Sequence of magma emplacement and sulfide saturation in the Gaojiacun–Lengshuiqing intrusive complex (SW China)

The Lengshuiqing area contains several small intrusions made up of peridotite ± quartz diorite ± granite spatially associated with the Gaojiacun pluton (gabbroids + peridotite + diorite). Ni–Cu sulfide ore occur at Lengshuiqing, hosted in peridotite. SHRIMP U–Pb zircon dating produced the ages of 803 ± 4.2 Ma (peridotite), 807 ± 2.6 Ma (oikocrystic hornblende gabbro), 809 ± 4.3 Ma (hornblende gabbronorites) for the Gaojiacun pluton and 807 ± 3.8 Ma (diorite, intrusion I), 817 ± 6.3 Ma (quartz diorite, intrusion II) and 817 ± 5 Ma (peridotite, intrusion 101) for Lengshuiqing. These ages suggest the emplacement of the Gaojiacun pluton later than the intrusions from Lengshuiqing. The olivine from Lengshuiqing does not contain sulfide inclusions and is relatively Ni-rich (1,150–1,550 ppm Ni), suggesting its crystallisation before the sulfide saturation that generated the Ni–Cu deposits. The olivine of the gabbros in the Gaojiacun pluton is Ni-poor (250–800 ppm), which indicates crystallisation from a severely metal-depleted magma after a sulfide saturation event. The olivine in the peridotites from the Gaojiacun pluton has 800–1,150 ppm Ni and contains sulfide inclusions. Moreover, geological evidence suggests the genesis of the peridotites from Gaojiacun in conduits that were ascending through the gabbroids. A sequence of at least three stages of magma emplacement is proposed: (1) Lengshuiqing; (2) gabbroids from Gaojiacun; (3) peridotites from Gaojiacun. Given the age differences, the intrusions at Lengshuiqing and the Gaojiacun pluton might have been produced by different magmatic events.     

Reported sulfate mineral in lunar meteorite PCA 02007 is impact glass

A grain of light‐blue sulfate material was reported in the lunar highlands regolith meteorite PCA 02007 (Satterwhite and Righter 2013). Allocated grains of that material are, in fact, aluminosilicate glass with a chemical composition like that of the bulk meteorite and other lunar highlands regoliths. The calcium sulfate detected in PCA 02007 was likely a surface coating, and reasonably of Antarctic (not lunar) origin.     

A protocol standard for heterogeneous telescope networks

The scientific need for a standard protocol permitting the exchange of generic observing services is rapidly escalating as more observatories adopt service observing as a standard operating mode and as more remote or robotic telescopes are brought on‐line. To respond to this need, we present the results of the first interoperability workshop for Heterogeneous Telescope Networks (HTN) held in Exeter. We present a draft protocol, designed to be independent of the specific instrumentation and software that controls the remote and/or robotic telescopes, allowing these telescopes to appear to the user with a unified interface despite any underlying architectural differences. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Plasmatrough ion mass densities determined from ULF pulsation eigenperiods

Auroral radar studies of ULF pulsations have proved useful in determining the spatial characteristics of resonant oscillations. A particular class of ringing or transient pulsations has been identified in the radar data as toroidal mode eigenoscillations. We have considered a total of 64 events of this type recorded by either the STARE radar in Scandinavia, or the Slope Point radar in New Zealand, giving a combined latitudinal coverage of approx. 12°. These events are interpreted as toroidal mode eigenoscillations; the periods for individual events and the mean periods increase with geomagnetic latitude. Use of hydromagnetic resonance theory allows the equatorial ion mass density to be determined. The densities obtained are appropriate to the plasmatrough and range from ～ 10 to 100 a.m.u. cm^?3 near geosynchronous orbit. The radial variation in the equatorial plane is typically R^?5 in the midnight-noon sector and R^?3 in the noon-midnight sector. To reconcile these pulsation periods with in situ electron density measurements implies that H⁺ ion densities in the range ～ 1–10 cm^?3 and ～50% O⁺ ions are required.     

Contrast in the isotopic composition of oxygen and carbon between the Mud Tank Carbonatite and the marbles in the granulite terrane of the Strangways Range,central Australia

Three samples from the Mud Tank Carbonatite have very similar isotopic ratios, averaging δ¹³C=‐4.3 and δ¹⁸O=+7.5(SMOW). These isotope values are distinct from those of nearby highly metamorphosed Carpentarian marbles, which have marine limestone values of δ¹³C=‐1.3±0.5, and δ¹⁸O=+17.6+0.7 with n=11. Minor variations in the values for the normal marbles show no correlation with stratigraphy or geographic location; however, somewhat lighter oxygen is found in some other marbles known to be affected by low‐temperature fluids within the Woolanga Lineament. Isotopes of C and O, if discretely used in conjunction with other geochemical features, not only may discriminate between deep‐seated carbona‐tites and marbles, but may also help to identify zones of carbonate metasomatism and define the isotopic characters of the fluids.     

Mercury,Trace Elements and Organic Constituents in Atmospheric Fine Particulate Matter,Shenandoah National Park,Virginia, USA: A Combined Approach to Sampling and Analysis

Compliance with U.S. air quality regulatory standards for atmospheric fine particulate matter (PM_2.5) is based on meeting average 24 hour (35 μ m^?3) and yearly (15 μg m^?3) mass‐per‐unit‐volume limits, regardless of PM_2.5 composition. Whereas this presents a workable regulatory framework, information on particle composition is needed to assess the fate and transport of PM_2.5 and determine potential environmental/human health impacts. To address these important non‐regulatory issues an integrated approach is generally used that includes (1) field sampling of atmospheric particulate matter on filter media, using a size‐limiting cyclone, or with no particle‐size limitation; and (2) chemical extraction of exposed filters and analysis of separate particulate‐bound fractions for total mercury, trace elements and organic constituents, utilising different USGS laboratories optimised for quantitative analysis of these substances. This combination of sampling and analysis allowed for a more detailed interpretation of PM_2.5 sources and potential effects, compared to measurements of PM_2.5 abundance alone. Results obtained using this combined approach are presented for a 2006 air sampling campaign in Shenandoah National Park (Virginia, USA) to assess sources of atmospheric contaminants and their potential impact on air quality in the Park. PM_2.5 was collected at two sampling sites (Big Meadows and Pinnacles) separated by 13.6 km. At both sites, element concentrations in PM₂₅ were low, consistent with remote or rural locations. However, element/Zr crustal abundance enrichment factors greater than 10, indicating anthropogenic input, were found for Hg, Se, S, Sb, Cd, Pb, Mo, Zn and Cu, listed in decreasing order of enrichment. Principal component analysis showed that four element associations accounted for 84% of the PM_2.5 trace element variation; these associations are interpreted to represent: (1) crustal sources (Al, REE); (2) coal combustion (Se, Sb), (3) metal production and/or mobile sources (Mo, Cd, Pb, Cu, Zn) and (4) a transient marine source (Sr, Mg). Concentrations of Hg in PM_2.5 at background levels in the single pg m^?3 were shown by collection and analysis of PM_2.5 on filters and by an automated speciation analyser set up at the Big Meadows air quality site. The speciation unit revealed periodic elevation of reactive gaseous mercury (RGM) that co‐occurred with peaks in SO₂, indicating an anthropogenic source. GC/MS total ion current chromatograms for the two sites were quite similar indicating that organic signatures were regional in extent and/or that the same compounds were present locally at each site. Calculated carbon preference index values for n‐alkanes indicated that plant waxes rather than anthropogenic sources, were the dominant alkane source. Polycyclic aromatic hydrocarbons (PAHs) were detected, with a predominance of non‐alkylated, and higher molecular weight PAHs in this fraction, suggestive of a combustion source (fossil fuel or forest fires).