling long-wave radiation revealed trend estimates exceeding the overall trend by a factor of 4 and partly with opposite signs. The monthly trends of the downwelling long-wave radiation are in agreement with the trends observed in screen-level temperature and specific humidity which have been determined using the same statistical methods. By applying a parameterization of cloud-free downwelling long-wave radiation, we quantitatively inferred the causes for the observed cloud-free trends. More than 50% of the downwelling long-wave radiation trends can be explained with the observed variations of temperature and humidity. There is some indication that the radiative effect of high-level clouds has changed and considerably contributed to the downwelling long-wave radiation trends that are not induced by screen-level temperature and humidity.
An indirect lead isotope age determination of gold mineralization at the Corinthia mine, Yilgarn Block, Western Australia

The Corinthia lode‐gold deposit in amphibolite‐facies greenstone belt rocks in the Southern Cross Province of the Archaean Yilgarn Block contains a largely undeformed pegmatite dyke emplaced during the last phases of movement along the Fraser's‐Corinthia shear zone. Gold mineralization and shear zone development were synchronous, and a Pb‐Pb isochron age of 2620 ±6 Ma for pegmatite emplacement either indirectly dates mineralization, or places a minimum age constraint on the timing of mineralization. This age is in accord with a broadly synchronous dominant episode of Archaean lode‐gold mineralization throughout the Yilgarn Block.
Using radar altimetry to update a large-scale hydrological model of the Brahmaputra river basin

Measurements of river and lake water levels from space-borne radar altimeters (past missions include ERS, Envisat, Jason, Topex) are useful for calibration and validation of large-scale hydrological models in poorly gauged river basins. Altimetry data availability over the downstream reaches of the Brahmaputra is excellent (17 high-quality virtual stations from ERS-2, 6 from Topex and 10 from Envisat are available for the Brahmaputra). In this study, altimetry data are used to update a large-scale Budyko-type hydrological model of the Brahmaputra river basin in real time. Altimetry measurements are converted to discharge using rating curves of simulated discharge versus observed altimetry. This approach makes it possible to use altimetry data from river cross sections where both in-situ rating curves and accurate river cross section geometry are not available. Model updating based on radar altimetry improved model performance considerably. The Nash–Sutcliffe model efficiency increased from 0.77 to 0.83. Real-time river basin modelling using radar altimetry has the potential to improve the predictive capability of large-scale hydrological models elsewhere on the planet.
Petrologic and geochemical characterization of the Bullfrog Member of the Crater Flat Tuff: outcrop samples used in waste package experiments

In support of the Waste Package Task within the Nevada Nuclear Waste Storage Investigation (NNWSI), experiments on hydrothermal rock/water interaction, corrosion, thermomechanics, and geochemical modeling calculations are being conducted. All of these activities require characterization of the initial bulk composition, mineralogy, and individual phase geochemistry of the potential repository host rock. This report summarizes the characterization done on samples of the Bullfrog Member of the Crater Flat Tuff (Tcfb) used for Waste Package experimental programs. 11 references, 17 figures, 3 tables.
Investigation of the Mekong River basin hydrology for 1980–2000 using the YHyM

This study investigates the Mekong River basin hydrology for the 1980–2000 period using a grid‐based distributed hydrological model called Yamanashi Hydrological Model (YHyM). The performance of the model is evaluated using data observed at different locations and the results justify the physical soundness of the model. The seasonal variations of climatic and hydrological characteristics of the basin such as soil moisture, ground water saturation deficit, runoff, precipitation, evapotranspiration, etc. are analysed. On the basis of the simulated results, it is noticeable that there is no significant trend in the precipitation, discharge, or soil moisture state of the basin during the simulated period, though there are some seasonal variations which seem to be natural. However the analysis on the precipitation elasticity (E) of the river flow shows that the E values for all sub‐basins are greater than unity, which indicates that x% change in annual precipitation can cause > x% change in annual river flow. Further the basin hydrological responses are analysed for a long term synthetically‐induced drought the results of which show the significance of the base flow of the Mekong River basin. Copyright © 2008 John Wiley & Sons, Ltd.
Interactive effects of basin features and land‐use change on macroinvertebrate communities of headwater streams in the Patagonian Andes

Composition and structure of macroinvertebrate communities were documented in relation to hydrochemical variables over a 10‐month period in four headwater tributaries of the Futaleufú River, northwestern Chubut, Argentina. The streams are located along the strong rainfall gradient that decreases from west to east and they have different basin features. At Blanco and Baggilt streams, riparian vegetation consisted primarily of native Nothofagus forest, while in the Nant y Fall and Rifleros, basins with a long legacy of domestic grazing, the introduced Salix fragilis was the dominant riparian species. Macroinvertebrate species richness, density, and biomass were similar among rivers; however, biomass of shredders was highest in the Nothofagus forested streams and collector‐filterers were significantly higher in Salix fragilis‐bordered rivers. Water temperatures were higher in non‐native Salix sites than in the native or mixed forested sites. Canonical community analysis indicated community composition was related to geomorphic attributes of the rivers, especially slope, basin height (elevation change), distance to the source, substratum size, and Salix coverage. Moreover, seasonally dynamic variables, rainfall and water temperature were good community predictors. Land‐use change (conversion from Nothofagus to pastures and the Salix fragilis invasion in the riverbanks of pasture‐dominated catchments) was interactive with natural stream attributes as determinants of macroinvertebrate distribution and abundance. Copyright © 2004 John Wiley & Sons, Ltd.
Himalayan Cambrian brachiopods

A synoptic analysis of previously published material and new finds reveals that Himalayan Cambrian brachiopods can be referred to 18 genera, of which 17 are considered herein. These contain 20 taxa assigned to species, of which five are new: Eohadrotreta haydeni, Aphelotreta khemangarensis, Hadrotreta timchristiorum, Prototreta? sumnaensis and Amictocracens? brocki. Well‐preserved topotype material from the classic Parahio Valley section is described for three species that have not previously been illustrated photographically. A biostratigraphical scheme based on Cambrian brachiopod occurrence is integrated with that recently proposed for trilobites. Regional correlations based on shared taxa within and across Himalayan lithotectonic belts demonstrate that erosion of Cambrian rocks in the Kurgiakh orogeny in the Parahio Valley removed little of the Parahio Formation and that all of the fossil‐bearing lithotectonic zones share similar late early Cambrian brachiopods, suggesting regional faunal continuity at the time. Palaeobiogeographical analysis of the Cambrian brachiopod faunas from the Himalaya shows that they occupied a marginal position of the Australasian segment of Gondwana.
Depth and geoid anomalies over oceanic hotspot swells: A global survey

The broad depth and geoid anomalies associated with 23 hotspot swells in oceanic areas have been analyzed. Maximum height and geographical extent of the topographic swell, and of the geoid anomaly as well, have been measured for each hotspot. The results indicate a clear increase of the topographic swell height with age of the underlying lithosphere, from values in the range 300-500 m at young ages to values in the range 1,500-2,000 m at ages larger than 100 Ma. The geoid anomaly amplitude also increases with plate age from nearly zero close to mid-ocean ridges, to 6-8 m over old plates. On the other hand, the geographical extent of the swell does not show any clear relationship with plate age. The mean lateral extent of swells range from 1,000 to 1,500 km. Swells located close to spreading ridges show a significant non zero depth anomaly but are associated with negligible geoid signal. These results complete those of a previous study where the apparent compensation depth of oceanic hotspot swells was showed to increase linearly with the square root of plate age and coincide roughly with the base of the thermal lithosphere. This trend may either be interpreted in terms ofmore » lithospheric thinning or dynamical support. Besides both seem necessary to explain the observed bathymetry, in proportion evolving with aging of the lithosphere. « less
A Linear Round Lower Bound for Lovasz-Schrijver SDP Relaxations of Vertex Cover

We study semidefinite programming relaxations of Vertex Cover arising from repeated applications of the LS+ "lift-and-project" method of Lovasz and Schrijver starting from the standard linear programming relaxation. Goemans and Kleinberg prove that after one round of LS+ the integrality gap remains arbitrarily close to 2. Charikar proves an integrality gap of 2, later strengthened by Hatami, Magen, and Markakis, for stronger relaxations that are, however, incomparable with two rounds of LS+. Subsequent work by Georgiou, Magen, Pitassi, and Tourlakis shows that the integrality gap remains 2 -epsiv after Omega (radiclog n-log log n ) rounds [? ]. We prove that the integrality gap remains at least 7/6 - epsiv after cepsivn rounds, where n is the number of vertices and cepsiv > 0 is a constant that depends only on epsiv.
Solubility of TiO 2 in garnet and orthopyroxene: Ti thermometer for ultrahigh-temperature granulites

We report the TiO2 solubility in garnet and orthopyroxene coexisting with rutile calibrated from ex- perimental data at pressures 7-20 kbar and temperatures 850-1300°C in two Antarctic granulite systems. The Ti would substitute for the tetrahedral Si, whereas we could not find positive evidence of the coupled substitution of M-Ti (M is Mg or Fe) for Al-Al in octahedral sites as well as the interstitial substitution of-Ti ( is a vacancy) for M-M in triangular-dodecahedral sites of garnet at ultrahigh-temperature (UHT) metamorphic conditions. The TiO2 content of garnet increases with temperature and decreases with pressure. In orthopyroxene Ti substitutes for atoms in the tetrahedral and octahedral sites. The Ti content of orthopyroxene increases with temperature and increases with pressure. Titanium solubility in garnet and orthopyroxene is not so sensitive to pressure change as compared with temperature dependence given by following empirical equations:
Prediction of 2-D Bed Topography in Rivers

Mathematical models are being developed at the Delft Hydraulics Laboratory for the computation of time-dependent, two-dimensional bed deformation in alluvial rivers. A most promising verification of the predictive capacity of one such model has been obtained for the Waal River in the Netherlands. This model was developed for rivers with dominant bed load transport without significant grain, sorting effects and with approximately constant width. Also, some results of computations with variable boundary conditions are given which simulate the effect of the river regime and the extraction and return of cooling water on the bed topography.
Evolution from an oblique subduction back-arc mobile belt to a highly oblique collisional margin: the Cenozoic tectonic development of Thailand and eastern Myanmar

Abstract Previous tectonic models (escape tectonics, topographic ooze) for SE Asia have considered that Himalayan–Tibetan processes were dominant and imposed on cool, rigid SE Asian crust. However, present-day geothermal gradients, metamorphic mineral assemblages, structural style and igneous intrusions all point to east Myanmar and Thailand having hot, ductile crust during Cenozoic–Recent times. North to NE subduction beneath SE Asia during the Mesozoic–Cenozoic resulted in development of hot, thickened crust in the Thailand–Myanmar region in a back-arc mobile belt setting. This setting changed during the Eocene–Recent to highly oblique collision as India coupled with the west Burma block. The characteristics of the orogenic belt include: (1) a hot and weak former back-arc area about 200–300 km wide (Shan Plateau) heavily intruded by I-type and S-type granites during the Mesozoic and Palaeogene; (2) high modern geothermal gradients (3–7 °C per 100 m) and heat fl ow (70–100 mW m−2; (3) widespread Eocene–Pliocene basaltic volcanism; (4) Late Cretaceous–earliest Cenozoic and Eocene–Oligocene high-temperature–low-pressure metamorphism; (5) c. 47–29 Ma peak metamorphism in the Mogok metamorphic belt followed by c. 30–23 Ma magmatism and exhumation of the belt between the Late Oligocene and early Miocene; (6) a broad zone of Eocene–Oligocene sinistral transpression in the Shan Plateau, later reactivated by Oligocene–Recent dextral transtension; (7) diachronous extensional collapse during the Cenozoic, involving both high-angle normal fault and low-angle normal fault (LANF) bounded basins; (8) progressive collapse of thickened, ductile crust from south (Eocene) to north (Late Oligocene) in the wake of India moving northwards; and (9) the present-day influence on the stress system by both the Himalayan orogenic belt and the Sumatra–Andaman subduction zone.
Hydrologic indicators of hydraulic conditions that drive flow–biota relationships

Abstract This article tests the association between streamflow alteration and the alteration of ecologically significant hydraulic environments. There has been a recent shift in environmental flow assessments to develop rapid desktop-based approaches that are applicable in a regional context. Streamflow statistics (e.g. minimum monthly flow) are often chosen to predict the impact of streamflow alteration on aquatic ecosystems. The assumption that the flow–biota relationship will be obscured by the effect of how streamflow interacts with channel morphology is often acknowledged, but not quantified. In this study, streamflow statistics are derived for 19 reaches in four river systems in Victoria, Australia. Hydraulic metrics were used to quantify ecologically significant surface flow conditions (Froude number) and the area of bench inundation, shallow and deep water. Multivariate analysis was used to investigate the correlation between streamflow statistics altered with regulation and the hydraulic metrics. It was found that streamflow statistics have a weak correlation to surface flow condition and the area of shallow water under natural streamflow conditions. The results show that hydrologic statistics have limited utility in quantifying changes in hydraulic environments. A similar magnitude of flow alteration can produce diverse hydraulic results. The confounding influence of channel morphology prevents streamflow statistics being an adequate surrogate for the assessment of hydraulic alteration. Modelling flow–biota relationships in a regional context is limited by the inadequacy of streamflow statistics to model ecologically significant hydraulic function. Improving knowledge of ecohydraulically significant hydrologic statistics will improve the effectiveness of environmental flow planning to sustain instream habitat conditions. A probabilistic approach is required to enable a risk-based approach to desktop generalization of flow–biota relations. Editor Z.W. Kundzewicz; Guest editor M. Acreman Citation Turner, M. and Stewardson, M. , 2014. Hydrologic indicators of hydraulic conditions that drive flow–biota relationships. Hydrological Sciences Journal, 59 (3–4), 659–672.
Impacts of deforestation and reforestation on soil organic carbon storage and CO2 emission.

Soil organic carbon (SOC) storage and CO2 flux into the atmosphere can be influenced by land use change, especially re/deforestation. The impacts of conversion of primary deciduous (PF) to secondary coniferous (SF) forest and deforestation of PF land to abandoned rangeland (AR) on various soil properties, SOC storage, and soil CO2 emission were investigated on the selected sites (Neshat and Garakpass) in Kelardasht region, northern Iran. The highest SOC storages were determined in coniferous forest land uses (SF1=255.00 and SF2=237.90 Mg C ha − 1 ) followed by deciduous forest (PF1=216.74 and PF2=159.12 Mg C ha −1 ) and abandoned rangeland (AR1=185.31 and AR2=151.60 Mg C ha −1 ). Land use changes showed significant impacts on soil CO2 efflux. The significant positive correlations, with exponential and linear relationships were observed between the monthly CO2 emissions; the minimum air temperature and the cumulative precipitation in the last week ended to CO2 measurement time. The highest recorded soil CO2 efflux in a wide range of land uses were obtained in August to October due to more suitable temperature and rainfall distribution. Based on lower CO2 emission in abandoned rangelands, lesser soil organic carbon is related to lower input to soil. The higher C: N ratios in litter and some of mineral horizons (SF2) and lower CO2 emissions by the higher lignin and polyphenol concentrations (SF1) in coniferous forests compared to deciduous forests have probably caused increasing SOC storage.
Ecosystem carbon storage under different land uses in three semi-arid shrublands and a mesic grassland in South Africa

Carbon (C) storage in biomass and soils is a function of climate, vegetation type, soil type and land management. Carbon storage was examined in intact indigenous vegetation and under different land uses in thicket (250–400 mm mean annual precipitation), xeric shrubland (350 mm), karoo (250 mm), and grassland (900–1200 mm). Carbon storage was as follows: (i) mean soil C (0–50 cm): thicket (T) = grassland (G) > xeric shrubland on Dwyka sediments (XS) > xeric shrubland on dolerite (XSD) > karoo (K) (168, 164, 65, 34 & 26 t ha−1, respectively); (ii) mean root C: T > G > XS = XSD (25.4, 11.4, 7.2 & 7.1 t ha−1); (iii) mean above-ground C including leaf litter: T>XS>G>K> XSD (51.6, 12.9, 2.0, 1.7 & 1.51 ha−1). Carbon stocks in intact indigenous vegetation were related more to woodiness of vegetation and frequency of fire than to climate. Biomass C was greatest in woody thicket and soil C stocks were greatest in thicket and grassland. Total C storage of 245 t ha−9 in thicket is exceptionally high for a semi-arid region and is comparable with mesic forests. Soil C dominated ecosystem C storage in grassland and was influenced more by soil parent material than land use. The semi-arid sites (xeric shrubland and thicket) were more sensitive to effects of land use on C storage than the grassland site. Effects of land use on C stocks were site- and land use-specific and defied prediction in many instances. The results suggest that modelling of national C stocks would benefit from further research on the interactions between C storage, land use, and soil properties.
The graptolitic age of the type Ashgill Series (Ordovician), Cumbria, UK

SUMMARY The Rawtheyan Stage of the type Ashgill Series, in Westerdale, Cumbria, is shown to be of linearis Biozone age, largely on the basis of extensive new graptolite collections. This is the only reliable graptolite dating of the type Ashgill, although it is possible that the underlying Cautleyan Stage is also of linearis Biozone age. There is no direct evidence for the complanatus, anceps, extraordinarius and persculptus biozones, although these could equate roughly with the top of Ingham’s (1966) zone 7 and his zone 8, the latter embracing the Ashgill (Shales) Formation. A total of 26 graptolite taxa have been identified in the type Ashgill Series, from 26 localities, many of them new. Dicellograptus praeanceps sp. nov. is described.