Miracle-dz/UniFAR-FTUs huggingface dataset:
Carbonatites and lamprophyres of the Gardar Province – a 'window' to the sub-Gardar mantle ?

Abstract Carbonatite magmas are considered to be ultimately derived from mantle sources, which may include lithospheric and asthenospheric reservoirs. Isotopic studies of carbonatite magmatism around the globe have typically suggested that more than one source needs to be invoked for generation of the parental melts to carbonatites, often involving the interaction of asthenosphere and lithosphere. In the rift-related, Proterozoic Gardar Igneous Province of SW Greenland, carbonatite occurs as dykes within the Igaliko Nepheline Syenite Complex, as eruptive rocks and diatremes at Qassiarsuk, as a late plug associated with nepheline syenite at Grønnedal-Íka, and as small bodies associated with ultramafic lamprophyre dykes. The well-known cryolite deposit at Ivittuut was also rich in magmatic carbonate. The carbonatites are derived from the mantle with relatively little crustal contamination, and therefore should provide important information about the mantle sources of Gardar magmas. In particular, they |are found intruded both into Archaean and Proterozoic crust, and hence provide a test for the involvement of lithospheric mantle. A synthesis of new and previously published major and trace element, Sr, Nd, C and O isotope data for carbonatites and associated lamprophyres from the Gardar Province is presented. The majority of Gardar carbonatites and lamprophyres have consistent geochemical and isotopic signatures that are similar to those typically found in ocean island basalts. The geochemical characteristics of the two suites of magmas are similar enough to suggest that they were derived from the same mantle source. C and O isotope data are also consistent with a mantle derivation for the carbonatite magmas, and support the theory of a cogenetic origin for the carbonatites and the lamprophyres. The differences between the carbonatites and lamprophyres are considered to represent differing degrees of partial melting of a similar source. We suggest that the ultimate source of these magmas is the asthenospheric mantle, since there is no geochemical or isotopic evidence for their having been derived directly from ancient, enriched sub-continental lithospheric mantle. However, it is likely that the magmas actually formed through a two-stage process, with small-degree volatile-rich partial melts rising from the asthenospheric mantle and being ‘frozen in’ as metasomites, which were then rapidly remobilized during Gardar rifting.
Tidal and atmospheric forcing of the upper ocean in the Gulf of California: 1. Sea surface temperature variability

Two years of satellite infrared imagery (1984–1986) are used to examine the sea surface temperature (SST) variability in the northern Gulf of California. Empirical orthogonal functions (EOFs) of the temporal and spatial SST variance for 20 monthly mean images show that the dominant SST patterns are generated by spatially varying tidal mixing in the presence of seasonal heating and cooling. These patterns are modified in the fall and winter when shelf temperatures south of Tiburon Island cool in response to upwelling-favorable winds. These same winds bring cold, dry air from off the continental United States, causing local cooling of the shallow northern shelf. During the rest of the year, the broad, shallow shelves are warmer than offshore. The seasonally reversing temperature patterns are consistent with recent hydrographic observations which show a cyclonic surface circulation in the summer and a weaker anticyclonic circulation during the rest of the year. Atmospheric forcing of the northern gulf appears to occur over large spatial scales. Area-averaged SSTs for the Guaymas Basin, island region, and northern basin show significant fluctuations which are highly correlated. These fluctuations in SST correspond to similar fluctuations in the air temperature which are related to synoptic weather events over the gulf. During periods of particularly low wind speeds, the air temperature over the gulf increases dramatically. By afternoon, intense heating of the sea surface results in the appearance of warm SST anomalies in the satellite data. These SSTs are approximately 2°C warmer than surrounding SSTs and most likely occur as a result of a spatially varying wind field. A regression analysis of the SST relative to the fortnightly tidal range shows that tidal mixing occurs over the sills in the island region as well as on the shallow norther shelf. Mixing over the sills, however, occurs as a result of large breaking internal waves or internal hydraulic jumps which mix water over the upper 300–500 m. This mixing pumps heat away from the surface, deep into the water column, there by maintaining the cool SSTs. Since mixing occurs over greater depths in the island region, the temperatures there are much colder than those generated by tidal mixing on the shallow shelves, resulting in the persistent pool of cool water evident in the satellite data. This cooler water is mixed horizontally by the basin-scale circulation, lowering the SSTs over much of the northern gulf. These reduced SSTs have a large impact on the surface heat flux by lowering the saturation vapor pressure of the air. As a result, the amount of heat lost to the atmosphere through the latent or evaporative heat flux is reduced. This may explain why the Gulf of California gains heat on an annual average rather than losing heat as occurs in the Mediterranean and Red seas where tidal mixing is not significant.
Atmospheric General Circulation Simulations with the BMRC Global Spectral Model. The Impact of Revised Physical Parameterizations

Abstract Results are presented for perpetual January and July general circulation simulations using the Australian Bureau of Meteorology Research Centre global spectral model. Particular emphasis is placed on the impact of changes in the physical parameterizations and horizontal resolution on the modeled fields. The results include variances and eddy transports as well as zonal means and geographical distributions. Of the experiments conducted the most satisfactory results were obtained using stability-dependent vertical diffusion and a combination of the Kuo scheme for deep convection and the Tiedtke shallow convection scheme. The simulation of the polar night region of the stratosphere in January was much more realistic than in results obtained using an earlier version of the model. The improvement is attributed to the revised radiation code, supporting the conclusions of Ramanathan et al. on the sensitivity of simulations of this region of the atmosphere to the treatment of radiative processes.
Estimation of Nonpoint Source Nitrate Concentrations in Indiana Rivers Based on Agricultural Drainage in the Watershed

Subsurface tile‐drained agricultural fields are known to be important contributors to nitrate in surface water in the Midwest, but the effect of these fields on nitrate at the watershed scale is difficult to quantify. Data for 25 watersheds monitored by the Indiana Department of Environmental Management and located near a U.S. Geological Survey stream gage were used to investigate the relationship between flow‐weighted mean concentration (FWMC) of nitrate‐N and the subsurface tile‐drained area (DA) of the watershed. The tile DA was estimated from soil drainage class, land use, and slope. Nitrate loads from point sources were estimated based on reported flows of major permitted facilities with mean nitrate‐N concentrations from published sources. Linear regression models exhibited a statistically significant relationship between annual/monthly nonpoint source (NPS) nitrate‐N and DA percentage. The annual model explained 71% of the variation in FWMC of nitrate‐N. The annual and monthly models were tested in 10 additional watersheds, most with absolute errors within 1 mg/l in the predicted FWMC. These models can be used to estimate NPS nitrate for unmonitored watersheds in similar areas, especially for drained agricultural areas where model performance was strongest, and to predict the nitrate reduction when various tile drainage management techniques are employed.
Enhancement in the productivity of maize (Zea mays L) through integrated balanced nutrient management in Banswara district

The rabi maize productivity is low in Banswara district of Rajasthan. Farmer's of the Banswara district are not completely following the package and practices viz., fertilizer management in rabi maize. To convince the farmer's of the area about the use of balanced nutrition to crops, on farm testing at farmer's field of integrated nutrient management on the productivity of maize was conducted for two consecutive years 2007-08 and 2008-09 in village Jantoda and Khandadera. The grain yield was increased with the tune of more than 50 per cent with the application of integrated nutrient over the existing farmer's practice of nutrient management. The B:C ratio of INM was found higher (1.32) as compared to farmer's practice of nutrient management (1.01).
Oxygen diffusion in San Carlos olivine

The self-diffusion of oxygen in San Carlos olivine single crystals has been measured along the [001] direction. The diffusion experiments were performed using a gas mixture Ar + H2/Ar + H218O flowing around the olivine specimens. This gas mixture acts as the isotopic reservoir and is also used to establish and adjust the desired oxygen fugacity, allowing us to determine the oxygen diffusion coefficient D as a function of pO2. Thirty runs have been performed at 1 atm total pressure within the (T,pO2) olivine stability field, T ranging from 1363 to 1773 K and pO2 from 7×10−7 to 5×10−2 Pa. The annealing duration t was chosen such that the characteristic isotope penetration depth 2Dt ranges between 600 and 11,000A. The diffusion profiles of 18O were determined using the 18O(p, α)15N nuclear microanalysis technique. The diffusion coefficient can be written D* = D0* exp(−E/RT)(pO2/p0)m, where E is the activation energy, R is the gas constant, T is the temperature in K, pO2 is the oxygen partial pressure, p0 is the room pressure, m is a numerical coefficient, and D0* is the preexponential term. A data inversion method has been used to determine the three parameters and yields log(D0*) = −5.2(±3.6) with D0* in m2/s, E = 318(±17) kJ/mol, m = 0.34(±0.02); D* = 6.7 × 10−6exp(−38,000/T)(pO2/p0)0.34 m2/s; the number in parentheses is the standard deviation. D* is related to the self-diffusion coefficient D by the relation D* = ƒD, with ƒ close to 1.0. An attempt to show pipe diffusion in predeformed samples, with a dislocation density of about 2×1011 m−2, along dislocation cores perpendicular to the specimen surface, showed no contribution to the main bulk diffusion. We conclude that in olivine, Fo≃90, within the temperature range investigated, DFe, DMg ≫ D0x ≫ DSi as has already been demonstrated in FO100. E is of the same order of magnitude as the Si - O bond energy and as E in Fo100. We infer that the oxygen diffusion occurs via an interstitial mode and that these defects carry one negative charge. This interstitial mechanism is rather surprising in view of the compact oxygen sublattice of olivine. However, interstitial transport of oxygen has already been identified in other oxygen compact compounds.
Finite volume simulations of dynamos in ellipsoidal planets

It is widely accepted, that the planetary magnetic ﬁelds are powered by a magnetohydrodynamic dynamo-process. So far theoretical studies and numerical simulations have mostly assumed that the ﬂow generating the dynamo-process is driven by buoyancy forces. But also precession can drive a dynamo, as ﬁrst suggested by Bullard in 1949. A precession-driven laminar ﬂow is mainly toroidal and cannot maintain a dynamo. However, experimental and numerical studies show that these basic ﬂows are unstable and several kind of wave-like instabilities are generated. Therefore precession can also be regarded as a viable driving-mechanism of a core ﬂow generating the planetary magnetic ﬁelds. We have used a spherical, ﬁnite-volume code, already used for the simulation of convection-driven dynamos and mantle convection, to solve the equations of a precession-driven dynamo in a spherical shell. Furthermore the non-sphericity of the planetary bodies trigger some crucial instabilities. However, up to now there is only one available full MHD study of precessing spheroids. These preliminary results for a full spheroid showed that topographic coupling offers more favourable conditions than viscous coupling for the generation of a sizeable dipole component of the magnetic ﬁeld. We shall discuss how the ellipticity of the planets can be included in numerical simulations by the use of a non-orthogonal grid. We will present some ﬁrst results of MHD calculations with parameters similar to known dynamo solutions but with no-slip instead of stress-free boundary conditions to clarify the inﬂuence of boundary layers on the dynamo process.
Optimising drought adaptation by small-scale farmers in southern Africa through integration of indigenous and technologically-driven practices

This paper reviews and synthesises research-based literature on drought adaptation practices among small-scale farmers in southern Africa. The paper reviews the existing literature in order to identify ways in which small-scale poor farmers in southern Africa adapt to the effects of drought. The paper further presents some constraints that limit small-scale farmers from adopting technologically-driven drought adaptation practices. The main message of this paper is that neither indigenous nor technologically-driven practices should be seen as panacea on their own, but integrating the two sets of practices could optimise adaptation by small-scale farmers. The material presented in this paper could be helpful to researchers, development planners and policy makers in their quest towards finding means of enhancing drought adaptation practices by small-scale farmers.
Effect of quartz inclusions on plastic flow in marble

To investigate the effect of variations in volume fraction of a second phase on the strength and microstructure of rocks, we produced synthetic marbles with a grainsize of 5–25 µm, containing quartz of similar size, with volume fractions of 0, 5.1, and 20.4 vol.%, and between 3 to 9% porosity. These rocks were deformed in triaxial compression at a strain‐rate of 3 × 10−5 s−1 confining pressure of 200 MPa, and 600°C. Marbles containing 20.4 vol.% quartz were almost 5 times stronger than those containing no quartz. The work‐hardening rate at given strain increased with quartz content. Marbles containing 20.4 vol.% quartz work‐hardened up to 10% strain whereas in single‐phase samples work hardening was negligible beyond 3% strain. The dislocation density in the calcite increased with increasing quartz content. The data are consistent with models for the strength of ceramic matrix composites, or with the hypothesis that strength is increased by decreasing porosity.
Crossbreeding of sheep under semi-arid conditions

Data were obtained on 3028 lambs born during five successive years from 1961 to 1966 at Ras El-Hekma Desert Research Station in the Western Coastal Egyptian Desert. Breed groups involved in the study were Hungarian Merino, Syrian Awassi, native Barki sheep, and nine of their crosses. The characters studied were birth weight, weaning and yearling weights, pre- and post-weaning average daily gain and yearling greasy fleece weight. The effects of breed group, year of birth, sex, age of dam and type of birth on these characters were investigated. The results obtained showed that Barki lambs excelled Merino lambs in all the traits related to body growth. Merino lambs, on the other hand, excelled Barkis in fleece weight. Barki lambs also excelled Awassi lambs in all traits except birth and weaning weights. In all characters except pre-weaning gain, the first cross of Merino and Barki (½M½B) was markedly superior to all the other crosses and pure breeds. The two third-crosses, ⅜ M ⅝ B and ⅝ M ⅜ B, were similar to each other in their productive traits and were slightly inferior to the first cross. The two back-crosses, ¼M¾B and ¾M¼B, were markedly different from each other, the former being better than the latter. The three-eighths Merino group is suggested for developing a new strain of sheep for the semi-arid regions. The effects of the environmental factors on the six characters studied were all highly significant except for the effect of sex on fleece weight and the effects of age of dam and type of birth on growth from weaning to yearling ages. The most important factor affecting the different traits was year of birth. Type of birth and age of dam were important sources of variation only for the characters studied till weaning age, but became of little importance thereafter. The effect of sex was pronounced only on yearling weight.
FAULT DISPLACEMENTS AND MOTION RELATED TO NUCLEAR EXPLOSIONS.

abstract Studies of some of the geologic effects of underground nuclear explosions that have been carried on during the last 3 years by the U. S. Geological Survey on behalf of the U. S. Atomic Energy Commission are summarized. Movement has been triggered on some faults within a few thousand feet of explosions in Nevada and in Amchitka Island, Alaska. The permanent relative vertical displacement on the faults always has been in the same direction as the last recognizable natural tectonic displacement and has been as much as 1 m (meter); horizontal displacement of as much as 15 cm (centimeters) has occurred on a few faults although no previous horizontal displacement had been apparent. The strike length of triggered faulting ranges from about 1 to 8 km (kilometers) and seems to correlate linearly with yield and magnitude of the explosions. High-speed motion picture photography of two faults from both the air and the ground provides the following data on the motion of the faults. 1 Fault motion started at the first arrival of seismic energy. 2 Rupture velocity along triggered faults, measured over a distance of 0.210 km, was 2.1 km/sec (kilometers per second) in alluvium of Hot Creek Valley, Nevada, which has a compressional velocity that ranges from about 2 km/sec to 3.3 km/sec and which has a density of 2.3 g/cc. 3 The velocity of displacement of alluvium at the Yucca Fault plane in Yucca Flat was a little more than 1 m/sec (meters per second). Velocity of displacement of alluvium at the fault plane in Hot Creek Valley was between 6 and 30 m/sec.
Effects of increased horizontal resolution in a simulation of the North Atlantic Ocean

Global mean and eddy fields from a four-year experiment with a 1/6° × 1/5° horizontal resolution implementation of the CME North Atlantic model are presented. The time-averaged wind-driven and thermohaline circulation in the model is compared to the results of a 1/3° × 2/5° model run in very similar configuration. In general, the higher resolution results are found to confirm that the resolution of previous CME experiments is sufficient to describe many features of the large-scale circulation and water mass distribution quite well. While the increased resolution does not lead to large changes in the mean flow patterns, the variability in the model is enhanced significantly. On the other hand, however, not all aspects of the circulation have improved with resolution. The Azores Current Frontal Zone with its variability in the eastern basin is still represented very poorly. Particular attention is also directed toward the unrealistic stationary anticyclones north of Cape Hatteras and in the Gulf of Mexico.
Relative geomagnetic field intensity and reversals for the last 1.8 My from a central equatorial Pacific Core

We have made a new analysis of core KK78O30 from the central equatorial Pacific. This core has recorded the last 4 reversals. Mineral-magnetic analysis establishes that these sediments meet the current criteria for reliable relative paleointensity determinations. Normalisation with ARM, IRM and χ yields very similar results. There is no evidence for a “saw-tooth” pattern such as the one obtained by Valet and Meynadier [1993] and Meynadier et al. [1994] for the last 4 million years. Rather, the average field intensity record appears to display more or less symmetric peaks and troughs, superposed to a broad high between reversals.
The Relationship between Site Characteristics and Pinus radiata Growth on the Tsitsikamma Plateau, South Africa

SYNOPSIS A site-growth study using a range of data from 46 plots on the Tsitsikamma plateau was undertaken for modelling the growth of Pinus radiata. Growth models for the prediction of site index at a reference age are imperative in an area with complex soil patterns such as occur on the Tsitsikamma plateau. The proposed model used three soil physical and three soil chemical parameters, explaining 77% of the variation in S120, which is relatively high for site-growth studies of this kind. Effective soil depth and available phosphate were found to be most significant site factors. The strategy of modelling on a landtype basis appears to be responsible for the good correlations that were found.
Modulus and damping equations of sands subjected to combined dynamic loadings

Abstract Dynamic loading due to earthquakes is made up of combinations of different wave types, including compressive waves, shear waves, etc. It has been shown that if a soil specimen is subjected to a combined longitudinal and torsional sinusoidal loading, significant degradation of the specimen occurs wherein the modulus is reduced and the damping increased more than for a single excitation. The use of dynamic properties obtained from such combined loadings are more representative of actual field conditions than those from single-loading conditions. Testing sands subjected to random and impulse types of combined loading demonstrates that octahedral shear strain is a useful parameter for describing the effects of combined loading as in the case of sinusoidal loading. The paper presents equations for the determination of the shear modulus, Young's modulus, and damping of sandy soils subjected to these combined loadings. From the equations, the degree of specimen degradation can be determined, as well as the threshold strain ratio needed for the degradation to occur.
The long–term survival of bone: the role of bioerosion

Fossil bones (N = 350) spanning more than 350 million years, and covering a wide range of depositional environments, were studied to compare the distribution of microbial destruction features in fossil bones with previously published data sets of bones of archaeological age. The distribution of bioerosion in fossil bones is very different from that found in bone from archaeological sites. Fossil bones typically show little or no bioerosion. Under normal conditions, if a bone is to survive into the fossil record, then rapid bioerosion must be prevented (or halted). This conclusion suggests that early post mortem processes,such as the mode of death, influence the potential of any bone to survive into deep time.
Estimation of Surface Turbulent Fluxes through Assimilation of Radiometric Surface Temperature Sequences

Abstract A model of land surface energy balance is used as a constraint on the estimation of factors characterizing land surface influences on evaporation and turbulent heat transfer from sequences of radiometric surface temperature measurements. The surface moisture control on evaporation is captured by the dimensionless evaporative fraction (ratio of latent heat flux to the sum of the turbulent fluxes), which is nearly constant for near-peak radiation hours on days without precipitation. The dimensionless parameter capturing the turbulent transfer characteristics (bulk heat transfer coefficient) includes the impacts of both forced and free convection. The mean diurnal pattern and seasonal trends are interpreted in the context of expected surface air layer static stability variations. The approach is tested over the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) site (Kansas) where verification data on surface fluxes are available. It is shown that sequent.