Apollo 15 green glasses

Apollo 15 breccia 15427 and soils 15101, 15261 and 15301 contain abundant spheres and fragments of a green glass that is remarkably constant in composition. The glass is rich in Fe and Mg, and low in Ti, unlike any known lunar basalt, and may be derived from material of pyroxenitic composition in the Apennine Front.     

A lunar rock of deep crustal origin: sample 76535

Lunar sample 76535 is a coarse-grained troctolitic granulite exhibiting a texture indicative of long annealing times. It is composed of homogeneous crystals of plagioclase (58 per cent, An₉₆), olivine (37 per cent, Fo₈₈) and bronzite (4 per cent, En₈₆).Chromian spinel-bronzite-diopside (Wo₄₆En₅₀Fs₄) symplectic intergrowths commonly occur along olivine-plagioclase boundaries and as tiny inclusions within olivine grains. These symplectites apparently formed by a reaction of the type:

$\text{OI + An + Chromite → Opx + Cpx + Al-Mg-chromite}$

. The reaction is related to the experimentally determined reaction

$\text{OI + An = Opx + Cpx + Sp}$

of Kushiro and Yoder (1966). The enstatite content of the diopside coexisting with the bronzite indicates equilibration at about 1000°C. Thermodynamic calculations for 1000°C indicate that the symplectites formed at a minimum pressure of about 0.6 kb. Low alumina contents of the pyroxenes indicate equilibration near this minimum pressure.Clusters of the same assemblage found in the symplectic intergrowths, but containing accessory metal, troilite, Ca-phosphates, baddeleyite, plagioclase and/or K-feldspar occur sporadically throughout the rock. These apparent late stage products crystallized in the low temperature-high pressure region discussed above.Phase relations of co-existing metal phases indicate that the rock cooled at a few tens of degrees/my, corresponding to depths of 10–20 km below the lunar surface, in agreement with the above pressure estimate.We infer that 76535 represents an original cumulate deposited at a depth between about 10 and 30 km. The last liquid crystallized in the relatively high pressure-low temperature field opx + cpx + Al-Mg-chromite. Cooling was extremely slow and accompanied by extensive chemical and textural re-equilibration. Reaction to form the symplectites occurred during the late stages of re-equilibration.     

O/O mapping and hydrogeology of a short-lived (≈10 years) fumarolic (>500°C) meteoric–hydrothermal event in the upper part of the 0.76 Ma Bishop Tuff outflow sheet, California

¹⁸O/¹⁶O data from the 200-m-thick, 0.76 Ma Bishop Tuff outflow sheet provide evidence for a vigorous, short-lived (≈10 years), high-temperature, fumarolic meteoric–hydrothermal event. This is proved by: (1) the juxtaposition in the upper, partially welded Bishop Tuff of low-¹⁸O groundmass/glass (δ¹⁸O=−5 to +3) with coexisting quartz and feldspar phenocrysts having magmatic δ¹⁸O values (+8.7±0.3; +7.5±0.3); and (2) the fact that these kinds of ¹⁸O/¹⁶O signatures correlate very well with morphological features and mapped zones of fumarolic activity. Profiles of δ¹⁸O with depth in the Bishop Tuff within the fumarole area define a 40- to 50-m-thick, low-¹⁸O, stratigraphic zone that is sandwiched between the essentially unwelded near-surface portion of the tuff and an underlying, densely welded black tuff that displays magmatic ¹⁸O/¹⁶O values. Shallow-dipping columnar joints and other fumarolic features (i.e., subhorizontal tubular conduits and steep fissures) correlate very well with these pervasively devitrified, low-¹⁸O zones. The base of the low-¹⁸O zone is extremely sharp (3‰ per meter) and is located directly above the transition from partially welded tuff to densely welded black tuff. The observed average whole-rock ¹⁸O-depletions within this low-¹⁸O zone are about 6–7‰, requiring meteoric water/rock ratios in excess of 0.24 in mass units. Rainfall on the surface of the tuff would not have been high enough to supply this much H₂O in the short lifetime of fumarolic activity, suggesting that some recharge must have been from groundwater flow through the upper part of the tuff, above the sloping (1°–5°) top of the impermeable lower zone. This is compatible with the observation that the fumarolic areas roughly correlate with the preeruptive regional drainage pattern. Some of this recharge may in part have been from the lake that filled Long Valley caldera, which was dammed by the Bishop Tuff up to the level of this boundary between the partially and densely welded zones (≈7000 ft, the elevation of the highest Long Valley Lake shorelines). Gazis et al. had previously shown that the 2.8-Ma intracaldera Chegem Tuff from the Caucasus Mountains exhibits exactly the same kind of ¹⁸O-signature that we have correlated with fossil fumaroles in the Bishop Tuff outflow sheet. Although not recognized as such by McConnell et al.; ¹⁸O/¹⁶O data from drill-hole samples from the intracaldera Bishop Tuff in Long Valley also display this characteristic ¹⁸O signature (i.e., analogous δ¹⁸O-depth profiles, as well as low-¹⁸O groundmass coexisting with high-¹⁸O feldspar phenocrysts). This fumarolic ¹⁸O/¹⁶O signature is observed to much greater depths (≈650–750 m) in the intracaldera tuffs (≈1500 m thick) than it is in the ≈200-m-thick Bishop Tuff outflow sheet (≈80 m depth).     

Urban Environmental Justice Indices

Environmental justice is the principle that environmental costs and amenities ought to be equitably distributed within society. Due to the ethical, political, and public–health implications, and because many choices confront those researching environmental justice, standardized measures are needed to inform public dialogue and policy. We develop and test seven indices on three Colorado cities to measure the relationship between the distribution of environmental hazards and minority and poverty–stricken populations, and recommend the Comparative Environmental Risk Index as a preliminary, standardized measure for comparing urban areas. This index is particularly relevant to disadvantaged communities, regional planning organizations, environmental–justice networks and scholars, and state and federal agencies.     

Circulation and Mixing of Water Masses of Tatar Strait and the Northwestern Boundary Region of the Japan Sea

The deep waters of the northern portions of the Japan Sea are examined. It is found that the flow regime south of the southern Tatar Strait region is generally cyclonic in the upper ocean, with only weak flows present below depths of a few hundred meters. The Japan Sea appears to be remarkably well-mixed below depths of a few hundred meters, both horizontally and vertically. Based on chlorofluorocarbon measurements, it is concluded that the deep waters of the Japan Sea have been only weakly ventilated in recent decades. Results from a simple box model suggest two possible scenarios for the ventilation of the Japan Sea since the 1930s. In the first scenario, deep ventilation of the Japan Sea was relatively weak, but constant, from the 1930s to the present, with a deep-water residence time of approximately 500 years. In the second scenario, ventilation was relatively vigorous through the mid-1960s, with a deep-water residence time of approximately 100 years; after the mid-1960s, the ventilation of the deep waters stopped. The model results are consistent with the idea that presently the ventilation of the deep water of the Japan Sea is weak or nonexistent. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genomic resources for the spotted ragged-tooth shark Carcharias taurus

Genomic data can be a useful tool in the management and conservation of biodiversity. Here, we report the development of genomic resources for the spotted ragged-tooth shark Carcharias taurus using genome-wide DNA data from Illumina next-generation sequencing. We explored two commonly used genetic marker types: microsatellites and mitochondrial DNA. A total of 4 394 putative microsatellites were identified, of which 10 were tested on 24 individuals and found to have ideal properties for population genetic analyses. Additionally, we reconstructed the first complete mitochondrial genome of a South African spotted ragged-tooth shark, and highlight the most informative gene regions to facilitate future primer design. The data reported here may serve as a resource for future studies and can ultimately be applied in the sustainable conservation and fisheries management of this apex predator.