Miracle-dz/UniFAR-FTUs huggingface dataset:
Lithium in carbonatites - consequence of an enriched mantle source?

Abstract The rare Li-mica taeniolite is described from the Dicker Willem carbonatite complex, Namibia, and from the Alpine carbonatitic lamprophyre dyke swarm at Haast River, New Zealand. At Haast River, taeniolite occurs in sodic and ultrasodic fenites derived from quartzo-feldspathic schists and rarely in metabasites, adjacent to dykes of tinguaite, trachyte and a spectrum of carbonatites ranging from Ca- to Fe- rich types. In Namibia, taeniolite is present in potassic fenites derived from quartz-feldspathic gneisses and granitoids at the margin of an early sövite phase of the complex and in a radial sövite dyke emanating from this centre. The occurrence of taeniolite in these totally disparate carbonatite complexes, together with examples of lithian mica from other carbonatite complexes worldwide, raises the question of the status of Li as a 'carbonatitic element'. We argue that lithium is not a consequence of crustal assimilation or interaction, but reflects the geochemical character of the magmatic source. Li, an overlooked and little-analysed element, may be an integral part of metasomatic enrichment in the mantle, and of magmas derived by partial melting of such a source.
Mars atmospheric dynamics as simulated by the NASA Ames General Circulation Model: 1. The zonal‐mean circulation

This is the first in a series of papers that will discuss Mars atmospheric dynamics as simulated by the NASA Ames General Circulation Model (GCM). This paper describes the GCM's zonal-mean circulation and how it responds to seasonal variations and dust loading. The results are compared to Mariner 9 and Viking observations, and the processes responsible for maintaining the simulated circulation are discussed. At the solstices the zonal-mean circulation consists of a single cross-equatorial Hadley circulation between 30°S and 30°N. For relatively modest dust loadings (τ=0.3), the associated peak mass flux is 100 × 108 kg s−1 at northern winter solstice and 55 × 108 kg s−1 at southern winter solstice. At both seasons, westerlies dominate the winter hemisphere, and easterlies dominate the summer hemisphere. Maximum zonal winds occur near the model top (∼47 km) and are about the same at both seasons: 120 m s−1 in the winter hemisphere and 60 m s−1 in the summer hemisphere. Mean surface westerlies of 10–20 m s−1 are predicted at the middle and high latitudes of the winter hemisphere, as well as in the summer hemisphere near the rising branch of the Hadley circulation. The latter has the structure of a “jet” and is particularly strong (>20 m s−1) at northern winter solstice. With increasing amounts of dust (up to τ=5), the zonal mean circulation at northern winter solstice intensifies and gives no indication of a negative feedback. Dust can easily double the mass flux of the Hadley circulation. In the solstice simulations, the mean meridional circulation is the main dynamical contributor to the heat and momentum balance; the eddies play a relatively minor role. There is no evidence in these simulations for a polar warming. At the equinoxes the zonal mean circulation is more Earth-like and consists of two roughly symmetric Hadley cells with westerly winds in the mid-latitudes of each hemisphere and easterlies in the tropics. The simulated zonal winds are about half as strong as they are at solstice. However, the strength of the mean meridional circulation is much less than at solstice and averages between 5 and 10 × 108 kg s−1. At these seasons, the eddies and mean circulation make comparable, but opposing, contributions to the heat and momentum balances.
Seismic Behavior of Cantilever Retaining Walls with Liquefiable Backfills

A series of centrifuge tests were conducted to investigate the seismic behavior of fixed-base, cantilever, retaining walls supporting saturated, liquefiable, cohesionless backfills. Accelerations, bending strains, deflections, and lateral earth pressures were measured on the walls. Accelerations, pore pressures, and surface settlements were measured in the soil. Parametric studies investigating effects of wall stiffness and magnitude of shaking on the wall-soil behavior were conducted. The magnitude and distribution of lateral earth pressures were determined. Experimental results demonstrated that excess pore pressures in liquefiable backfills contribute significantly to seismic, lateral, earth pressures. It was shown that the average rise in the dynamic thrust is well correlated to the excess pore pressures in the backfill but is insensitive to the range of wall stiffness. It was found that simple calculations, based on Coulomb's active earth pressure theory, can be used to estimate the dynamic thrust at.
Source parameters of the swarm earthquakes in West Bohemia/Vogtland

The self-similarity of earthquake rupture scaling is a subject of ongoing debates. The output of multiple recent studies agrees on the fact that stress drops of earthquakes varies from 0.1 to 100 MPa over a broad range of seismic moments. We investigated the source parameters of 56 earthquakes in the magnitude range M L from 0.8 to 3.3 occurred during the 2000 and 2008 swarm in West Bohemia/Vogtland in order to learn if the source scaling of these, most-likely ﬂuid triggered events, differ from the observations in other seismogenic regions around the world. We used two approaches to calculate the corner frequency in the frequency domain: inverting for the corner frequency f c of the displacement spectra and integrating of spectra by the method of Snoke. A single f c for all stations was determined with attenuation correction deﬁned by inverting for an event-dependent Q -factor. Similar dependence of the corner frequency on seismic moment was observed in the form f c ∝ M 0 − 0.2 , which is a much weaker scaling than expected for a constant stress drop model. Accordingly, the stress drops vary from 1 to 130 MPa and appears to grow with seismic moment as (cid:2)σ ∝ M 00.43 . The non-self similarity of the swarm earthquakes is supported by rather wide span of apparent stress ranging between 0.3 kPa and 1.2 MPa.
Microbial production of CO2 in unsaturated geologic media in a mesoscale model

The production of microbially derived CO2 was investigated in the 3.6 m thick unsaturated geologic media of a mesoscale model system. The mesoscale model, which was 2.4 m diameter × 4.6 m high, was filled with a medium grained lacustrine sand, capped with an Ap (0.11 m) and B (0.20 m) soil profile, and maintained under steady state moisture conditions for 343 days. A near steady state soil gas CO2 concentration profile (>100 times greater than atmospheric) developed after 130 days implying that geochemical stability was rapidly attained. The presence of metabolically active microorganisms, consumption of O2 and dissolved organic carbon, and carbon 13 data indicated that the CO2 was microbially produced. At steady state, the calculated and modeled CO2 flux to the atmosphere (about 0.9 mol m−2 day−1) were greater than the measured CO2 flux (0.1 mol m−2 day−1) and greater than the calculated CO2 flux to the water table (0.02 mol m−2 day−1). The difference between the calculated and measured fluxes of CO2 to the atmosphere was attributed to spatial variability in the gas diffusion coefficient and reflected the difficulty in estimating CO2 production, even under steady state conditions. Laboratory estimates of microbial CO2 fluxes (1.8 and 2.9×103 mol m−2 day−1 ) were much greater than those determined from measured and calculated fluxes. Measured microbial respiration rates suggested that between 50 and 70% of the respired CO2 was produced in the unsaturated geologic medium beneath the Ap and B, and that there was sufficient CO2 production potential by bacteria to account for the respired CO2 determined from the flux calculations. These observations indicated that long-term experimentation in mesoscale models can overcome some of the difficulties encountered in field studies and provide insight into biogeochemical processes in natural systems.
Correlations between the classic Paraná and Cape–Karoo sequences of South America and southern Africa and their basin infills flanking the Gondwanides: du Toit revisited

Abstract Early during the twentieth Century, pioneering correlations between the Palaeozoic–Mesozoic basins of South America and southern Africa were used by Alexander du Toit to support the initial concepts of continental drift and the proposal of a united Gondwana continent. New stratigraphic tools and data can now be used to further tease out similarities and differences to reconstruct the detailed histories of these, the Paraná and Cape–Karoo basins. In turn this knowledge can be used also to increase our understanding of the origin and evolution of Gondwana. Recent advances in tectonics and stratigraphy showed that both basins evolved together along a common early Palaeozoic Gondwana margin facing the Panthalassa. Thereafter, this margin was transformed into a series of linked foreland basins coupled to the evolution of the Gondwanides. In detail, the foreland successions differ considerably due to spatial and temporal differences in tectonic histories along the Gondwanides. Only towards the end of the Palaeozoic did both basins evolve and merge into a single continental-scale, and truly intracratonic, terrestrial Gondwana basin that persisted until the early Cretaceous. This shared history was once again disrupted in the Early Cretaceous during the opening of the South Atlantic Ocean.
Improved Thermal Computations for Artificially Frozen Shaft Excavations

Artificial ground freezing (AGF) techniques are widely used by civil and mining engineers to assist in the construction of shafts, tunnels, and other structures. The ground is frozen by a coolant circulated through pipes inserted in the ground in order to create a cofferdam that will exclude ground water and provide structural support. Formulas by Sanger and Sayles are often used to estimate the growth of the freeze. The theoretical basis of these formulas are critically examined and an alternative method of computing the extent of the frozen ground is given. The alternative method is based on some of the ideas of Sanger and Sayles and requires the numerical solution of one diffusion equation over a finite interval. Numerical results are presented using typical data for granular soils with several different dry densities and water contents.
Elemental and Sr-Nd-Pb isotopic compositions of late Cenozoic Abaga basalts, Inner Mongolia: Implications for petrogenesis and mantle process

The Abaga volcanic field is one of the largest and least known areas of late Cenozoic intraplate igneous activities in eastern China. Twenty-seven Abaga basaltic rocks were analyzed for major and trace element contents, Sr‐Nd‐Pb isotopic compositions, and K‐Ar dating. These basalts predominantly consist of alkali basalt with subordinate transitional olivine tholeiite and rare quartz tholeiite. Combining our data of ten K‐Ar dates with previously published data showed that the time of the principal volcanic eruption was from the Miocene to the Quaternary (14.57~0.19 Ma). A large amount of volcanic activity is believed to have begun in the northwestern portion of the AVF and gradually migrated southeastwards with geological time. The Abaga basalts exhibit chondrite-normalized REE patterns, incompatible elements and isotopic ratios ( 87 Sr/ 86 Sr of 0.703654~0.704286 and 143 Nd/ 144 Nd of 0.512845~0.512891) affiliated with oceanic island basalts (OIBs). In general, they have relatively homogenous Pb isotopic compositions ( 206 Pb/ 204 Pb of 18.409~18.521, 207 Pb/ 204 Pb of 15.514~15.546, and 208 Pb/ 204 Pb of 38.259~38.447), indicating that these lava suites have a similar source. But the alkali basalts are relatively enriched in incompatible elements when compared to the tholeiites. This compositional difference may be attributable to the different degrees of partial melting in the mantle source. The Sr‐Nd‐Pb isotopic data indicated that the mantle sources of the late Cenozoic Abaga basalts display a DMM-EM2 array similar to those of Southeast Asia. The 208 Pb/ 204 Pb vs. 206 Pb/ 204 Pb plot was also significantly displaced above the Northern Hemisphere reference line in a pattern clustering near the less-depleted end of the field for the Indian Ocean mid-oceanic ridge basalt (MORB) that shows Dupal signatures. Therefore, we suggest that the Abaga basaltic magmas were dominantly derived from an Indian Ocean MORB-like depleted asthenospheric source with fewer contributions of an enriched mantle component (EM2) from the subcontinental lithospheric mantle.
CO2 evolution and short‐term carbon turnover in stable soil organic carbon from soils applied with fresh organic matter

The organic carbon of particle size <53 μm is mineral‐associated organic carbon (MAOC), the measurable fraction of passive soil organic matter pool described in CENTURY model. We studied the effect of fresh organic matters (FOMs): no OM (control); chicken manure (CM): 2.12 g CM carbon kg−1; and leaf litter (LL): 1.81 g LL carbon kg−1 on short‐term dynamics of MAOC and CO2 evolution of two soils: Bagabag, Philippines (121°15′E, 16°35′N) and Tsumagoi, Japan (138°30′E, 36°30′N). Cumulative CO2 evolution was significantly higher in CM‐applied soils. Significant MAOC decrease in 5–20‐cm depth of Tsumagoi soil suggest short‐term stable C turnover even with FOM application. Greater MAOC decline in CM‐applied Bagabag soil suggest that manure application may result to bigger stable C turnover in this soil. Our results provide evidence of significant short‐term stable SOC turnover, and challenge the convention that only labile SOC is involved in short‐term CO2 evolution from soils.
Cranial anatomy of a new plesiosaur genus from the lowermost Lias (Rhaetian/Hettangian) of Street, Somerset, England

ABSTRACT A newly prepared plesiosaur skull collected by Thomas Hawkins (1810–1889) from the Lias quarries of Street, Somerset, England, provides important indications of character polarity within the Plesiosauria. Many features of the 3-dimensional, matrix-free skull are seemingly plesiomorphic in accord with the early, probably latest Rhaetian, stratigraphic position of the specimen. The small supratemporal fenestrae, elongate jugals, deeply excavated cheek, spatulate mandibular symphysis, and other characters thus have important implications for phylogenetic studies of the Plesiosauria. A new genus is erected to include the skull and several other specimens of historical importance that comprise part of the oldest known fauna of fully articulated plesiosaurs.
THE IMPACT OF GOVERNMENT EXPENDITURE ON ECONOMIC GROWTH IN KENYA: 1963-2008

The rapid growth in government expenditure in Kenya has caused concern among policy makers on the implication of such growth. Over the three decades, government expenditure in the country grew at a faster rate than the growth rate of GDP. Given this fiscal scenario, an explanation of this requires studying the impact of government expenditure on economic growth. The specific objectives of the study were to: investigate the relationship between the components of government expenditure and economic growth; examine the effects of components of government expenditure on GDP growth rate; analyze the effects of government expenditure reforms on economic growth; and to draw policy implications from the findings. The data used were government expenditure components that included expenditure on government investment, physical infrastructure, education, health care, public debt servicing, economic affairs, general administration and services, defense, public order and national security, and government consumption. Sources of data were Kenya government documents and international financial statistics publications. The study applied Vector Auto Regression estimation technique using the annual time series data for the period 1963 to 2008 to evaluate the impact of government expenditure on economic growth. The Johansen cointegration tests revealed a long-run relationship between GDP growth rate and the selected components of government expenditure. Further, the Granger- Causality test indicated bi-directional causality between GDP growth rate and components of government expenditure. The results of impulse response functions and variance decomposition revealed that government expenditure on investment, physical infrastructure, education, health care, public debt servicing, economic affairs, general administration and services, defense, public order and national security and government consumption have effect on economic growth. Furthermore, the study established that expenditure reforms of budget rationalization, expenditure downsizing, privatization and governance affect economic growth. The study concludes that the composition of government expenditure and public expenditure reforms matter for economic growth.
Ice wastage and landscape evolution along the southern margin of the Laurentide Ice Sheet, north‐central Wisconsin

The Chippewa and Wisconsin Valley Lobes of the Laurentide Ice Sheet reached their maximum extent in north-central Wisconsin about 20 000 years ago. Their terminal positions are marked by a broad area of hummocky topography, containing many ice-walled-lake plains, which is bounded on the up-ice and down-ice sides by ice-contact ridges and outwash fans. The distribution of these ice-disintegration landforms shows that a wide zone of stagnant, debris-covered, debris-rich ice separated from the active margins of both lobes as they wasted northward during deglaciation. Accumulation of thick, uncollapsed sediment in ice-walled lakes high in the ice-cored landscape indicates a period of stability. In contrast, hummocky disintegration topography indicates unstable conditions. Thus, we interpret two phases of late-glacial landscape evolution. During the first phase, ice buried beneath thick supraglacial sediment was stable. Supraglacial lakes formed on the ice surface and some melted their way to solid ground and formed ice-walled lakes. During the second phase, buried ice began to melt rapidly, hummocky topography formed by topographic inversion, and supraglacial and ice-walled lakes drained. We suggest that ice wastage was controlled primarily by climatic conditions and supraglacial-debris thickness. Late-glacial permafrost in northern Wisconsin likely delayed wastage of buried ice until after about 13 000 years ago, when climate warmed and permafrost thawed.
Estimate of carbonyl sulfide (OCS) volcanic source strength deduced from OCS/CO2 ratios in volcanic gases

Measurements of the concentration ratio of OCS and CO2 were made in fumaroles of several volcanoes in Italy and Nicaragua. The values obtained, together with previous published data, demonstrate that the OCS/CO2 ratio is positively correlated with the emission temperature of the gases. It ranges from 10−7.1 to 10−2.7 at the Vulcano (90°C) and Erta'Ale (1130°C) volcanoes, respectively. The global OCS volcanic source strength, deduced from SO2 emission rates, CO2/SO2 and OCS/CO2 ratios in volcanic gases, is estimated to be in the range 6-90 ×109 gOCS per year.
Model for predicting resilient modulus of unsaturated subgrade soil using soil-water characteristic curve

Soil suction (ψ) is one of the key factors that influence the resilient modulus (MR) of pavement subgrade soils. There are several models available in the literature for predicting the MR–ψ correlations. However, the various model parameters required in the existing models are generally determined by performing regression analysis on extensive experimental data of the MR–ψ relationships, which are cumbersome, expensive, and time-consuming to obtain. In this paper, a model is proposed to predict the variation of the MR with respect to the ψ for compacted fine-grained subgrade soils. The information of (i) the MR values at optimum moisture content condition (MROPT) and saturation condition (MRSAT), which are typically determined for use in pavement design practice; (ii) the ψ values at optimum moisture content condition (ψOPT); and (iii) the soil-water characteristic curve (SWCC) is required for using this model. The proposed model is validated by providing comparisons between the measured and predicted MR–.
Facies and sequence controls on the appearance of the Cambrian biota in southwestern Mongolia: implications for the Precambrian–Cambrian boundary

Abstract Neoproterozoic–Cambrian rocks of the Zavkhan Basin (Govi-Altay, western Mongolia) comprise large-scale alternations of siliciclastic- and carbonate-dominated units (cf. ‘Grand Cycles’). Analysis of such depositional sequences near the base of the Cambrian confirms that the distribution of trace fossils, small shelly fossils and calcimicrobial structures was strongly controlled by ecology and taphonomy, corresponding to specific points in a sea-level cycle. Evolution of the Cambrian biota is thus viewed through aseries of narrow time windows, once only for each depositional cycle. Correlation of the Precambrian–Cambrian boundary level on the basis of the first appearance of the Phycodes pedum assemblage is also fraught with difficulty, since stratigraphic resolution may be limited to a single sea-level cycle(c. 1–5 Ma). It is suggested that, in many cases, basin analysis will need to be undertaken before this boundary can be drawn.
Dynamic recrystallization of olivine single crystals during high‐temperature creep

High-temperature creep experiments were made on olivine single crystals under compressional stress to large strains. At strains larger than about 40 to 60%, dynamic recrystllization occurs and cellular wall dislocation structure is formed. Recrystallized grain size dg(µm) and cell wall spacing ds(µm) are dependent upon applied stress σ(MPa) as: and
A Optimality Conditions

We first consider problems (1) and (2). Theorem 8 (Li et al. (2019); Ha et al. (2020)). The matrix M̃ = Ũ Ũ with Ũ ∈ Rn×r is a first-order critical point of the constrained problem (1) if and only if { ∇fs(M̃)Ũ = 0 if rank(M̃) = r ∇fs(M̃) 0 if rank(M̃) < r. The matrix M̃ = Ũ Ṽ T with Ũ ∈ Rn×r and Ṽ ∈ Rm×r is a first-order critical point of the constrained problem (2) if and only if { [∇fa(M̃)] Ũ = 0, ∇fa(M̃)Ṽ = 0 if rank(M̃) = r ∇fa(M̃) = 0 if rank(M̃) < r.
Estimating the variability of the solar flux between 200 and 300 nm

Observations of the solar ultraviolet irradiance during 1979 (solar maximum) by the Solar Backscatter Ultraviolet Experiment on the Nimbus 7 satellite have established that the irradiance at wavelengths between 200 and 300 nm is modulated by solar rotation. This short-term variability, which is of the order of 3% at 200 nm and 1% at 250 nm, is associated with the evolution and rotation on the solar disc of plage areas which are enhanced in ultraviolet emission. By using ground-based Ca II K observations of the fraction of the disc covered by plage during 1979, the intensity ratios for plage to quiet sun emission at these wavelengths have been derived. During the 11-year solar cycle the number of plage regions on the solar disc increases. There is also an accumulation of active network arising from the remnants of decayed magnetic features. A three-component model of the solar irradiance is used to estimate the temporal behavior of the ultraviolet emission between 200 and 300 nm, resulting from changes throughout the solar cycle in the active features on the disc. These calculations suggest that for solar cycle 21 the flux variability at 200 nm is 25%, decreasing to 10% at wavelengths between 210 and 250 nm, and to 2% at 300 nm. Ultraviolet flux variability of this magnitude corresponds to an average increase in the total solar irradiance from 1976 to 1979 of about 0.05%. For comparison, the average reduction in the total solar irradiance from 1976 to 1979 due to sunspot blocking is 0.07%. Because of the enhanced ultraviolet emission from solar active features, the variability of the total solar irradiance during cycle 21 is predicted to be less than is calculated by models which consider only the effects of sunspot blocking. This result is consistent with the need for an added faculae brightening term in total solar irradiance models.