Andrew U. Frank’s impact on research in land administration

Andrew U. Frank retired in October 2016 after a scientific career of 38 years with positions in Switzerland, Maine and Austria. One of the main applications that he constantly referred to and that he analysed in detail was land administration. This review article tries to give an overview of Frank’s work in the context of land administration and how he influenced the approach to land administration research. He organized his work mainly in four pillars: technical, legal, organizational and economical aspects. Each of them is discussed in the paper and the influence on international cooperation is shown.     

High-Pressure Melting of Eclogite and the P-T-X History of Tonalitic to Trondhjemitic Zoisite-Pegmatites, Munchberg Massif, Germany

Zoisite-bearing high-pressure pegmatites from the MünchbergMassif, Germany, provide an excellent example of the characteristicsof the onset of metabasite melting at eclogite-facies conditions.The pegmatites were derived by partial melting of a mid-oceanridge basalt (MORB)-like eclogite at T 680°C/2·3GPa to 750°C/3·1 GPa, which produced small amountsof tonalitic to trondhjemitic melt. The melt concentrated locallyin isolated, small melt pockets and crystallized primary zoisiteas liquidus phase at P 2·3 GPa/680°C to 2·1GPa/750°C. Compositional zoning of pegmatite zoisite recordsan ensuing multi-stage uplift history with successive, discretecrystallization events at 1·4 ± 0·2 GPa/650–700°Cand 1·0 ± 0·1 GPa/620–650°C.Resorption textures indicate reheating and thermal perturbationof the whole system prior to each successive crystallizationevent. Final solidification of zoisite-pegmatites occurred at0·9 ± 0·1 GPa/620–650°C. Thedata suggest that isolated melt + zoisite crystal mush pocketsformed an integral part of the eclogite throughout uplift frommelt formation at T 680°C/2·3 GPa to 750°C/3·1GPa to final solidification at 0·9 GPa/620–630°C;that is, over a depth range of 45–60 km. The entire pegmatite-formingprocess was probably fluid conserving: fluid present duringmelt formation was trapped by fully or nearly water-saturatedsiliceous melts, whereas fluid liberated during pegmatite crystallizationinteracted with dehydrated eclogite-facies assemblages to formamphibolite-facies hydrous minerals. A set of empirical D^{melt/eclogite}values based on mean zoisite-pegmatite and eclogite compositionwere used to model the onset of partial high-pressure meltingof metabasites. KEY WORDS: adakite; high-pressure melting; pegmatite; trondhjemite; zoisite     

Robust and fast reconstruction of complex roofs with active sampling from 3D point clouds

This article proposes a novel method for the 3D reconstruction of LoD2 buildings from LiDAR data. We propose an active sampling strategy which applies a cascade of filters focusing on promising samples at an early stage, thus avoiding the pitfalls of RANSAC‐based approaches. Filters are based on prior knowledge represented by (nonparametric) density distributions. In our approach samples are pairs of surflets—3D points together with normal vectors derived from a plane approximation of their neighborhood. Surflet pairs provide parameters for model candidates such as azimuth, inclination and ridge height, as well as parameters estimating internal precision and consistency. This provides a ranking of roof model candidates and leads to a small number of promising hypotheses. Building footprints are derived in a preprocessing step using machine learning methods, in particular support vector machines.     

Metal ion remediation by polyamidoamine dendrimers: a comparison of metal ion,oxidation state,and titania immobilization

The exceptional ability of dendrimers to coordinate metal ions yields the potential for many applications including wastewater remediation, which is the focus of this study. Here, the comparison of metal ion removal rate from simulated wastewater by generation 4 dendrimers with external hydroxyl functional groups (G4-OH) is evaluated for Ni²⁺, Fe²⁺, and Fe³⁺ ions. Ni²⁺ to amine complexation occurred more rapidly than Fe³⁺, which was more rapid than Fe²⁺ complexation. These results indicate that both charge density and d-electron configuration are important toward the chelation rate. The impact of both factors is discussed in light of existing models in which precursor aquation rates have been proposed as a key intermediate step. Additionally, the application of the dendrimers as chelation agents is further advanced by immobilizing the dendrimer to titania and re-evaluating its chelation ability for Ni²⁺ removal. The dendrimer immobilization decreased the pseudo-first-order rate coefficient for Ni²⁺—amine complexation at a pH of 7 by a factor of 7.5. This result is significant as it suggests that mass transfer becomes important following immobilization of the dendrimer to titania.     

Transformation of Aerosol Chemical Properties due to Transport Over a City

The change of the chemical composition of the near-ground level atmospheric aerosol was studied during two summer episodes by a Lagrangian type of experimental approach. Bulk and single-particle chemical analyses of ions and elements in the particulate phase were deployed. N(-III) and N(V) components were also measured in the gas-phase. The measurements were completed by particle size distributions.Secondary inorganic aerosols (SIA) and fine particles of ≈0.2–0.4 μm size were still elevated 50 km downwind of the city. The direct comparison of transport over the city in contrast to transport over the surrounding areas showed that SIA was formed from emission from the city within less than 3 h. Relative increases, i.e., enrichment during transport were observed for primary and secondary aerosol components. The degree of mixing on the individual particle level increased significantly during transport in the area. In particular, newly emitted carbonaceous particles became internally mixed within hours with pre-existing sulphate particles. Mostly due to secondary aerosol formation the average particle size (mass median diameter) of major constituents of the aerosol was significantly decreased while being transported over 13 h. Given recent insights which link fine particles number and mass concentrations with health risks, the results suggest that rural populations in areas which frequently are located within an urban plume might run an elevated health risk relative to populations in areas not affected by urban plumes.     

The Effect of the Canadian Shield on Cloud-to-Ground Lightning Density

The Canadian Shield is a large area of exposed bedrock that covers a significant portion of Canada. The focus of this research is on the Canadian Shield in northeastern regions of the Canadian Prairie provinces, the Northwest Territories, and northwestern Ontario. Observations of cloud-to-ground lightning flashes show a distinct reduction in lightning density when crossing the southern boundary of the Canadian Shield. Statistical tests were used to determine whether there was a statistically significant change between the average cloud-to-ground lightning density gradient near the Canadian Shield and away from it. Most regions had a statistically significant change at the 95% confidence level across the boundary. However, regions that contained large lakes or significant topography did not, suggesting that the large open water and rough topography have a greater effect than the Canadian Shield.

Three reasons for the distinct change across the Canadian Shield were explored: less lightning is detected, less lightning occurs with the same number of thunderstorms, and less lightning occurs because fewer thunderstorms occur. Some evidence suggested that less lightning is detected because the Canadian Shield has lower electrical conductivity. The low conductivity distorts the lightning waveform and contributes to higher errors and lower detection efficiency. There is also some evidence that a sharp change in land cover from lusher, higher transpiring forest to sparser lower transpiring forest could be reducing the instability causing fewer, weaker thunderstorms.     

Crustal contamination of mafic magmas: evidence from a petrological, geochemical and Sr–Nd–Os–O isotopic study of the Proterozoic Isortoq dike swarm, South Greenland

The mid-Proterozoic Isortoq dike swarm in the Gardar Province, South Greenland, comprises a variety of alkaline rocks ranging from gabbroic to syenitic in composition. Major magmatic mineral phases are olivine, clinopyroxene, Fe–Ti oxides, amphibole, plagioclase and alkali feldspar. Quartz occurs in some samples as a late magmatic phase. Liquidus temperatures of olivine-bearing samples range between 1120 and 1145 °C and solidus temperatures are 850–930 °C. Calculated silica activities are highly variable between 0.53 and unity. Oxygen fugacities vary from −3 to +1 log units relative to the fayalite–magnetite–quartz buffer.

The rocks have MgO contents <6 wt.% with Mg# between 53 and 17. Primitive mantle-normalized trace element patterns show a relative enrichment of LIL elements with Ba peaks and Nb troughs. Clinopyroxenes show a general enrichment in REE relative to chondritic values with variable slightly positive to prominent negative Eu anomalies. Two of the dikes were dated with Sm–Nd three-point isochrons at 1190±44 and 1187±87 Ma, respectively. Initial ⁸⁷Sr/⁸⁶Sr ratios of mafic mineral separates range from 0.70289 to 0.70432 and initial _Nd values vary from +0.3 to −10.7. Whole-rock initial ¹⁸⁷Os/¹⁸⁸Os ratios are highly variable including very radiogenic values of up to 7.967. δ¹⁸O_v-smow values of separated clinopyroxene and amphibole range from +5.2‰ to +6.2‰ and fall within the range of typical mantle-derived rocks, although mixing with a lower crustal component is permitted by the data. Using energy-constrained assimilation-fractional crystallization (EC-AFC) modeling equations, the Sr–Nd isotope data of the more radiogenic samples can successfully be modeled by addition of up to 10% lower crustal granulite-facies Archean gneisses as contaminants. The Os isotopic data also suggest the involvement of old radiogenic crust. In accordance with seismic data, we conclude that a wedge of Archean crust extends from West Greenland further to the south below the present erosion level.     

Determination of the Tin Stable Isotopic Composition in Tin‐bearing Metals and Minerals by MC‐ICP‐MS

This study uses MC‐ICP‐MS for the precise analysis of the stable tin isotopic composition in ore minerals of tin (cassiterite, stannite), tin metal and tin bronze. The ultimate goal is to determine the provenance of tin in ancient metal objects. We document the isotope compositions of reference materials and compare the precision of different isotope ratios and the accuracy of different procedures of mass fractionation correction. These data represent a base with which isotopic data of future studies can be directly compared. The isotopic composition of cassiterite and stannite can be determined after reduction to tin metal and bronze, respectively. Both metals readily dissolve in HCl, but while the solutions of tin metal can be directly measured, the bronze solutions must be purified with an anion exchanger. The correction of the mass bias is best performed with an internal Sb standard and an empirical regression method. A series of Sn isotope determinations on commercially available mono‐element Sn solutions as well as reference bronze materials and tin minerals show fractionations ranging from about ?0.09‰ to 0.05‰/amu. The combined analytical uncertainty (2s) was determined by replicate dissolutions of reference materials of bronze (BAM 211, IARM‐91D) and averages at about 0.005‰/amu.     

Cenozoic intra-plate magmatism in the Darfur volcanic province: mantle source, phonolite-trachyte genesis and relation to other volcanic provinces in NE Africa

Chemical and Sr, Nd and Pb isotopic compositions of Late Cenozoic to Quaternary small-volume phonolite, trachyte and related mafic rocks from the Darfur volcanic province/NW-Sudan have been investigated. Isotope signatures indicate variable but minor crustal contributions. Some phonolitic and trachytic rocks show the same isotopic composition as their primitive mantle-derived parents, and no crustal contributions are visible in the trace element patterns of these samples. The magmatic evolution of the evolved rocks is dominated by crystal fractionation. The Si-undersaturated strongly alkaline phonolite and the Si-saturated mildly alkaline trachyte can be modelled by fractionation of basanite and basalt, respectively. The suite of basanite–basalt–phonolite–trachyte with characteristic isotope signatures from the Darfur volcanic province fits the compositional features of other Cenozoic intra-plate magmatism scattered in North and Central Africa (e.g., Tibesti, Maghreb, Cameroon line), which evolved on a lithosphere that was reworked or formed during the Neoproterozoic.     

Systematics of internal zircon morphology in major Variscan granitoid types

The internal morphologies of zircon crystals from different types of granitoids (alkaline, calcalkaline and anatectic) are revealed by cathodoluminescence imaging and are described in terms of growth rates of the crystal faces relative to each other. Zircons in the alkaline granitoids are characterized by high and constant growth rates of {010} relative to the pyramidal forms and by symmetric grwoth of {011}. Zircons in the calcalkaline and anatectic granitoids are characterized by fluctuating or gradually decreasing relative growth rates of {010}, by asymmetric and highly variable growth of {011}, and by a tendency of {110} to become grwoth-inhibited. Corrosion events are interspersed during zircon growth in the calcalkaline magmas. In the calcalkaline and anatectic magmas, a discontinuity breaks the morphological evolution at late stages of crystallization. The discontinuity coincides with a sharp drop in cathodoluminescence. The growth behaviour of each crystal form is analysed and compared with predictions made by the periodic bond chain (PBC) theory. It is argued that the relative growth rate of {010} depends on supersaturation, that the growth rates of {011} faces are changed in response to different ratios of adsorbing cations (Na, K, Al), and that {110} faces become growth-inhibited by the adsorption of H₂O or trace elements enriched in the residual liquid. Morphological and chemical discontinuities at late stages of crystallization are reasonably explained by the formation of larger growth units (from smaller ionic entities) in the residual liquid. Important factors controlling the zircon morphology in different types of granitoids are: high cooling rates (alkaline magmas), magma mixing (calcalkaline magmas), enrichment of H₂O and trace elements in residual liquids (calcalkaline and anatectic magmas), and the major element chemistry of the magma, possibly the ratio of Na and K to Al (agpaicity).