Eurekadumpite, (Cu,Zn)16(TeO3)2(AsO4)3Cl(OH)18·7H2O, a new supergene mineral species

A new mineral eurekadumpite found at the Centennial Eureka Mine in the Tintic district of Juab County in Utah in the United States occurs in the oxidation zone along with quartz, macalpineite, malachite, Zn-bearing olivenite, goethite, and Mn oxides. Eurekadumpite forms spherulites or rosettes up to 1 mm in size and their clusters and crusts up to 1.5 cm² in cavities. Its individuals are divergent and extremely thin (up to 0.5 mm across and less than 1 μm thick) hexagonal or roundish leaflets. The mineral is deep blue-green or turquoise-colored. Its streaks are light turquoise-colored. Its luster is satiny in aggregates and pearly on individual flakes. Its cleavage is (010) perfect and micalike. Its flakes are flexible but inelastic. Its Mohs hardness is 2.5–3.0, and D(meas) = 3.76(2) and D(calc) = 3.826 g/cm³. The mineral is optically biaxial negative, and α = 1.69(1), β ∼ γ = 1.775(5), and 2V _meas = 10(5)°. Its pleochroism is strong: Y = Z = deep blue-green, and X = light turquoise-colored. Its orientation is X = b. The wavenumbers of the bands in the IR spectrum (cm⁻¹; the strong lines are underlined, and w denotes the weak bands) are 3400, 2990, 1980w, 1628, 1373w, 1077, 1010, 860, 825, 803, 721w, 668, 622, 528, 461. The IR spectrum shows the occurrence of the tellurite (Te⁴⁺,O₃)²⁻ and arsenate (As⁵⁺,O₄)³⁻ anionic groups and H₂O molecules; Cu and Zn cations are combined with OH⁻ groups. The chemical composition of eurekadumpite is as follows (wt %, average of 14 electron-microprobe analyses; H₂O determined using the Alimarin method): 0.04 FeO, 36.07 CuO, 20.92 ZnO, 14.02 TeO₂, 14.97 As₂O₅, 1.45 Cl, 13.1 H₂O, O = Cl₂ −0.33, total 100.24. The empirical formula based on 2 Te atoms is (Cu_10.32Zn_5.85Fe_0.01)_Σ16.18(TeO₃)₂(AsO₄)_2.97[Cl_0.93(OH)_0.07]_Σ1(OH)_18.45 · 7.29H₂O. The idealized formula is (Cu,Zn)₁₆(TeO₃)₂(AsO₄)₃Cl(OH)₁₈ · 7H₂O. Eurekadumpite is monoclinic (pseudohexagonal), and the most probable space groups are P2/m, P2, or Pm. The unit-cell parameters refined from the powder X-ray data are as follows: a = 8.28(3), b = 18.97(2), c = 7.38(2) ?, β = 121.3(6)°, V = 990(6) ?³, and Z = 1. The strongest reflections of the X-ray powder pattern (d, ? (I) [hkl]) are as follows: 18.92(100) [010], 9.45(19) [020], 4.111(13) [[`2]\bar 2 01], 3.777(24) [050, [`2]\bar 2 21, 041], 2.692(15) [[`3]\bar 3 11, 151, [`3]\bar 3 02], 2.524(41)[170, [`2]\bar 2 52, [`1]\bar 1 71], 1.558(22) [[`4]\bar 4 82, [`3]\bar 3 .10.1, 024]. The name of the mineral means, firstly, that it was found in specimens from dumps of the Centennial Eureka Mine. In addition, it could mean found in a dump (the Greek word eureka means I have found it). There is an allusion to the great role that dumps of abandoned mines have played in the discovery of new minerals. Type specimens are deposited at the Fersman Mineralogical Museum of the Russian Academy of Sciences in Moscow, at the Smithsonian National Museum of Natural History in Washington, and at the American Museum of Natural History in New York.     

Responses of polar mesospheric cloud brightness to stratospheric gravity waves at the South Pole and Rothera,Antarctica

We present the first observational proof that polar mesospheric cloud (PMC) brightness responds to stratospheric gravity waves (GWs) differently at different latitudes by analyzing the Fe Boltzmann lidar data collected from the South Pole and Rothera (67.5°S, 68.0°W), Antarctica. Stratospheric GW strength is characterized by the root-mean-square (RMS) relative density perturbation in the 30–45 km region and PMC brightness is represented by the total backscatter coefficient (TBC) in austral summer from November to February. The linear correlation coefficient (LCC) between GW strength and PMC brightness is found to be +0.09 with a 42% confidence level at the South Pole and ?0.49 with a 98% confidence level at Rothera. If a PMC case potentially affected by a space shuttle exhaust plume is removed from the Rothera dataset, the negative correlation coefficient and confidence level increase to ?0.61 and 99%, respectively. The Rothera negative correlation increases when shorter-period waves are included while no change is observed in the South Pole correlation. Therefore, observations show statistically that Rothera PMC brightness is negatively correlated with the stratospheric GW strength but no significant correlation exists at the South Pole. A positive correlation of +0.74 with a confidence level of 99.98% is found within a distinct subset of the South Pole data but the rest of the dataset exhibits a random distribution, possibly indicating different populations of ice particles at the South Pole. Our data show that these two locations have similar GW strength and spectrum in the 30–45 km region during summer. The different responses of PMC brightness to GW perturbations are likely caused by the latitudinal differences in background temperatures in the ice crystal growth region between the PMC altitude and the mesopause. At Rothera, where temperatures in this region are relatively warm and supersaturations are not as large, GW-induced temperature perturbations can drive subsaturation in the warm phase. Thus, GWs can destroy growing ice crystals or limit their growth, leading to negative correlation at Rothera. Because the South Pole temperatures in the mesopause region are much colder, GW-perturbed temperature may never be above the frost point and have less of an impact on crystal growth and PMC brightness. The observed phenomena and proposed mechanisms above need to be understood and verified through future modeling of GW effects on PMC microphysics and ray modeling of GW propagation over the South Pole and Rothera.     

Sustainable urban drainage systems: examining the potential for green infrastructure-based stormwater management for Sub-Saharan cities

Green infrastructure (GI)-based approaches to urban drainage such as sustainable urban drainage systems (SUDS) could provide Sub-Saharan cities with an opportunity to address projected climate change impacts and existing deficits in their drainage infrastructure, even more so due to the synergies between an enhanced green infrastructure stock and sustainable urban development. The objective of this paper was to assess the theoretical value of using green infrastructure for stormwater management as an alternative and supplement to conventional pipe-based stormwater management systems. A SWOT analysis is performed to assess the potential that SUDS hold if adopted and implemented in Sub-Saharan cities. This analysis is based on a review of sustainable stormwater management as well as urban planning and governance literature. Results show that despite seemingly significant barriers to the adoption of SUDS in Sub-Saharan cities such as low prioritization on the urban agenda and lack of data among others, the concept may hold valuable potential for flood risk reduction, even more so due to its multi-functionality and synergies with urban agriculture, amenity and water supply. In the light of the existing threats and weaknesses, it is recommended that GI-based SUDS may be best approached initially as experiments at a local community scale.     

On the role of domain size and resolution in the simulations with the HIRHAM region climate model

We investigate the simulated temperature and precipitation of the HIRHAM regional climate model using systematic variations in domain size, resolution and detailed location in a total of eight simulations. HIRHAM was forced by ERA-Interim boundary data and the simulations focused on higher resolutions in the range of 5.5–12 km. HIRHAM outputs of seasonal precipitation and temperature were assessed by calculating distributed model errors against a higher resolution data set covering Denmark and a 0.25° resolution data set covering Europe. Furthermore the simulations were statistically tested against the Danish data set using bootstrap statistics. The results from the distributed validation of precipitation showed lower errors for the winter (DJF) season compared to the spring (MAM), fall (SON) and, in particular, summer (JJA) seasons for both validation data sets. For temperature, the pattern was in the opposite direction, with the lowest errors occurring for the JJA season. These seasonal patterns between precipitation and temperature are seen in the bootstrap analysis. It also showed that using a 4,000 × 2,800 km simulation with an 11 km resolution produced the highest significance levels. Also, the temperature errors were more highly significant than precipitation. In similarly sized domains, 12 of 16 combinations of variables, observation validation data and seasons showed better results for the highest resolution domain, but generally the most significant improvements were seen when varying the domain size.     

Faraday Rotation Response to Coronal Mass Ejection Structure

We present the results from modeling the coronal mass ejection (CME) properties that have an effect on the Faraday rotation (FR) signatures that may be measured with an imaging radio antenna array such as the Murchison Widefield Array (MWA). These include the magnetic flux rope orientation, handedness, magnetic-field magnitude, velocity, radius, expansion rate, electron density, and the presence of a shock/sheath region. We find that simultaneous multiple radio source observations (FR imaging) can be used to uniquely determine the orientation of the magnetic field in a CME, increase the advance warning time on the geoeffectiveness of a CME by an order of magnitude from the warning time possible from in-situ observations at L ₁, and investigate the extent and structure of the shock/sheath region at the leading edge of fast CMEs. The magnetic field of the heliosphere is largely “invisible” with only a fraction of the interplanetary magnetic-field lines convecting past the Earth; remote sensing the heliospheric magnetic field through FR imaging from the MWA will advance solar physics investigations into CME evolution and dynamics.     

Methodology and exploration for sandstone-type uranium deposits

Mobility of uranium with ground water in near surface earth conditions and its association with sandstone formations of continental depositional environments require an increase in the understanding and application of depositional characteristics in exploration. This paper, therefore, summarizes significant relationships of uranium geochemistry in the supergene environments and depositional characteristics of fluvial, deltaic, and lacustrine environments and their influence on exploration that may aid in the expeditious search for sandstone-type uranium deposits throughout the world.     

Zur Spur-für Spur-Korrektur in der Seismik

Zusammenfassung Der nachfolgende Aufsatz diskutiert erneut die Frage der Korrekturen bei der Auswertung seismischer Filme. Die vom Verfasser vorgeschlagene Methode ist auf alle Verfahren der angewandten Seismik anwendbar und kann zur Entlastung des Wissenschaftlers von jedem Zeichner oder Rechner gehandhabt werden.

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Summary The following lines discuss anew the problem of the corrections while interpreting seismic records. The method recommended by the author applied to all methods of the applied seismics and can be performed by any drawer or calculator in order to relieve the scientist.

     

Atmospheric Disturbances that Generate Intermittent Turbulence in Nocturnal Boundary Layers

Using the unprecedented observational facilities deployed duringthe 1999 Cooperative Atmosphere-Surface Exchange Study (CASES-99),we found three distinct turbulent events on the night of 18October 1999. These events resulted from a density current,solitary wave, and internal gravity wave, respectively. Our studyfocuses on the turbulence intermittency generated by the solitarywave and internal gravity wave, and intermittent turbulenceepisodes associated with pressure change and wind direction shiftsadjacent to the ground. Both the solitary and internal gravitywaves propagated horizontally and downward. During the passage ofboth the solitary and internal gravity waves, local thermal andshear instabilities were generated as cold air was pushed abovewarm air and wind gusts reached to the ground. These thermal andshear instabilities triggered turbulent mixing events. Inaddition, strong vertical acceleration associated with thesolitary wave led to large non-hydrostatic pressure perturbationsthat were positively correlated with temperature. The directionaldifference between the propagation of the internal gravity waveand the ambient flow led to lateral rolls. These episodic studiesdemonstrate that non-local disturbances are responsible for localthermal and shear instabilities, leading to intermittentturbulence in nocturnal boundary layers. The origin of thesenon-local disturbances needs to be understood to improve mesoscalenumerical model performance.