This study quantifies the effects of weather conditions, irrigation, and plant age on yield and alpha-acids content of Czech hop cultivars Saaz, Sládek, Premiant and Agnus in a 25-year long period, ...i.e., from 1993 to 2018. The yields of Czech hop cultivars were increasing for the first three years of plant age until they stabilized and then started to decline slightly for 15 to 20 years until they reached the optimal time for replanting. The highest alpha-acids content in hop cones was achieved in the first year of cultivation, followed by a logarithmic decline in the upcoming years. Rainfall was the most significant factor that positively influenced the yield of Saaz hops with correlations of r = 0.59 and 0.61 (P < 0.01) for total seasonal rainfall (April–August), 0.65 (P < 0.001) and 0.60 (P < 0.01) for daily rainfall above 3 mm, 0.37 (P < 0.05) and 0.58 (P < 0.01) for rainfall in May and 0.50 (P < 0.01) and 0.32 (P < 0.05) in July in the Saaz region and the Stekník farm, respectively. The yield of cultivars Sládek, Premiant and Agnus was not statistically influenced by the amount of precipitation, but there was a positive effect of irrigation level on yield increase with correlations 0.58 (P < 0.01), 0.55 and 0.49 (P < 0.05), respectively. High air temperatures during summer were the most significant factor that negatively influenced the alpha-acids content with the correlations ranging from –0.56 to –0.83. However, cv. Agnus showed a stable weather-independent alpha-acids content.
Historical Pb–Zn mining and smelting in Kabwe in Zambia have made it one of the most polluted cities in the world. Four soil profiles were collected around the smelter and in remote locations, and ...two pine trees (Pinus montezumae L.) were sampled for tree ring cores. These were analyzed for Pb, Zn and Cu contents and Pb isotopic ratio. Furthermore, the C isotopic composition of tree rings was also assessed. High concentrations of metals are present only in the top layers of soil and are higher in soils closer to the smelter (up to 16000 mg kg−1 Pb; 14000 mg kg−1 Zn; 600 mg kg−1 Cu) compared to remote soils (up to 194 mg kg−1 Pb; 438 mg kg−1 Zn; 46 mg kg−1 Cu). Metals are also present in trees and the one located furthest from the slag dump contains higher metal concentrations (up to 6.48 mg kg−1 Pb; 10.6 mg kg−1 Zn; 10.2 mg kg−1 Cu), possibly due to the deposition of wind-blown particles. Results of a sequential extraction procedure (SEP) showed that metal contaminants are not available for tree root uptake and the above-ground processes must be more important. The Pb isotopic ratios of slags, tree rings, and topsoils average at 206Pb/207Pb = 1.15, corresponding to the signature of local ores and smelting slags, thus confirming that the mine and smelter are the main sources of contamination in the area. The results were compared to the historical records of smelter production. Tree ring Pb and Zn concentrations, δ13C and 206Pb/207Pb reveal linear dependence on production with different statistical significance.
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•High contamination originates from the Pb/Zn historical mining and smelting.•The tree ring record reflects the amounts of historical metal production.•Local Pb ore, topsoils, tree rings and geomaterials exhibit the same Pb signature.•Lead concentration, and Pb isotopes show linear dependence on smelter activity.•Contamination originates from wind-blown particles from the open slag dump.
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•Superposed fabrics in a syntectonic pluton record assembly of the Superior Province.•Early frontal terrane convergence occurred at around 2712 Ma in a ‘hot’ mode.•Subsequent dextral ...shearing was localized to terrane boundaries.•The two-stage evolution resembles modern accretionary orogens.
The Canadian Superior Province has become one of the key test pieces to discuss tectonic processes and mechanisms of crustal growth in the Late Archean. The Province consists of a >2.8 Ga proto-cratonic core intruded by voluminous arc-like plutons and surrounded by a series of narrow, elongate ca. 2.8–2.7 Ga juvenile belts, also referred to as terranes or domains. The terranes seem to wrap around the proto-cratonic core and generally young outward, but the kinematics and geodynamic causes of their assembly remain debated. In this paper, we examine the Radisson pluton in northeastern Québec, which intruded the southern, outer edge of the presumed magmatic arc (Bienville domain) along its ~WNW–ESE-trending tectonic boundary with the proto-cratonic crust (La Grande domain). The pluton, dominated by porphyritic monzogranite to quartz monzonite, was emplaced at around 2712 Ma and exhibits complex internal structure resulting from superposed magmatic to solid-state deformations. An early margin-parallel ~WNW–ESE magmatic foliation containing a steep lineation, recognized by the anisotropy of magnetic susceptibility (AMS), is interpreted as recording vertical stretching and horizontal flattening of highly crystallized magma, either due to emplacement and/or pure shear dominated transpression. More widespread, however, is a horizontal lineation within the same foliation that is interpreted as recording post-emplacement, but still syn-magmatic, tectonic strain (~NNE–SSW shortening and boundary-parallel stretching). Upon cooling, localized dextral S–C mylonite zones accommodated further shortening within the pluton whereas undeformed late-stage felsic dikes cross-cut the solid-state fabric at an angle to the pluton margins. We suggest that this structural succession, also reproduced by numerical fabric modeling, is a local-scale signal of a two-stage assembly of the northeastern Superior Province: the frontal, NNE-directed terrane convergence and attachment to the cratonic nucleus, operating in a ‘hot’ regime with voluminous arc-like plutonism, was followed by more localized dextral shearing parallel to terrane boundaries. The latter phase is recorded at the proto-craton margin but also in the outboard Abitibi greenstone belt virtually at the same time (ca. 2700–2690 Ma). In combination, the two-stage evolution and similar deformation distributed over a broad region resemble modern large hot orogens formed in a plate-tectonic regime.
Single crystals of graphite are diamagnetic with a strong crystalline anisotropy. Their magnetic susceptibility measured in alternating fields exhibits a weak, negative in-phase component and a ...relatively strong out-of-phase component due to electric eddy currents. Consequently, if graphite crystals are oriented preferentially by their crystal lattices (LPO) in graphite ore, one would expect a strong anisotropy of magnetic susceptibility (AMS) of the bulk rock. However, the standard AMS, which is the anisotropy of the in-phase component of susceptibility (ipAMS), reflects not only the LPO of graphite, but also the preferred orientation of the paramagnetic and ferromagnetic admixtures. On the other hand, the anisotropy of out-of-phase susceptibility (opAMS) in rocks such as these should directly indicate the graphite LPO due to its strong electrical conductivity, and can therefore be considered free from the contributions of non-conductive paramagnetic and ferromagnetic minerals. These competing factors were tested on natural metamorphic graphite ores near the South Bohemian town of Český Krumlov in the Moldanubian Zone. The ipMS of the ore is very low, 10−6 to 10−4 SI, being positive in some specimens and negative in others, which indicates mixtures with variable proportions of graphite and paramagnetic-ferromagnetic minerals. On the other hand, opMS is exclusively positive, on the order of 10−5 to 10−4, and is strongly indicative of graphite. The degree of opAMS is distinctly high at 200–300%, and the opAMS lineation is closely perpendicular to the metamorphic foliation in ores and wall rocks. All this indicates a conspicuous LPO of graphite in the ore that was probably created during Variscan regional metamorphism and associated ductile deformation.
•Anisotropy of out-of-phase magnetic susceptibility of graphite-bearing rocks and ores.•Origin of magnetic fabrics.•Preferred orientation of graphite by crystal lattice using magnetic methods.•Good correlation of preferred orientation of graphite determined magnetically and non-magnetically.
We present an approach and software for modelling the Compositional Zoning in Garnet and its Modification by diffusion (CZGM), which combines pseudosection modelling using Perple_X and multicomponent ...diffusion in garnet during metamorphism. CZGM uses the initial compositional profile, obtained by Perple_X with application of garnet fractionation, to generate a population of garnets of prescribed size-distribution and to apply multicomponent diffusion along a selected P-T path during prograde metamorphism and subsequent decompression and/or cooling. As an example, CZGM was applied on average pelitic rocks subjected to metamorphism at different temperatures (600 to 800 °C) and time duration of 1–10 Ma. CZGM provides an easy-to-handle tool for petrologists to examine hypothetical scenarios of garnet development along prograde and retrograde paths and to constrain the P-T path of the whole metamorphic event. By treatment of laboratory measured garnet-bearing metamorphic rocks, it allows to improve the accuracy of pressure and temperature conditions, usually estimated only from compositional isopleths of garnet.
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•A software combining pseudosection modelling and diffusion in garnet is developed.•Predicting compositional zoning in garnets along arbitrary P-T paths.•Time duration of metamorphic process based on diffusion in garnet.
Radioactive (radon) groundwaters are highly valued among mineral waters for their healing effects. Between 2005 and 2015, a large exploratory event for prospecting and documenting radon water springs ...took place in the crystalline area of Lugicum (Bohemian Massif) under Czech–Polish cooperation. For these purposes, an exploration method was developed as a combination of GIS (ArcMap 9.1–10.2) area preparation followed by field radiohydrogeochemical mapping at a scale of 1:10,000. The gamma indication method was optimized and used for the selection of water samples. A total of 2354 water sources were examined. Radon activity concentrations were measured at 660 sources found throughout the territory. Of those, 111 sources exhibited 222Rn activity above 1500 Bq/L and, thus, were categorized as sources of mineral radioactive waters according to Czech legislation. The highest 222Rn activity was found in the Michael spring near Nové Město pod Smrkem (up to 6237 Bq/L 222Rn). Many discovered sources with high balneological potential are significant and, therefore, are quickly becoming popular among the public.
Moldavites are tektites genetically related to the Ries impact structure, located in Central Europe, but the source materials and the processes related to the chemical fractionation of moldavites are ...not fully constrained. To further understand moldavite genesis, the Cu and Zn abundances and isotope compositions were measured in a suite of tektites from four different substrewn fields (South Bohemia, Moravia, Cheb Basin, Lusatia) and chemically diverse sediments from the surroundings of the Ries impact structure. Moldavites are slightly depleted in Zn (~10–20%) and distinctly depleted in Cu (>90%) relative to supposed sedimentary precursors. Moreover, the moldavites show a wide range in δ66Zn values between 1.7 and 3.7‰ (relative to JMC 3‐0749 Lyon) and δ65Cu values between 1.6 and 12.5‰ (relative to NIST SRM 976) and are thus enriched in heavy isotopes relative to their possible parent sedimentary sources (δ66Zn = −0.07 to +0.64‰; δ65Cu = −0.4 to +0.7‰). In particular, the Cheb Basin moldavites show some of the highest δ65Cu values (up to 12.5‰) ever observed in natural samples. The relative magnitude of isotope fractionation for Cu and Zn seen here is opposite to oxygen‐poor environments such as the Moon where Zn is significantly more isotopically fractionated than Cu. One possibility is that monovalent Cu diffuses faster than divalent Zn in the reduced melt and diffusion will not affect the extent of Zn isotope fractionation. These observations imply that the capability of forming a redox environment may aid in volatilizing some elements, accompanied by isotope fractionation, during the impact process. The greater extent of elemental depletion, coupled with isotope fractionation of more refractory Cu relative to Zn, may also hinge on the presence of carbonyl species of transition metals and electromagnetic charge, which could exist in the impact‐induced high‐velocity jet of vapor and melts.
Variscan, mantle-derived peridotites and associated pyroxenites occur as boudins in Moldanubian granulite near the town of Horní Bory in western Moravia. The peridotites consist of two ...compositionally distinct suites, one of Mg–lherzolite (Mg-number
=
89–91,
87Sr/
86Sr
=
0.7046–0.7068,
ε
Nd
=
+
4.1 to +
5.3), and another of Fe–dunite/wehrlite (Mg-number
=
83–88,
87Sr/
86Sr
=
0.7079–0.7087,
ε
Nd
=
−
2.8 to −
1.3). Modelling of Mg–Fe exchange between peridotite and Fe-rich melts reveals that the modal and chemical composition of the Fe–dunite/wehrlite suite can be produced by melt–rock reactions between lherzolite and SiO
2-undersaturated melts of basaltic composition at melt/rock ratios ranging from 0.3 to 2. In such a model, pyroxenites represent the crystalline product (±
trapped liquid) of melts migrating along conduits in peridotite. The Fe–dunite/wehrlite suite and pyroxenites are enriched in the LILE and depleted in the HFSE. The trace element and Sr–Nd isotopic compositions of Horní Bory peridotites and pyroxenites point to a significant component of crustal material in the invasive melts. The melt–rock reactions recorded in the Horní Bory ultramafic boudins are attributed to melt percolation in a mantle wedge above a Variscan subduction zone.
The precision of the measurement of the anisotropy of magnetic susceptibility (AMS) depends, in addition to other factors like accuracy of measurement of directional susceptibility and number of ...measuring directions, also on the orientation of the measuring design with respect to the specimen's anisotropy. The last factor can be characterized by rotatability coefficient of the measuring design. We investigated through mathematical modelling of measuring process the effect of the rotatability coefficient on the error in the determination of degree of AMS, shape factor and principal directions. The effect is conspicuous in strongly non-rotatable designs with low number of measuring directions. It decreases with increasing rotatability and with increasing number of measuring directions. In designs with high number of directions this effect is small, virtually negligible from the practical point of view.
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•Rotatability of design of measuring directions.•Rotatable designs; Error propagation.•Effect of rotatability degree on measuring precision.•Advantage of full rotatability design in case of low number designs.•Decreasing effect of rotatability with increasing number of measuring directions.
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