Fluorine in lunar samples: implications concerning lunar fluorapatite

The F contents of a number of Apollo 14 and 15 samples range from less than a ppm for anorthosite rock fragments to ~165 ppm for some soils and breccias. Apollo 15 soils tend to have lower F contents (50–70 ppm) than soils from other sites. In most cases samples were run simultaneously with W-1 in which F was determined to be 216 (±11) ppm.The $\text{F}\text{P}{}_2\text{O}{}_5$ ratio is 0·032 ± 0·005 in soils and rocks. A correlation exists in soils between F, P₂O₅, and that fraction of the Cl which is insoluble in hot water. The $\text{F}\text{Cl}{}_{\mathrm{r}}$ ratio in soils and rocks, though different, requires that the phosphate phase involved be fluorapatite; this is consistent with mineralogical observations. F, like Cl, is correlated with KREEP elements at all sites for which data are available.     

Assessing Possible Impacts of Climate Change on Species Important for Forestry in Vietnam

The likely effects on two tree species of a range of scenarios of climatic and atmospheric change expected by the year 2050 are investigated using a climatic mapping program, a simple simulation model and a process-based simulation model. Styrax tonkinensis is a native species for which relatively little information is available. Acacia mangium is an introduced species, which is important for pulp production in several other countries, and for which there is considerable information for growth and utilization. A climatic mapping program is used to show areas which may be suitable for these species under present and predicted conditions. Two simulation models are used to investigate likely effects on productivity of the two species for a range of climatic change scenarios for Hanoi and Ho Chi Minh City. The estimated changes in production are predicted to be relatively small, though uncertainities associated with the simulations are quite high. However, the models highlight areas where more data are needed and also suggest some key regions in Vietnam which would be worth monitoring to detect early signs of the effects of climatic and atmospheric change.     

Autonomous optical navigation using nanosatellite-class instruments: a Mars approach case study

This paper examines the effectiveness of small star trackers for orbital estimation. Autonomous optical navigation has been used for some time to provide local estimates of orbital parameters during close approach to celestial bodies. These techniques have been used extensively on spacecraft dating back to the Voyager missions, but often rely on long exposures and large instrument apertures. Using a hyperbolic Mars approach as a reference mission, we present an EKF-based navigation filter suitable for nanosatellite missions. Observations of Mars and its moons allow the estimator to correct initial errors in both position and velocity. Our results show that nanosatellite-class star trackers can produce good quality navigation solutions with low position (\(<300\,\text {m}\)) and velocity (\(<0.15\,\text {m/s}\)) errors as the spacecraft approaches periapse.     

Spatial variability of E. coli in an urban salt-wedge estuary

This study investigated the spatial variability of a common faecal indicator organism, Escherichia coli, in an urban salt-wedge estuary in Melbourne, Australia. Data were collected through comprehensive depth profiling in the water column at four sites and included measurements of temperature, salinity, pH, dissolved oxygen, turbidity, and E. coli concentrations. Vertical variability of E. coli was closely related to the salt-wedge dynamics; in the presence of a salt-wedge, there was a significant decrease in E. coli concentrations with depth. Transverse variability was low and was most likely dwarfed by the analytical uncertainties of E. coli measurements. Longitudinal variability was also low, potentially reflecting minimal die-off, settling, and additional inputs entering along the estuary. These results were supported by a simple mixing model that predicted E. coli concentrations based on salinity measurements. Additionally, an assessment of a sentinel monitoring station suggested routine monitoring locations may produce conservative estimates of E. coli concentrations in stratified estuaries.     

A high-quality monthly total cloud amount dataset for Australia

A high-quality monthly total cloud amount dataset for 165 stations has been developed for monitoring and assessing long-term trends in cloud cover over Australia. The dataset is based on visual 9 a.m. and 3 p.m. observations of total cloud amount, with most records starting around 1957. The quality control process involved examination of historical station metadata, together with an objective statistical test comparing candidate and reference cloud series. Individual cloud series were also compared against rainfall and diurnal temperature range series from the same site, and individual cloud series from neighboring sites. Adjustments for inhomogeneities caused by relocations and changes in observers were applied, as well as adjustments for biases caused by the shift to daylight saving time in the summer months. Analysis of these data reveals that the Australian mean annual total cloud amount is characterised by high year-to-year variability and shows a weak, statistically non-significant increase over the 1957–2007 period. A more pronounced, but also non-significant, decrease from 1977 to 2007 is evident. A strong positive correlation is found between all-Australian averages of cloud amount and rainfall, while a strong negative correlation is found between mean cloud amount and diurnal temperature range. Patterns of annual and seasonal trends in cloud amount are in general agreement with rainfall changes across Australia, however the high-quality cloud network is too coarse to fully capture topographic influences. Nevertheless, the broadscale consistency between patterns of cloud and rainfall variations indicates that the new total cloud amount dataset is able to adequately describe the broadscale patterns of change over Australia. Favourable simple comparisons between surface and satellite measures of cloudiness suggest that satellites may ultimately provide the means for monitoring long-term changes in cloud over Australia. However, due to the relative shortness and homogeneity problems of the satellite record, a robust network of surface cloud observations will be required for many years to come.     

First Permian–Early Triassic zircon ages for tin-bearing granites from the Gemeric unit (Western Carpathians, Slovakia): connection to the post-collisional extension of the Variscan orogen and S-type granite magmatism

This study presents the first preliminary U–Pb zircon data on tin-bearing S-type granites from the Gemeric unit of the Western Carpathians (Slovakia). U–Pb single zircon dating controlled by cathodoluminescence suggests crystallization of the Gemeric granites during Permian to Early Triassic (303–241 Ma) time. Post-crystallization, low-temperature metamorphic overprint is reflected by partial Pb loss in zircons. These Gemeric granites are younger than the highly fractionated, S-type, tin- and rare-element-bearing leucogranites in the European Variscides. They may have resulted from partial melting, triggered by increased heat flow from the mantle below the continental crust, and most probably intruded during the post-collisional extension and initial rifting of the Variscan orogenic belt. During Alpine orogeny, the Gemeric granites were affected by a low-temperature deformation and metamorphism.     

Characteristics of selenium migration in soil–plant system of East Meshchera and Transbaikalia

Herein some results of comparative researches to determine the parameters of selenium migration in meadow biogeocenoses of East Meshchera and East Transbaikalia are presented. The parameters of selenium mobility in soils (i.e., the element total content, plant-accumulation coefficient (Kb) and/or mobile form ratio) in Urov biogeochemical provinces of the East Transbaikalia are quite comparable to the element migration parameters found in selenium-deficient landscapes of the same area. Selenium mobility indices and ecological status are significantly higher for meadow biogeocenoses of the East Meshchera (Moscow Region) and also for limestone soils.     

Heavy element affinities in Apollo 17 samples

²⁰⁴Pb, Bi, Tl and Zn in samples from Apollo 17 exhibit relationships not found in samples from other sites.²⁰⁴Pb, Tl and Zn in residues remaining after dilute acid leaching are correlated with one another. Orange soil 74220, which is enriched in²⁰⁴Pb, Tl and Zn, is included in these relationships. In addition the submicron metallic phase generally associated with agglutinate formation is correlated with all three of these elements; this relationship has already been reported for²⁰⁴Pb in other samples. Thus, orange soil and agglutinates appear to be involved in concentrating heavy volatile metals. A process other than mixing is required to account for this. As a consequence of the isolation of the landing site by the surrounding massifs, local supply and recycling of volatile trace elements in soils may account for some of the interelement relations.     

Hg and Pt-metals in meteorite carbon-rich residues: suggestions for possible host phase for Hg

Carbon-rich and oxide residual phases have been isolated from Allende and Murchison by acid demineralization for the determination of their Hg, Pt-metal, Cr, Sc, Co and Fe contents. Experimental procedures used eliminated the possibility of exogenous and endogenous contaminant trace elements from coprecipitating with the residues. Large enrichments of Hg and Pt-metals were found in Allende but not in Murchison residues. Hg-release profiles from stepwise heating experiments suggest a sulfide as the host for Hg. Diffusion calculations for Hg based on these experiments indicate an activation energy of 7–8 kcal/mol, the same as that for Hg in troilite from an iron meteorite. This is further support for a sulfide host phase for Hg. Equilibration of Hg with this phase at ~900 K is indicated. Reasons why the Pt-metals are present in non-cosmic relative abundances are explored.