Miracle-dz/UniFAR-FTUs huggingface dataset:
Cyclicity in the Main and Upper Zones of the Bushveld Complex, South Africa: Crystallization from a Zoned Magma Sheet

The major element composition of plagioclase, pyroxene, olivine, and magnetite, and whole-rock Sr/Sr data are presented for the uppermost 2.1 km of the layered mafic rocks (upper Main Zone and Upper Zone) at Bierkraal in the western Bushveld Complex. Initial Sr/Sr ratios are near-constant (0.7073 ± 0.0001) for 24 samples and imply crystallization from a homogeneous magma sheet without major magma recharge or assimilation. The 2125 m thick section investigated in drill core comprises 26 magnetitite and six nelsonite (magnetite–ilmenite–apatite) layers and changes up-section from gabbronorite (An72 plagioclase; Mg# 74 clinopyroxene) to magnetite–ilmenite–apatite–fayalite ferrodiorite (An43; Mg# 5 clinopyroxene; Fo1 olivine). The overall fractionation trend is, however, interrupted by reversals characterized by higher An% of plagioclase, higher Mg# of pyroxene and olivine, and higher V2O5 of magnetite. In the upper half of the succession there is also the intermittent presence of cumulus olivine and apatite. These reversals in normal fractionation trends define the bases of at least nine major cycles. We have calculated a plausible composition for the magma from which this entire succession formed. Forward fractional crystallization modeling of this composition predicts an initial increase in total iron, near-constant SiO2 and an increasing density of the residual magma before magnetite crystallizes. After magnetite begins to crystallize the residual magma shows a nearconstant total iron, an increase in SiO2 and decrease in density. We explain the observed cyclicity by bottom crystallization. Initially magma stratification developed during crystallization of the basal gabbronorites. Once magnetite began to crystallize, periodic density inversion led to mixing with the overlying magma layer, producing mineralogical breaks between fractionation cycles. The magnetitite and nelsonite layers mainly occur within fractionation cycles, not at their bases. In at least two cases, crystallization of thick magnetitite layers may have lowered the density of the basal layer of melt dramatically, and triggered the proposed density inversion, resulting in close, but not perfect, coincidence of mineralogical breaks and packages of magnetitite layers.
EFECTO DEL ANÁLOGO DE BRASINOESTEROIDES BIOBRAS 6 EN EL RENDIMIENTO Y OTROS CARACTERES EN EL CULTIVO DEL ARROZ (Oryza sativa L.)

The experimental work was developed in areas of «Los Palacios» Rice Research Station, belonging to the National Institute of Agricultural Sciences, with the objective of studying the influence of a brassinosteroid analogue synthesized in Cuba, commercially known as BIOBRAS 6, on rice yield and other variables. In the experiment six treatments were studied, the variety INCA LP-2 was used. The character number of panicle/m 2 was the component that most influenced yield response. In general, and taking into account the results of the work, the efficiency of BB 6 can be confirmed as stimulant of agricultural yield in rice crop. Results showed that the total dose of 50 mg.ha -1 was the most effective in both sowing seasons, the phases of active tillering and early stage of heading, in winter, and early stage of heading and filled of grain, in spring, being the best responses.
On the flow of polythermal glaciers - I. Model and preliminary analysis

Many interesting phenomena have been observed in the flow of glacial ice masses. In order to establish a rational theory for the study of these phenomena, we develop here a detailed continuum model for the flow of polythermal (i. e. partially cold and partially temperate) glaciers in wide mountain valleys. As a first step in the analysis of the nonlinear double free boundary problem posed by this model, the structure and stability of solutions are studied in a particular very simple limiting situation. Further analysis is deferred to part II of the paper.
The horse in late Pleistocene and Holocene Britain

Until now, the horse was one of the few members of the British Late Pleistocene and Holocene fauna which had yet to be fully investigated. In this thesis, chronological, palaeoecological and morphological data based on direct investigations of British and European fossil and sub-fossil horses are presented. The time-frame encompasses the latest certain wild horses in Britain and continental Europe through to the early diversification of domestic types, and thus spans the interval from c. 15,000-2,000 years before present (BP). The gazetteers presented are the result of a thorough survey and intensive study of all relevant British (as well as selected continental) collections of fossil and sub-fossil horse material. Furthermore, the incorporation into this project of a radiocarbon accelerator dating programme has provided 45 new, direct horse dates from 31 British/Irish sites. A systematic review of all new and previously obtained dates reveals a complex pattern of chronological and geographical distribution for horses during the study interval. These data are interpreted with reference to known climatic and environmental events which are detailed. Further investigations are presented which reveal the ecological reactions of wild horses to underlying environmental factors such as climate change and vegetational succession. Questions of body size variability as well as taxonomic and relationship issues are addressed by means of a detailed morphological investigation. Cranial and postcranial measurements are employed to expose variation and diversification of size and form among wild and domestic animals of three key periods: Mid-Devensian, Late Glacial/early Post Glacial, middle to later Post Glacial. In addition, body size comparisons are made between British and continental horses for each episode. Finally, there is discussion of alternative ways of revealing relationships between ancient and modern horses. In particular, molecular evidence is reviewed with the aim of assessing its value to taxonomic, morphological and chronological studies
Spatial distribution of ionization in the equatorial and low‐latitude ionosphere of the Indian sector and its effect on the pierce point altitude for GPS applications during low solar activity periods

[1] The equatorial and low-latitude ionosphere is characterized by dynamic changes in the spatial distribution of F region electron density. The in situ density data from Indian SROSS C2 satellite was used in conjunction with the international reference ionosphere (IRI) to demonstrate how the median models have limitations to represent the spatial gradients in the equatorial and subtropical latitudes in the Indian sector. The ground-based ionosonde data was used to derive the bottomside electron density profiles which were matched with IRI to derive the complete F region electron density profile for different times to show the variability in the centroid of ionization mass distribution due to the equatorial plasma dynamics associated with Appleton ionization anomaly. The study brings out that a uniform ionospheric pierce point altitude cannot be assumed for GPS applications in this sector. However, during low sunspot activity periods, the GPS-derived total electron content (TEC) using 2 × 2 grid point data indicates that spatial gradients in TEC are not too significant in meridian transects and that the assumption of homogeneous distribution is valid for the conversion of slant to vertical TEC even in the equatorial latitudes during solar minimum. Keeping this in view, a qualitative study has been carried out on the possible variability in ionospheric pierce point altitude at representative subtropical latitude in the Indian sector and the results are discussed in light of diurnal and seasonal features of the equatorial ionosphere.
Chemical zoning of muscovite from the Ervedosa granite, northern Portugal

Abstract The tin-bearing muscovite granite from Ervedosa contains unzoned primary muscovite. This Hercynian S-type granite was hydrothermally altered at the stanniferous quartz vein walls and contains three types of muscovite: (1) very small unzoned muscovite replacing albite; (2) small unzoned hydrothermal muscovite replacing K-feldspar and quartz; and (3) zoned subhedral muscovite. In the zoned muscovite, the core has a composition similar to that of magmatic muscovite from the unaltered granite, while the rim has a composition similar to that of hydrothermal muscovite replacing K-feldspar and quartz in the altered granite. The rim corresponds to a late overgrowth richer in the celadonitic component than the core. Infiltrated mineralizing fluids reacted with biotite and K-feldspar of the unaltered granite. We interpret the rim of muscovite to have precipitated from these solutions.
Initial impact of the Gabčíkovo hydroelectric scheme on the species richness and composition of 0+ fish assemblages in the Slovak flood plain, River Danube

Relatively little information exists on the effects of hydroelectric schemes on 0+ fish composition in large European rivers because few or no pre‐impact data exist. We compared 0+ fish species richness and composition, relative density, fish size as well as available and used habitat using data from 12 floodplain sites sampled just prior to (1992) and four years after (1996) the start of operations of the Gabčíkovo hydropower station on the River Danube (Slovakia). We also used modelling techniques to assess the change in species richness and habitat use and to predict 1996 occurrences from the 1992 data set. The floodplain was greatly modified by the hydroscheme. Only 12 of 27 sites sampled in August 1992 were extant in August 1996. Therefore, all four channel types identified (flowing, abandoned, weir, wing‐dam) were more lentic in 1996 than in 1992, with increased width, smaller‐sized sediment (silt, clay) and greater amounts of macrophytes. After the operations of the hydroscheme, the overall relative density of fishes (individuals per surface area) of all ages decreased, with the exception of 0+ fishes, despite a slight reduction in 0+ fish density in all channel types except weirs. Species number increased from 25 to 28, although in all channel types there was a change in the composition of the 0+ fish assemblages, with rheophiles generally replaced by limnophiles and migrants from the lower Danube. The two most important microhabitat variables were the proportion of macrophytes and gravel, the latter being the factor distinguishing 0+ fish microhabitat use in 1992 (preferences) and 1996 (indifference or avoidance). Species richness and 0+ fish density in 1996 could be predicted from the 1992 data using simple log‐linear models (density, richness, sample number). Species‐specific occurrence in 1996 could not be predicted using environmental/fish data from 1992 with multiple regression or generalized additive models (GAM). However, the overall GAM from 1992 could predict overall fish occurrence in 1996. Copyright © 2003 John Wiley & Sons, Ltd.
Water, land and health in urban and peri‐urban food production: the case of Kano, Nigeria

In sub‐Saharan Africa, urban and peri‐urban food production has been identified as an important resource for meeting the challenges of rapidly growing cities, and the positive aspects of such production have been well documented in the literature. This paper examines some of the health and environmental concerns associated with urban and peri‐urban agriculture (UPA). Empirical evidence from the city of Kano in northern Nigeria suggests that there is currently much reason for concern as industrial and domestic toxins are reaching dangerously high levels. As soils and water channels become increasingly polluted, the sustainability of urban and peri‐urban food production is questioned. Since the health implications of long‐term exposure to toxins are unclear, it is suggested that coordinated longitudinal research involving urban planners, agricultural scientists and health specialists is urgently needed. In addition, it remains crucial that government and institutional actors effectively monitor and enforce both environmental and zoning by‐laws, if the health and environmental constraints of UPA are to be overcome, and the future sustainability of production is to be assured. Copyright © 2003 John Wiley & Sons, Ltd.
Heavy Metals in Sediments of the Gold Mining Impacted Pra River Basin, Ghana, West Africa

Total concentrations of Hg, Al, Fe, As, Pb, Cu, Cr, Ni, Mn, Co, V, and Zn were determined in surface sediments collected from 21 locations within the gold mining impacted Pra River basin in southwestern Ghana. Samples were collected during both the rainy and dry seasons. We hypothesized that in the rural southwestern portion of Ghana, the lack of industrial activities makes artisanal gold mining (AGM) by Hg amalgamation the main source of water resource contamination with heavy metals. Therefore, metals showing concentration trends similar to that of Hg in the studied system are likely impacted by AGM. We found that total-Hg (THg) concentrations in riverine sediments are rather low as compared to other aquatic systems that are impacted by similar mining activities. Measured THg concentrations ranged from 0.018 to 2.917 mg/kg in samples collected in the rainy season and from about 0.01 to 0.043 mg/kg in those collected during the dry season. However, the determination of the enrichment factor (EF) calculated using shale data as reference background values showed signs of severe contamination in most of the sampled sites. In the dry season, THg concentrations correlated positively and significantly to the concentrations of As (r = 0.864, p < 0.01), Cu (r = 0.691, p < 0.05), and Ni (r = 0.579, p < 0.05). Based on our previously stated hypothesis, this could then be an indication of the impact of AGM on ambient levels of these 3 elements. However, the determined concentrations of Cu, and Ni co-varied significantly with Al, suggesting that natural sources do account for the observed levels. Accordingly, both AGM and metal inputs from weathered natural deposits are likely co-responsible for the observed levels of Cu and Ni. In contrast, the lack of correlation between As and Al tends to suggest an impact of AGM on As levels. Overall, our data suggest that besides Hg and to some extent As, the impact of AGM on ambient levels of investigated metals in the gold mining impacted Pra River remains negligible. Finally, the increase in metal concentrations from the dry to the rainy season underlines the impact of changes in hydrologic conditions on levels and fate of metals in this tropical aquatic system.
TRAVERTINOS Y JASPEROIDES DE MANANTIAL ESPEJO, UN AMBIENTE HOT SPRING JURASICO. MACIZO DEL DESEADO, PROVINCIA DE SANTA CRUZ, ARGENTINA

Resumen: En este trabajo se analiza el origen y las relaciones entre travertinos y jasperoides intercalados en rocas volcaniclasticas jurasicas en el distrito argento-aurifero Manantial Espejo, ubicado en el borde sur-occidental del Macizo del Deseado, provincia de Santa Cruz, Argentina. Los cuerpos de travertino constituyen estratos delgados de hasta 60 cm de espesor de calcita micritica finamente laminada, en ocasiones con estratificacion ritmica de calcita y opalo, asociados a depositos de tobas de caida y tufitas de ambiente lacustre. En algunos afloramientos los morfotipos reconocidos revelan que la precipitacion del carbonato correspondia a sectores proximales relacionados a geysers y conductos de vapor, los cuales se orientaban a los largo de las fracturas que constituyeron los canales de circulacion de fluidos. La posterior silicificacion de los niveles carbonaticos produjeron jasperoides que se presentan como cuerpos tabulares subverticales y subhorizontales, estos ultimos con caracteristicas texturales similares a aquellas de sinters. La silicificacion se origino tardiamente, posiblemente durante la etapa principal del regimen hidrotermal que genero las vetas portadoras de plata y oro. Los travertinos se formaron en un ambiente de hot spring, relacionado con fracturas de un sistema de cizalla conjugado orientadas entre N 20° a 45° E y N 20° a 40° O y constituyen las evidencias mas tempranas de la presencia de un regimen epitermal asociado al proceso volcanico jurasico, en un regimen tectonico distensivo, en Manantial Espejo.
Determining input values for a simple parametric model to estimate evaporation from vineyard soils with special reference to clay content and trellis system

Estimating soil evaporation (Es) is an important part of modelling vineyard evapotranspiration for irrigation purposes. Furthermore, quantification of possible soil texture and trellis effects is essential. Daily Es from six topsoils packed into lysimeters was measured under grapevines on slanting and vertical trellises, respectively. Following irrigation, cumulative soil evaporation (ΣEs) from the bare, untilled soils over 14-day drying cycles was plotted against cumulative reference evapotranspiration (ΣETo) to determine Es transition from the constant rate stage (Stage 1) to the falling-rate stage (Stage 2). During Stages 1 and 2, rate of Es is determined by atmospheric conditions and soil properties, respectively. Slopes of ΣEs vs square root of ΣETo plots in Stage 2 provided the input constant (β value) for each soil. In Stage 1, ΣEs was almost equal to ΣETo but the ratio varied as grapevine canopies developed. The β values varied between 2.15 ± 0.09 mm0.5 and 4.68 ± 0.14 mm0.5. The β values were best related to clay content (R2 was 0.7861 and 0.5108 for horizontal and vertical canopies, respectively). The vertical trellis seemed to have a windbreak effect that tended to reduce Es compared to the slanting trellis. Therefore, clay content and trellis orientation effects on β need to be considered.
Effects of Oil on Foam Generation and Propagation in Sandstone Porous Media

Foaming of nitrogen stabilized by C14-16 alpha olefin sulfonate in natural sandstone porous media, previously subject to water flooding, was studied experimentally. Foam was generated in-situ by co-injecting gas and surfactant solution at fixed foam quality. Effect of surfactant concentration on the foam strength and foam propagation was examined. X-ray CT scans were obtained to visualize the foam displacement process and to determine fluid saturation at different times. The experiments revealed that stable foam could be obtained in the presence of water-flood residual oil. CT scan images, fluid saturation profiles and mobility reduction factors demonstrated that foam exhibited a good mobility control in the presence of water-flood residual oil. This was further confirmed by a delay in the gas breakthrough. The experiments also proved that immiscible foam displaced additional oil from water-flooded sandstone cores, supporting the idea that foam is potentially an effective EOR method. Foam flooding provided an incremental oil recovery ranging from 13±0.5% of the oil initially in place for 0.1 wt% foam to 29±2% for 1.0 wt% foam. Incremental oil due to foam flow was obtained first by a formation of an oil bank and then by a long tail production due to transport of dispersed oil within the flowing foam. The oil bank size increased with surfactant concentration, but the dispersed oil regime was less sensitive to the surfactant concentration.
Further Evidence for Coastal Trapped Waves along the Peru Coast

Abstract Time series of coastal sea level during 1976–77, from 2°12′S to 17°S along the west coast of South America, show that low-frequency, ω < 0.25 cycles per day (cpd), fluctuations propagate poleward with the phase speed of baroclinic Kelvin waves (2–3 m s−1). The alongshore coherence is highest in the frequency band 0.1–0.2 cpd. Computing the frequency-domain empirical orthogonal functions (EOF) for alongshore current, from an army of current meters extending from 5°S to 15°S during March-May 1977, gives 70% of the variance in the 0.1–0.2 cpd frequency band to an EOF mode with poleward phase propagation at 2.75 m s−1. The vertical structure of the alongshore current fluctuations (0.1–0.2 cpd) over the continental slope at 5°S and 15°S is consistent with a first-mode baroclinic Kelvin wave. The current and sea-level fluctuations are coherent and propagate poleward through latitudes where their frequency equals the local inertial frequency. The fluctuations are not significantly coherent with coastal .
Aeolian creeping mass of different grain sizes over sand beds of varying length

Creep is an important mode of aeolian sand transport, but it has received little attention in previous studies due to experimental difficulties and insufficient theory. In this study, we conducted 116 groups of experiments with three repeats for each group in a wind tunnel to measure the creeping mass of four different mean grain sizes (152, 257, 321, and 382 µm) over six bed lengths (2.0, 3.5, 5.0, 6.5, 8.0, and 10.0 m) at six different friction velocities (0.23, 0.35, 0.41, 0.47, 0.55, and 0.61 m/s). We attempted to develop a comprehensive model of the aeolian creeping mass by analyzing the effect of wind velocity, the particle size, and the sand bed length based on the experimental data. The primary conclusions are as follows: (1) the complex relationship among the wind velocity, the grain size, the length of the bed, and the surface shape determines sand creep. There was no unified formula to express the effect of particle sizes and the sand bed length on aeolian creeping masses, and their effects appeared to depend on each other and wind velocity, whereas the creeping mass increases with increasing wind velocity for any particle size with any length of sand bed. (2) This paper presented a predicting model to determine the aeolian creeping mass, whose calculating results can match to experimental data with correlation coefficients (R2) of 0.94 or higher. (3) The effect of grain size on creeping mass can be classified into three categories: the creeping mass increases with increasing grain size, the creeping mass initially decreases and subsequently increases with increasing grain size, and the creeping mass fluctuates with the grain size. (4) The effect of increasing bed length appears to depend on the grain size. For mean grain sizes of 152, 257, and 321 µm, creep initially increases with increasing bed length before decreasing above a certain value, while for a mean grain size of 382 µm, the creeping mass gradually increased with increasing bed length. The results help to elucidate aeolian creep and provide an intense foundation for advanced study.
The evolution of the equatorial thermocline and the early Pliocene El Padre mean state

The tropical Pacific thermocline strength, depth, and tilt are critical to tropical mean state and variability. During the early Pliocene (~3.5 to 4.5 Ma), the Eastern Equatorial Pacific (EEP) thermocline was deeper and the cold tongue was warmer than today, which resulted in a mean state with a reduced zonal sea surface temperature gradient or El Padre. However, it is unclear whether the deep thermocline was a local feature of the EEP or a basin‐wide condition with global implications. Our measurements of Mg/Ca of Globorotalia tumida in a western equatorial Pacific site indicate Pliocene subsurface temperatures warmer than today; thus, El Padre included a basin‐wide thermocline that was relatively warm, deep, and weakly tilted. At ~4 Ma, thermocline steepening was coupled to cooling of the cold tongue. Since ~4 Ma, the basin‐wide thermocline cooled/shoaled gradually, with implications for thermocline feedbacks in tropical dynamics and the interpretation of TEX86‐derived temperatures.