Metamorphic feldspathization of metavolcanics and granitoids,Avnik area,Turkey

In the Avnik area of the Bingöl massif the Lower Unit consists of basic to felsic metavolcanics (ca. 450 Ma), intruded by granitoids (ca. 350 Ma). These are unconformably overlain by an Upper Unit of micaschists and Permian marbles; both units have been deformed and metamorphosed in Alpine time. The metavolcanics and granitoids are extensively feldspathized and silicified. The granitoids, and basic-intermediate volcanics, are albitized, while felsic volcanics are K-feldspathized. Metasomatism has severely modified K/Rb and Rb/Sr ratios, but not REE patterns, and is inferred to have occurred at relatively low T. Nametasomatism of the Upper Unit micaschists has produced albite porphyroblasts. Metasomatism postdates formation of the Upper Unit sediments, and is probably related to reaction with sea water that infiltrated the basement of volcanics and granitoids during deposition of these sediments. Rb-Sr whole-rock dating of extensively feldspathized intermediate-felsic metavolcanics gives an age of ca. 90 Ma, which suggests that the most extensive reaction coincided with expulsion of the trapped sea water during the early stages of the Alpine orogeny. The distribution of albitization vs. K-felds-pathization suggests that the type of metasomatism was controlled on a local scale by permeability and grain size, rather than by T variations.     

The upper Jovian atmosphere aerosol content determined from a satellite eclipse observation

The Galilean satellite eclipse technique for measuring the aerosol distribution in the upper Jovian atmosphere is described and applied using 30 color observations of the 13 May 1972 eclipse of Ganymede obtained with the 5-m Hale telescope. This event probes the South Temperate Zone. The observed aerosol lies above the visible cloud tops, is very tenuous and varies with altitude, increasing rapidly with downward passage through the tropopause. The aerosol extinction coefficient, κ_a (λ1.05 μm), is ～1.1 × 10^?9 cm^?1 in the lower stratosphere and ～1.1 × 10^?8 cm^?1 at the tropopause. The 1σ uncertainty in these values does not exceed 50% The observations require some aerosol above the tropopause but do not clearly determine its structure. The present analysis emphasizes an extended haze distribution, but the alternate possibility is not excluded that the stratospheric aerosol resides in a thin layer. The aerosol extinction increases with decreasing wavelength and indicates the particle radius to be ?0.2 μm. Larger radii are impossible. These overall results confirm Axel's (1972) suggestion of a small quantity of dust above the Jovian cloud tops and the optical depths are consistent with those required to explain the low uv albedo.     

Factors Influencing Adoption and Implementation of Conservation Development Ordinances in Rural United States

Conservation Development (CD) is a land-use tool to reduce the impacts of development on natural resources, yetthe use of CD is highly variable. We used a collaborative conservation model to examine factors influencing adoption and implementation to improve the future application of CD. We interviewed 2–3 individuals including planners, board members, and developers (n?=?46) from 16 rural communities in the intermountain west and northeast U.S. Motivations to preserve rural character or comply with state statutes drove adoption. Greater capacity such as outside expertise, model regulations, and iterative revisions of ordinances was associated with stronger ordinances. Adoption processes including ample dialog across diverse constituents, especially those overseeing subdivision development, facilitated higher rates of implementation. Concerns over open space management, lack of successful CD examples, and inexperience with CD posed barriers to implementation. Understanding social context revealed the strengths and shortcomings of CD and provided guidance for strategically engaging communities in private lands conservation.     

Suspended sediment in rapid subsurface stormflow on a large field plot

The occurrence of rapid movement of suspended sediment in subsurface stormflow on a large field plot in California is described. Concentrations of over 1000mgl^?1 were recorded in storms of only low to moderate intensity. The observed sediment was composed of uniformly fine-sized particles 4 to 8 μm in diameter. The mode of transport seems different from processes previously reported. Differences in sediment concentrations in different events, levels of ¹³⁷Cs on the sediment, and several other types of evidence indicate that the sediment was detached and entrained at the ground surface by raindrop impact and that the water and sediment flow occurred mainly through macropores in the soil. As conditions similar to those at the study site are not uncommon, it seems probable that the phenomenon may occur in many regions.     

A spectroscopic orbit for HD 115968

Photoelectric radial-velocity measurements show that the eighth-magnitude star HD 115968 is a spectroscopic binary with a period of 16.195 days. The star has a large proper motion, and is unlikely to have the luminosity corresponding to the spectral type of G8 III favoured by Zaitseva. It is most probably a late-G dwarf.