A compromise aspect-adaptive cylindrical projection for world maps

There are two problems with current cylindrical projections for world maps. First, existing cylindrical map projections have a static height-to-width aspect ratio and do not automatically adjust their aspect ratio in order to optimally use available canvas space. Second, many of the commonly used cylindrical compromise projections show areas and shapes at higher latitudes with considerable distortion. This article introduces a new compromise cylindrical map projection that adjusts the distribution of parallels to the aspect ratio of a canvas. The goal of designing this projection was to show land masses at central latitudes with a visually balanced appearance similar to how they appear on a globe. The projection was constructed using a visual design procedure where a series of graphically optimized projections was defined for a select number of aspect ratios. The visually designed projections were approximated by polynomial expressions that define a cylindrical projection for any height-to-width ratio between 0.3:1 and 1:1. The resulting equations for converting spherical to Cartesian coordinates require a small number of coefficients and are fast to execute. The presented aspect-adaptive cylindrical projection is well suited for digital maps embedded in web pages with responsive web design, as well as GIS applications where the size of the map canvas is unknown a priori. We highlight the projection with a height-to-width ratio of 0.6:1, which we call the Compact Miller projection because it is inspired by the Miller Cylindrical projection. Unlike the Miller Cylindrical projection, the Compact Miller projection has a smaller height-to-width ratio and shows the world with less areal distortion at higher latitudes. A user study with 448 participants verified that the Compact Miller – together with the Plate Carrée projection – is the most preferred cylindrical compromise projection.     

Global geological mapping of Ganymede

We have compiled a global geological map of Ganymede that represents the most recent understanding of the satellite based on Galileo mission results. This contribution builds on important previous accomplishments in the study of Ganymede utilizing Voyager data and incorporates the many new discoveries that were brought about by examination of Galileo data. We discuss the material properties of geological units defined utilizing a global mosaic of the surface with a nominal resolution of 1 km/pixel assembled by the USGS with the best available Voyager and Galileo regional coverage and high resolution imagery (100-200 m/pixel) of characteristic features and terrain types obtained by the Galileo spacecraft. We also use crater density measurements obtained from our mapping efforts to examine age relationships amongst the various defined units. These efforts have resulted in a more complete understanding of the major geological processes operating on Ganymede, especially the roles of cryovolcanic and tectonic processes in the formation of might materials. They have also clarified the characteristics of the geological units that comprise the satellite’s surface, the stratigraphic relationships of those geological units and structures, and the geological history inferred from those relationships. For instance, the characteristics and stratigraphic relationships of dark lineated material and reticulate material suggest they represent an intermediate stage between dark cratered material and light material units.     

The role of hybridization in the genesis of Hercynian granitodis in the gredos massif,Spain: inferences from Sr-Nd isotopes

The Gredos massif is one the better exposed granitoid complexes of the Iberian massif. It is composed mainly of peraluminous granitoids with subordinate basic and ultrabasic complexes. The massif also contains mega-enclaves of migmatites with which the granitoids show transitional contacts. Two major magmatic associations have been distinguished in this study: (1) One comprises the granitoids with microgranular enclaves, the enclaves, and basic rocks; (2) the other is formed by leucogranites, intrusive into the former series and free of microgranular enclaves. Field relationships and microstructures indicate that the rocks of the first series are related by a dominant hybridization process. The Sr-Nd isotopic study reveals that this process is complex, relating different end-members of mantle and crustal affinities, and occurred around 295 Ma ago, late with respect to the main deformation phases of the Hercynian orogeny. The granitoids with microgranular enclaves (GME) are part of an overall mixing trend involving Palaeozoic mantle-derived magma and melts of older crustal material. Amphibole-bearing GME, in general, contain greater proportions of the mantle-derived component than the cordierite-bearing GME. The actual mixing processes took place on a variety of scales, sometimes between melts which were themselves hybrids. On a local scale this hybridization process can be modelled by simple binary mixing as documented in the case of a composite dyke. The isotopic signatures of the basic rocks are probably, to a large degree, the result of interaction with crustal melts, though additionally the presence of an enriched mantle source cannot be elmininated. Microgranular enclaves and their immediate hosts have differing initial Sr and Nd isotopic signatures, indicating that isotopic equilibrium was not attained. This suggests that the enclaves did not reside in their final granitic melt for long before cooling of the whole system. The enclaves are considered to have been derived from basaltic melts which had fractionated and hybridised to varying degrees. Late-stage peraluminous leucogranites have similar initial Nd isotopic compositions to the evolved GME; a crustal source with a radically different Nd isotopic composition or age does not need to be invoked in their petrogenesis.     

The circumvention of the natural biopurification of calcium along nutrient pathways by atmospheric inputs of industrial lead

Biopurification factors for Ca with respect to Sr, Ba, and natural, uncontaminated Pb were measured for different nutrient-consumer pairs in a remote subalpine ecosystem. The factor for Sr is expressed as: (nutrient $\text{Sr}\text{Ca}$) ÷ (consumer $\text{Sr}\text{Ca}$). Similar expressions were used for $\text{Ba}\text{Ca}$ and $\text{Pb}\text{Ca}$. It was found that Ca was biopurified of Sr 3-fold, of Ba 16-fold, and of Pb 100-fold in going from rock to sedge leaves. In going from sedge leaf to vole, Ca was biopurified of Sr 4-fold, of Ba 8-fold, and of Pb 16-fold. In going from meadow vole to pine marten, Ca was biopurified of Sr 6-fold, of Ba 7-fold, and of Pb 1.1-fold. Similar ranges of values for these factors were obtained for detrital and amphibian food chains. Fluxes of industrial lead entering the ecosystem as precipitation and dry deposition were measured and it was found that 40% of the lead in soil humus and soil moisture, 82% of the lead in sedge leaves, 92% of the lead in vole, and 97% of the lead in marten was industrial. The natural skeletal $\text{Pb}\text{Ca}$ ratio in carnivores (4 × 10^?8) was determined by means of corrections for inputs of industrial lead, food chain relationships, and measured biopurification factors for the ecosystem studied. This represents a 1700-fold reduction of the average $\text{Pb}\text{Ca}$ ratio in igneous rocks at the earth's surface (6.4 × 10^?5) by the compounding of successive Pb biopurification factors in transferring Ca from rock to carnivore. The natural ratio is similar to the value of 6 × 10^?8 observed for $\text{Pb}\text{Ca}$ in the bones of Peruvians who lived 2000 years ago but is 1/900th of the value of about 3.5 × 10^?5 for the skeletal $\text{Pb}\text{Ca}$ ratio found in present day Americans.This study shows experimentally how the $\text{Ba}\text{Ca}$ ratio in average surface igneous rock (3 × 10^?3) has been reduced 800-fold through compounding of successive biopurification steps to provide the skeletal $\text{Ba}\text{Ca}$ ratio of about 4 × 10^?6 observed in humans. It also provides biopurification factors for Sr and Ba among a number of nutrient-consumer pairs which anthropologists can use to delineate degrees of herbivory in diets of hominids within the last 10,000 years.     

Late Holocene sea-level changes and isostatic crustal movements in Atlantic Canada

It has long been recognised that sea levels along the shores of Atlantic Canada have been rising rapidly during the Holocene in response to isostatic crustal movements. New sea-level data for the Bay of Fundy coast of southern New Brunswick (Little Dipper Harbour) and the Atlantic coast of Nova Scotia (Chezzetcook Inlet) show that late Holocene average rates of sea-level rise in these areas have been 1.0 and 2.5 m per 1000 yr, respectively. Numerical model calculations suggest that the high rates of sea-level rise are due to crustal subsidence produced by the combined effects of Laurentide ice loading (forebulge collapse) and ocean loading of the Scotian shelf. Although ice loading is the dominant contributor to the regional sea-level pattern, ocean loading is also important, contributing up to 40% of the total crustal subsidence in some areas. Tide gauges record rates of sea-level rise during the 20^th century that are 0.7–1.9 mm/yr higher than late Holocene trends, with the highest residuals occurring in the Bay of Fundy.     

Sensitivity and cost considerations for the detection and eradication of marine pests in ports

Port surveys are being conducted in Australia, New Zealand and around the world to confirm the presence or absence of particular marine pests. The most critical aspect of these surveys is their sensitivity-the probability that they will correctly identify a species as present if indeed it is present. This is not, however, adequately addressed in the relevant national and international standards. Simple calculations show that the sensitivity of port survey methods is closely related to their encounter rate-the average number of target individuals expected to be detected by the method. The encounter rate (which reflects any difference in relative pest density), divided by the cost of the method, provides one way to compare the cost-effectiveness of different survey methods. The most cost-effective survey method is site- and species-specific but, in general, will involve sampling from the habitat with the highest expected population of target individuals. A case study of Perna viridis in Trinity Inlet, Cairns, demonstrates that plankton trawls processed with gene probes provide the same level of sensitivity for a fraction of the cost associated with the next best available method-snorkel transects in bad visibility (secchi depth=0.72 m). Visibility and the adult/larvae ratio, however, are critical to these arguments. If visibility were good (secchi depth=10 m), the two approaches would be comparable. Diver deployed quadrats were at least three orders of magnitude less cost-effective in this case study. It is very important that environmental managers and scientists perform sensitivity calculations before embarking on port surveys to ensure the highest level of sensitivity is achieved for any given budget.     

Organic matter degradation in paper sludge amendments over gold mine tailings

The long-term stability of paper sludge amendments as covers for reclaimed mine waste storage facilities must be assessed by the mining industry. This study examines a 6 yr old sequence of paper sludge amendments applied over wastes from historic Au mines located in Northern Ontario, Canada. As paper sludge is mostly comprised of C-rich organic compounds, elemental quantification, ¹³C cross polarization/magic angle spinning nuclear magnetic resonance (¹³C CP/MAS NMR) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to examine the minimal changes in the C content and speciation observed of the amendments over time. These results suggest that paper sludge covers are suitable for use in medium to long-term mining reclamation strategies.