Potassic and low- and high-Ti mildly alkaline volcanism in the Neoproterozoic Ramada Plateau, southernmost Brazil

Ramada Plateau Neoproterozoic volcanism represents a portion of the shoshonitic and mildly alkaline magmatism related to postcollisional events of the Brasiliano/Pan African cycle of southernmost Brazil. It is constituted by shoshonitic basic-intermediate lavas, followed by a bimodal sequence characterized by pyroclastic deposits, lava flows, and hypabyssal rocks with ages of 549±5 Ma. The shoshonitic magmatism presents greater K₂O than Na₂O₂, K₂O/Na₂O ratios close to 1, and moderate large ion lithophile and high-field strength element contents. The bimodal basic-acid volcanism presents a transitional chemical affinity with features of sodic, silica-saturated alkaline to continental tholeiitic series. Observed basic and acid rocks with contrasting Ti contents are referred to as high- and low-Ti basalt-rhyolites. Another group of acid rocks with higher Nb, Ta, and Rb values was identified as high-Nb rhyolites. The Ramada Plateau magmatism is comparable to associations related to the final stages of orogenic cycles, in which shoshonitic and high- and low-Ti alkaline magmatism reflects the melting of subduction-modified sources, whereas the high-Nb magmas show less influence of subduction-related metasomatism and are closer to magmas produced from anorogenic sources. A model of magma generation in collisional settings involving slab break-off and asthenospheric upwelling is applied to the evolution of magmatism from subduction-related to anorogenic in the Ramada Plateau.     

Role of high-elevation groundwater flows in the hydrogeology of the Cimino volcano (central Italy) and possibilities to capture drinking water in a geogenically contaminated environment

Origin, yield and quality of the groundwater flows at high elevation in the Cimino volcano (central Italy) were examined. In this area, groundwater is geogenically contaminated by arsenic and fluoride, yet supplies drinking water for approximately 170,000 inhabitants. The origin of the high-elevation groundwater flows is strictly related to vertical and horizontal variability of the rock types (lava flows, lava domes and ignimbrite) in an area of limited size. In some cases, groundwater circuits are related to perched aquifers above noncontinuous aquitards; in other cases, they are due to flows in the highly fractured dome carapace, limited at the bottom by a low-permeability dome core. The high-elevation groundwater outflow represents about 30% of the total recharge of Cimino’s hydrogeological system, which has been estimated at 9.8 L/s/km². Bicarbonate alkaline-earth, cold, neutral waters with low salinity, and notably with low arsenic and fluoride content, distinguish the high-elevation groundwaters from those of the basal aquifer. Given the quantity and quality of these resources, approaches in the capture and management of groundwater in this hydrogeological environment should be reconsidered. Appropriate tapping methods such as horizontal drains, could more efficiently capture the high-elevation groundwater resources, as opposed to the waters currently pumped from the basal aquifer which often require dearsenification treatments.

     

Interpreting amenities,envisioning the future: common ground and conflict in North Carolina’s rural coastal communities

This paper contributes to ongoing discussions about the implications of rural change and amenity migration for members of diverse rural communities. We engage with recent amenity migration and political ecology literature that focuses on social constructions of nature and landscapes, and how these constructions affect the attitudes and opinions of community members. We use our case study of a mail-based survey in Down East, North Carolina to suggest that the ways in which people conceptualize the particular ‘natures’ and landscapes of a place matters in terms of shaping people’s attitudes with respect to ongoing processes of change. We find that people’s opinions about environment, culture, and land use are often superficially similar but that when conflicts arise or particular actions are considered, substantial differences in people’s underlying conceptual frameworks are revealed. In particular we find that despite widespread shared appreciation of the environment and culture Down East, differing interpretations of these key terms lead to potential misunderstandings and land use planning challenges.     

Reference Values Following ISO Guidelines for Frequently Requested Rock Reference Materials

We present new reference values for nineteen USGS, GSJ and GIT‐IWG rock reference materials that belong to the most accessed samples of the GeoReM database. The determination of the reference values and their uncertainties at the 95% confidence level follows as closely as possible ISO guidelines and the Certification Protocol of the International Association of Geoanalysts. We used analytical data obtained by the state‐of‐the‐art techniques published mainly in the last 20 years and available in GeoReM. The data are grouped into four categories of different levels of metrological confidence, starting with isotope dilution mass spectrometry as a primary method. Data quality was checked by careful investigation of analytical procedures and by the application of the Horwitz function. As a result, we assign a new and more reliable set of reference values and respective uncertainties for major, minor and a large group of trace elements of the nineteen investigated rock reference materials.     

Barium partitioning in coccoliths of Emiliania huxleyi

The coccolithophore Emiliania huxleyi was grown in seawater under different Ba concentrations. The relationship of coccolith Ba/Ca ratio and seawater Ba/Ca ratio was found to be linear. The linear regression yields the apparent Ba exchange coefficient of 0.10. Our data support a recently proposed generic model (Langer G., Gussone N., Nehrke G., Riebesell U., Eisenhauer A., Kuhnert H., Rost B., Trimborn S., and Thoms S. (2006) Coccolith strontium to calcium ratios in Emiliania huxleyi: the dependence on seawater strontium and calcium concentrations. Limnol. Oceanogr.51, 310-320.) developed for explaining apparent exchange coefficients of metabolically inert divalent trace metals, such as Sr, in E. huxleyi. This model represents the first approach combining cell physiological processes and data from inorganic precipitation experiments, which quantitatively explains coccolith apparent Sr and Ba exchange coefficients.     

Photometry of Galaxies in the Field of the Galaxy Cluster aBELL 1781

A method for determing the brightness and diameter of galaxies in a large field on Schmidt plates by automatic scanning with a microphotometer is described and applied to the ABELL cluster A 1781. The accuracy of this method is tested. The overall errors (r.m.s.) of brightness and diameter are 0.16 mag and 0″.44. The cluster A 1781 has been prooved to be a very poor cluster of about 10 members up to m_B ≈ 19^m.5.     

Catalogue of Shakhbazian compact groups of galaxies. V.

We present the position and references (if available) of all the galaxies of the Shakhbazian survey being the largest survey of compact galaxy groups. For the estimation of the coordinates the Digitized Sky Survey was used. This paper contains the data of 48 Shakhbazian groups north of δ > + 2deg;30' (Shkh 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 25, 26, 28, 29, 31, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56).