Miracle-dz/UniFAR-FTUs huggingface dataset:
Assessment of tillage effects on soil quality of pastures in South Africa with indexing methods

Soil quality of pastures changes through time because of management practices. Excessive soil disturbance usually leads to the decline in soil quality, and this has resulted in concerns about kikuyu (Pennisetum clandestinum)–ryegrass (Lolium spp.) pasture systems in the southern Cape region of South Africa. This study aimed to understand the effects of tillage on soil quality. The soil management assessment framework (SMAF) and the locally developed soil quality index for pastures (SQIP) were used to assess five tillage systems and were evaluated at a scale inclusive of variation in topography, pedogenic characteristics and local anthropogenic influences. Along with assessment of overall soil quality, the quality of the physical, chemical and biological components of soil were considered individually. Soil physical quality was largely a function of inherent pedogenic characteristics but tillage affected physical quality adversely. Elevated levels of certain nutrients may be warning signs to soil chemical degradation; however, tillage practice did not affect soil chemical quality. Soil disturbance and the use of herbicides to establish annual pastures has lowered soil biological quality. The SQIP was a more suitable tool than SMAF for assessing soil quality of high-input, dairy-pasture systems. SQIP could facilitate adaptive management by land managers, environmentalists, extension officers and policy makers to assess soil quality and enhance understanding of processes affecting soil quality.
Effects of tectonism and magmatism on crack structure in oceanic crust: A seismic anisotropy study

We analyzed 25,675 traveltime residuals from a three-dimensional seismic tomographic inversion to investigate crack-induced seismic anisotropy in the upper oceanic crust. The study covered two regions with contrasting levels of magmatic activity on the western limb of the 9°N overlapping spreading center on the East Pacific Rise. The level of anisotropy gradually decreases with depth in the magmatically and hydrothermally active ridge region. In contrast, we observed a highly variable anisotropic structure in the magmatically and hydrothermally less active tip region at the end of the dying ridge segment: a weakly anisotropic layer beneath strongly anisotropic extrusive volcanic rocks is likely to be the result of relatively shallow cracks closed by hydrothermal precipitation. Strongly anisotropic dikes with inferred narrow and water-saturated cracks provide important along-axis pathways for the circulation of hydrothermal fluids beneath the shallow cracks in the less magmatically active regions. Furthermore, a significant clockwise rotation (20°–30°) of fast directions occurs in both regions with increasing depth. Such a rotation provides evidence that the geometry of the underlying crack structure of the western limb is significantly different from that defined by the bathymetric ridge crest.
The influence of discharge and temperature on the ability of upstream migrant adult river lamprey (Lampetra fluviatilis) to pass experimental overshot and undershot weirs

The efficiencies of fish passes specifically designed and constructed to facilitate the movement of a limited number of species and life‐stages past structural barriers are likely to decline as site‐specific conditions shift with a changing climate. There is a need to develop realistic fish passage criteria based on understanding swimming capability and behaviour of multiple species in relation to temperature and flow. The influence of temperature and discharge on behaviour and ability of groups of migrating adult river lamprey (Lampetra fluviatilis), a threatened species, to pass a small overshot or undershot weir at night was investigated using a large experimental flume. Lamprey approached the weirs less, and more often maintained station by using the oral disk to attach to structure, under high flows. Oral disk attachment was more commonly observed during tests employing the undershot weir. Upstream movement tended to be in close proximity to the channel walls and floor where, compared to the mid‐channel, velocities were generally lower and velocity vectors more likely to be in a direction other than the bulk flow. Upstream movement was positively related to temperature, and was higher for the overshot weir. Weir passage rate was higher for undershot than overshot weirs, and negatively related to the maximum velocity at the weir. Passage rate was low when maximum velocities at the weir exceeded 1.5 m s−1, although some fish passed at c. 1.7 m s−1. Passage efficiency, the number of weir passes as a percentage of the number of approaches, was also higher for the undershot weir, but was not affected by discharge because lamprey approached less frequently at high flows. This study provides fish passage criteria under realistic conditions for an infrequently studied anguilliform species of conservation concern and provides a methodological perspective by which to improve fishway suitability for a wider range of species subject to changing climate. Copyright © 2010 John Wiley & Sons, Ltd.
Report on the SEG/KOC joint workshop in Kuwait: Seismic multiples — Are they signal or noise?

In December 2014, SEG and Kuwait Oil Company (KOC) held a joint workshop in Kuwait City to advance the understanding of seismic multiples and to provide answers to the question posed in the title of the workshop, “Seismic multiples — Are they signal or noise? ” Indeed, despite recent advances in the prediction of multiples as noise and in their imaging as signal, the processing of multiples in seismic data remains a major challenge for the industry.
Evolution of sulfide mineralization on Mars

The presence of komatiitic igneous rocks on Marks, based on geochemical evidence from SNC meteorites and Viking X ray fluorescence analyses of the regolith, suggests that massive and disseminated iron sulfide mineralization occurs near the Martian surface. Analogies are drawn between possible ultramafic Fe-Ni sulfides on Mars and terrestrial pyrrhotite-pentlandite ore deposits associated with Archean komatiites formed during early crustal development on Earth. Partial melting of the mantle as a result of high radiogenic heat production then, extrusion of turbulent high-temperature ultramafic lavas, segregation of immiscible FeS melts during cooling, gravitational settling and fractional crystallization of sulfide minerals in magma chambers or lava flows produced massive and disseminated sulfide mineralization associated with terrestrial komatiites. Comparable processes probably occurred on Mars where, on account of the inferred higher Fe/(Fe + Mg) ratio of the X ray mantle (estimated to contain {approximately}4.5 wt % S), iron-rich basaltic magmas were produced by partial melting at depths and temperatures exceeding 165 km and 1,400{degree}C, respectively. Adiabatic diapiric emplacement of these iron-rich, very low viscosity basaltic melts transported significant concentrations of dissolved sulfur as S{sup 2{minus}} and HS{sup {minus}} from the mantle. Ensuing sulfide mineralization may have been either thinly disseminated within ultramafic lavas eruptingmore » over large areas of Mars or concentrated locally at the base of structural depressions. Cumulate ore deposits several meters thick may occur at the base of intrusions or in near-surface magma chambers. The evidence for insignificant plate tectonic activity on Mars and minimal interactions of Martian mantle with crust, hydrosphere and atmosphere has restricted the evolution of sulfide ore deposits there. « less
The Magnitude of Decadal and Multidecadal Variability in North American Precipitation* , 1

The authors use singular spectrum analysis to investigate the relative magnitude of decadal to multidecadal (D2M) variability in annual and seasonal precipitation anomalies across North America. In most places, decadal (10–20 yr) or multidecadal (20–50 yr) variability makes up less than 10% of the total variance in either annual or seasonal precipitation, with interannual variability or secular trends having much greater importance. Decadal variability is most prominent (contributing 25%–30% of the total variance) in Min- nesotaand northernCaliforniaduringwinter,andthecentralRockyMountainsinautumn.EasternQue´becis theonly majorregion where precipitation exhibitssigniﬁcant variancein the multidecadal band. Precipitation across much of Canada exhibits signiﬁcant variance at extremely low frequencies (greater than 50 yr), but variability at these time scales cannot be separated from secular trends because of the limited length of instrumentalclimaterecords.DecadalsignalsinthedischargeoftheSacramentoRiverand,toalesserdegree, the Colorado River are coherent and in phase with similar signals in regional precipitation. Prominent D2M signals do not resemble the low-frequency components of major climate modes such as ENSO or the PDO, which suggests that this behavior is not a product of a simple linear translation of a single climate forcing.
Rise and decline of active chlorine in the stratosphere

Our ground‐based millimeter‐wave measurements of chlorine monoxide (ClO) in the ozone layer above Hawaii since 1992, together with a few measurements from the same site using an earlier version of the same instrument during the 1980's, provide a unique data set for the determination of the long‐term trend of active chlorine in the middle stratosphere. The trend shows a rapid rise of 58% from 1982 to a broad maximum in 1994–1997 and a substantial decline of 1.5%/year from the maximum through late 2004. About 1/3 of the decline may be due to changes in methane. Both the rise and the decline are consistent with that expected from the rise and decline of total chlorine in the troposphere, which reached a maximum in 1992–1993, then declined sharply after implementation of international agreements to phase out chlorofluorocarbon (CFC) production starting with the Montreal Protocol.
Pesticides in Stream Sediment and Aquatic Biota: Distribution, Trends, and Governing Factors

Introduction Purpose Previous Reviews Approach Characteristics of Studies Reviewed General Design Features Geographic Distribution Temporal Distribution Sampling Matrices Target Analytes Analytical Detection Limits National Distribution and Trends Pesticide Occurrence National Pesticide Use Geographic Distribution in Relation to Use Long-Term Trends Governing Processes Pesticide Sources Behavior and Fate of Pesticides in Bed Sediment Behavior and Fate of Pesticides in Aquatic Biota Analysis of Key Topics - Sources, Behavior, and Transport Effect of Land Use on Pesticide Contamination Pesticide Uptake and Accumulation by Aquatic Biota Seasonal Changes in Pesticide Residues Physical and Chemical Properties of Pesticides in Sediment and Aquatic Biota Composition of Total DDT as an Indicator of DDT Sources and Period of Use Analysis of Key Topics - Environmental Significance Effects of Pesticide Contaminants on Aquatic Organisms and Fish-Eating Wildlife Effects of Pesticide Contaminants in Aquatic Biota on Human Health Summary and Conclusion Appendix A: Table 2.1 Pesticides in bed sediment and aquatic biota from rivers and estuaries in the United States: National and multistate monitoring studies Appendix B: Table 2.2 Pesticides in bed sediment and aquatic biota from rivers in the United States: State and local monitoring studies Appendix C: Table 2.3 Pesticides in bed sediment and aquatic biota from rivers in the United States: Process and matrix distribution studies Appendix D: Common Names and Taxonomic Classifications of Aquatic Organisms Sampled in the Studies Reviewed Appendix E: Glossary of Common and Chemical Names of Pesticides References Index
Geological manifestations of ridge collision: Evidence from the Golfo de Penas-Taitao Basin, southern Chile

Recent geological and geophysical studies in the southern Andes adjacent to the intersection of the Chile Rise with the Peru-Chile Trench (ANT-NAZ-SAM triple junction) have revealed a number of features and a Neogene geologic history that are unique along the Pacific margin of South America. This history includes (1) development of a Tertiary-Quaternary marine basin with up to 3 km of sediment infill (Golfo de Penas-Taitao basin, GTB), (2) disruption of the region by a series of faults with both normal and strike slip movements, and (3) localization of silicic, near-trench volcanism and epizonal plutonism and related hydrothermal activity. The northern portion of the GTB began to subside in the Late Miocene (possibly earlier), and has subsequently been deformed, uplifted, and exposed. Gravity and seismic reflection data suggest that the basin continues offshore where it is still actively subsiding today (Golfo de Penas). Subsidence and uplift have thus occurred diachronously in the region, although it is unclear when subsidence began in the Golfo de Penas. Tectonic disruption of the region is likely related to the Liquine-Ofqui fault (LOF), a major, NS-trending, crustal shear zone that curves westward and terminates in the Golfo de Penas. The LOF has both down-to-the-west and right lateral offset and separates the main Andean Cordillera on the east from a large crustal block (the Chiloe block) on the west. We hypothesize that the GTB has developed as a pull-apart basin in response to northward movement of the Chiloe block along the LOF. We propose a dynamic model whereby a stress gradient that decreases longitudinally away from the Chile Rise/Peru-Chile Trench intersection is set up because the youngest, most buoyant, oceanic lithosphere is being subducted at the triple junction. The Chile Rise is viewed as a type of indenter which is acting to drive the Chiloe block northward in front of the northward-migrating triple junction. This model explains the unique set of geologic features found in the region, and suggests that ridge-trench interactions may be an important factor in orogenesis at active continental margins.
Genesis of Archean komatiites from Munro Township, Ontario: Trace-element evidence

Trace elements, particularly rare earths, determined in Archean komatiitic and tholeiitic rocks of Munro Township, Ontario, appear mainly to reflect the processes that produced the lavas, rather than the metamorphic processes. Pyroxenitic to basaltic komatiites may have originated by fractional crystallization of peridotitic komatiite liquid or by partial melting of plagioclase peridotite in the mantle. Peridotitic komatiite magmas may be partial melts of a residual mantle assemblage that was depleted in largeion lithophile (LIL) elements, possibly through earlier extraction of liquids. Picritic tholeiites may have originated from melting of garnet peridotite. A multistage melting model may relate both tholeiites and komatiites to a common source, perhaps in a rising mantle diapir. In this model tholeiites would be the first-formed liquids extracted whereas residual mantle might be further melted to produce komatiitic liquids.
Correlated Millennial-Scale Changes in Surface Hydrography and Terrigenous Sediment Yield Inferred from Last-Glacial Marine Deposits off Northeastern Brazil

The stable isotope composition of planktonic foraminifera correlates with evidence for pulses of terrigenous sediment in a sediment core from the upper continental slope off northeastern Brazil. Stable oxygen isotope records of the planktonic foraminiferal species Globigerinoides sacculiferand Globigerinoides ruber(pink) reveal sub-Milankovitch changes in sea-surface hydrography during the last 85,000 yr. Warming of the surface water coincided with terrigenous sedimentation pulses that are inferred from high XRF intensities of Ti and Fe, and which suggest humid conditions in northeast Brazil. These tropical signals correlate with climatic oscillations recorded in Greenland ice cores (Dansgaard-Oeschger cycles) and in sediment cores from the North Atlantic (Heinrich events). Trade winds may have caused changes in the North Brazil Current that altered heat and salt flux into the North Atlantic, thus affecting the growth and decay of the large glacial ice sheets.
The stabilization role of groundwater when surface water supplies are uncertain: The implications for groundwater development

When used in conjunction with surface water for irrigation, groundwater serves two roles: to increase water supply; and to mitigate fluctuations in the supply of water. The later is the buffer role. This paper identifies and evaluates the economic benefit associated with the buffer role of ground water. Implications for the development of groundwater resources are investigated. An estimate is given of the buffer benefit to wheat growers of the fossil water aquifer underlying the Israeli Negev. It is found that, under the prevailing variability in the supply of surface water, this benefit may well exceed the groundwater benefit associated with the increase in water supply.
Influence of water flux and redox conditions on chlorobenzene concentrations in a contaminated streambed

Significant natural attenuation may occur on the passage of groundwater plumes through streambed sediments because of the transition from anaerobic to aerobic conditions and an increased microbial activity. Varying directions and magnitudes of water flow in the streambed may enhance or inhibit the supply of oxygen to the streambed and thus influence the redox zoning. In a field study at a small stream in the industrial area of Bitterfeld‐Wolfen, we observed the variability of hydraulic gradients, streambed temperatures, redox conditions and monochlorobenzene (MCB) concentrations in the streambed over the course of 5 months. During the observation period, the hydrologic conditions changed from losing to gaining. Accordingly, the temperature‐derived water fluxes changed from recharge to discharge. Redox conditions were highly variable between − 170 and 368 mV in the shallow streambed at a depth of 0·1 m below the streambed surface. Deeper in the streambed, at depths of 0·3 m and 0·5 m, the redox conditions were more stable between − 198 and − 81 mV and comparable to those typically found in the aquifer. MCB concentrations in the streambed at 0·3 and 0·5 m depth increased with increasing upward water flux. The MCB concentrations in the shallow streambed at 0·1 m depth appeared to be independent of the hydrologic conditions suggesting that degradation of MCB may have occured. Copyright © 2010 John Wiley & Sons, Ltd.
Magma chamber dynamics recorded by oscillatory zoning in pyroxene and olivine phenocrysts in basaltic lunar meteorite Northwest Africa 032

Abstract Oscillatory zoning in silicate minerals, especially plagioclase, is a common feature found in volcanic rocks from various terrestrial tectonic settings, but is nearly absent in the lunar environment. Here we report backscattered electron images, quantitative wavelength-dispersive spectrometry (WDS) analyses, and qualitative WDS elemental X‑ray maps that reveal oscillatory zoning of Mg, Ca, Fe, Ti, Al, Cr, and Mn in euhedral pyroxene phenocrysts, and faint oscillatory zoning of P in olivine phenocrysts in basaltic lunar meteorite Northwest Africa (NWA) 032. This is only the third known occurrence of oscillatory zoning in lunar silicate minerals. Zoning bands in pyroxene range from ~3-5 μm up to ~60 μm in width, but are typically ~10-20 μm in width. Oscillatory bands are variable in width over short distances, often within a single grain. Most oscillatory bands preserve a euhedral form and have sharp edges; however some bands have jagged or uneven edges indicative of resorption surfaces. The short-scale oscillatory nature of the zoning in pyroxene is overprinted on longer-scale core to rim normal magmatic zoning from pigeonite to augite compositions. Oscillatory zoning of P in olivine is faint and only resolvable with high beam current (400 nA) mapping. Bands of higher P are typically only a few micrometers in width, and although they preserve a euhedral form, they are not traceable around the full circumference of a grain and have variable spacing. Resorption surfaces, longer-scale normal magmatic zoning, and relatively thick oscillatory bands are indicative of the formation of these chemical oscillations as a result of variable magma composition. Pyroxenes likely experienced variable liquid compositions as a result of convection in a differentially cooling, chemically stratified magma chamber. Periodic replenishments of progressively decreasing volumes of primitive parental magma are also permissible and may have enabled convection. In a convection model, Mg-rich bands reflect growth in the lower, warmer, more crystal-poor regions of the chamber, whereas Ca-Al-Ti-Cr-rich bands reflect growth in the upper, cooler, more crystal-rich regions of the chamber. The limited duration of crystallization in the magma chamber and the slow diffusion rates of multiple elements among multiple crystallographic sites in clinopyroxene, combined with fast cooling upon eruption, act to preserve the oscillatory zoning. Oscillatory zoning of P in olivine is a product of solute trapping resulting from the slow diffusion of P in silicate melts and minerals, and relatively fast magma cooling rates that may be related to magma chamber convection. Differential cooling of the chamber and the fast cooling rates within the chamber are likely a product of the thermal state of the lunar crust at 2.93 Ga when NWA 032, which is currently the youngest dated lunar igneous rock, erupted onto the surface of the Moon.