The United Verde orebody, a Proterozoic volcanogenic massive sulfide deposit, is hosted by the Cleopatra Formation. The Cleopatra Formation is subdivided into two distinct members, the Upper and Lower, on the basis of alteration facies, whole rock geochemistry and the chemistry of alteration minerals. The Lower member was deposited prior to ore deposition and consists of five major alteration facies. Facies Bl, the most distant from the orebody represents the recharge area for the ore-forming fluid. Facies B2 surrounds the major discharge area or the chlorite pipe. These three facies contain chlorite and quartz as alteration minerals in variable amounts. Two facies, 81 and S2, contain quartz and sericite as alteration minerals. Mass balance calculations show progressive removal of Na and Ca, and addition of MgO and FeO* from the area of recharge (facies Bl) to facies B2 to the chlorite pipe. Whole rock δ¹⁸O values are high relative to least altered Cleopatra Formation in the recharge area and low in the discharge zone. Mineralogy and geochemistry of samples from the Upper member indicate that it was deposited following ore deposition and interacted with fluids rich in silica and iron. The hydrothermal fluid, which is interpreted to have been seawater, evolved to a high temperature slightly acidic, reduced fluid during water-rock interaction(log a₀₂ = -33 to -41; log a(H2S) = -2.6 to -5.0). The fluid δ¹⁸O and δ¹³C₀₂ values increased. Calculated δ¹³C₀₂ and δ¹⁸O fluid values, and sphalerite and chlorite chemistry imply that mixing of the hydrothermal fluid with seawater occurred in the orebody. the upper The levels of the chlorite pipe and in limited range in δ³⁴S values of sulfides is consistent with the derivation of the oreforming fluids from the reduced basal layer of a stratified basin. The study area represents only a small part of the United Verde circulation cell. Increased δ¹⁸O values of the fluid, and the need for a source of Mg, Fe and other metals suggest that the fluids may have circulated into the Shea Basalt.

A geochemical approach to the evaluation of the chemistry of natural recharge processes in the Tucson basin was used to identify the major minerals controlling the evolution of ground water chemistry and to assess the viability of recharging imported Central Arizona Project water supplies. Well cuttings analyses and water quality samples from over 65 wells in the basin were used as input to the geochemical computer model PATH4 (Helgeson, 1970) and the sequence of aqueous species and mineral production in a recharge reference volume examined. The study reveals that natural processes in the basin lead to the increase in dissolved solids content in ground water over time and the production of secondary minerals such as calcite, calcium montmorillonite, kaolinite and poorly crystallized alumino-silicate phases. Secondary minerals grow into aquifer pore spaces and may, over time, be responsible for the reduction in aquifer porosity and the specific capacity of wells. The recharge of imported Central Arizona Project water will lead to an increase in the dissolved solids content of ground water and may, in certain areas of the basin, lead to the enhanced production of secondary minerals. The use of CAP water as a recharge source must be guided by the geochemical factors which influence the nature and scope of reactions between CAP water and the Tucson aquifer matrix. The study demonstrates the need for and identifies water quality and aquifer matrix criteria for the assessment of sources of recharge water and recharge facility sites. The use of geochemistry as a tool for quantitatively assessing ground water quality is demonstrated.

The thesis is focused on the analysis of the railway transport within the selected region and it is divided to two parts -- theoretical and analytical. In its theoretical part the thesis deals with issues of the segment of transport within its economic dimension and with the impact of the railway transport on the regional economy. The analytical part is focused on the analysis of the impact of the railway transport on the selected Kroměříž region. The main aim of this thesis is to find out direct economic influence of the railway transport on the Kroměříž region. To reach this aim the method of selected data evaluation is used. The group of these data contains regional railway infrastructure characteristics, personal transport data, goods transport data, employment and investments.

In the tropics, widespread deforestation and conversion of primary forests to agricultural and pasture lands has resulted in losses of composition, structure, and functions of forest landscapes. Deforestation in the tropics is typically preformed via slash-and-burn practices; the byproducts from combustion have been identified as the second-highest form of anthropogenically derived 'greenhouse-gases' (such as carbon dioxide) to the atmosphere, and have been linked to the warming of the earth. Landscape-scale measures of species composition and biomass structure of primary forests are important for two reasons: (i) they provide accurate, land-based measures to predict what has been lost due to land-uses, and (ii) they aid in the discovery of key factors which explain patterns in compositional and structural diversity that are useful for defining conservation objectives. In this thesis, I enumerate the landscape-level patterns in species composition and biomass and C structure for 20-0.79 ha primary tropical forest stands within the region of "Los Tuxtlas", Veracruz, Mexico. These 20 sites were selected to capture the variability in composition and structure with respect to an array of environmental variables. These variables included a wide elevational range (15-1280 m.a.s.l.), variable slopes (Range: 3-41% slope), 3 soil-types (ash derived, lava flows, and weathered soils), a gradient of mean annual temperatures (~19.5-25.7��C), a broad precipitation range (2500 - 4000 mm year�����), a rainfall frequency range (i.e. max rainfall in 24 hours; ranged 30->100 mm day�����), and 3 Holdridge Life Zones (Tropical Moist Forest, Subtropical Wet Forest, and Subtropical Lower Montane Rain Forest). Species composition was highly correlated with the environmental variables, particularly elevation. In general for plants ���10 cm dbh, site species richness declined at a rate of ~2 species per 100 m rise in elevation. Forest sites located at similar elevations were most similar in their species compositions as compared with sites separated by large elevational differences. Despite the gradual change in species richness and composition, four sub-regions, or forest environments, within Los Tuxtlas were identified that had different species compositions and distinct combinations of elevation, soil-types, and climates. These four sub-regions were described as community-types according to their geographic location: Lowland-Reserve (LR), La Perla Plateau (LP), Volcanic Upslope (VU), and Cloud Forests (CF). The LR, LP, and VU community-types were coarsely described as Tropical Evergreen Forests (TEF's; INEGI 2001). All community-types corresponded with classifications within the Holdridge Life Zone System; the LR community-type was classified as Tropical (transition to Subtropical) Moist Forest; LP and VU community-types were classified as Subtropical Wet Forest, and the Cloud Forest community-type was classified as Subtropical Lower Montane Rain Forest. These community-types and Life Zones are useful tools for conservation, as they represent unique forests that collectively capture much of the variation in the species richness and compositional diversity of the Los Tuxtlas region. Unlike species composition, the variability in forest structure among the 18 TEF sites was not associated with the environmental variables of the Los Tuxtlas landscape. On average, TEF's had a total aboveground biomass (TAGB) of 422 �� 17 Mg ha����� and 205 �� 8 Mg ha����� total aboveground carbon (C). The TAGB and C pools for Cloud Forests was ~18% lower than TEF's, and averaged 346 �� 1 and 168 �� 1 Mg ha�����, respectively. The majority of this biomass difference was due to large trees within the forest structure. Cloud Forests had generally fewer trees ���70 cm dbh, and a more even distribution of trees 30-70 cm dbh than TEF's. The biomass contribution of large trees (���70 cm dbh) accounted for most, if not all, of the variation in TAGB and C for these tropical forests. The relatively high TAGB and C pools implicates Los Tuxtlas forests as a significant pool of aboveground biomass and C within the Neotropics. / Graduation date: 2002

Univ., Diss. u.d.T.: Povero, Chiara: Frontiere: ceti, territori culture nell'Italia moderna--Torino, 2003. / Contains bibliography, bibl. references, notes, indices and appendices (p. 347-388).

Not available / text

No description available.

No description available.

Research for a dissolved nitrogen budget was conducted at Mer Bleue bog near Ottawa, ON, from May 20, 2003 to May 21, 2004. Mer Bleue is located within an area experiencing the highest levels of atmospheric nitrogen deposition in North America, although these levels are only low to moderate compared to those in Europe. Continuous measurements of precipitation, evapotranspiration, bog water table level and outflow water depth were used in conjunction with discrete measurements of precipitation and outflow to determine the hydrologic budget. Water samples were taken from precipitation collectors, piezometers at various depths and locations throughout the bog, and an outflow point in order to gauge changes and patterns in chemical concentrations at various points throughout the bog. The nature of the bog morphology and landscape allowed for collection of water samples from a single outflow point. / Chemical analysis combined with the water budget revealed that the majority of the dissolved nitrogen is entering the bog as NO3-N and NH 4-N (inorganic nitrogen), and leaving the bog as dissolved organic nitrogen (DON). Export of nitrogen was generally low relative to the input, and was only a very small fraction of the huge amount of nitrogen stored in the bog. Bog porewater concentrations were dominated by DON and did not show spatial patterns in relation to the bog edge. When comparing the annual accretion of nitrogen at the bog to the long-term storage numbers, it was apparent that there is a missing source of nitrogen. From the literature and patterns in the bog, it appears that this missing input at Mer Bleue is likely due to a combination of previously unmeasured nitrogen fixation and more diverse usage of DON by bog vegetation.

A hydrological and biogeochemical study was undertaken at the Mer Bleue bog, Ottawa, Ontario, Canada from May 22, 1998 to May 21, 1999. Basin runoff was generated by groundwater discharge at the peatland margin, and groundwater discharge was controlled by hydraulic gradients and horizontal hydraulic conductivities (Kh). Flux of dissolved organic carbon (DOC) measured at the basin outflow was 8.3 g C m-2 yr-1 and compared to within 23% of DOC flux estimated using a Dupuit approximation of seepage during the ice-free season. Annual DOC flux was 11% of the annual carbon sink. / Flownet analysis showed that seasonal patterns of groundwater flow were controlled by boundary condition changes that resulted from precipitation and evapotranspiration events. A pattern of recharge was most common over the hydrological year, but a discharge pattern was observed during a 40 day groundwater flow reversal. Evaluation of the peatland recharge-discharge function using in situ sodium concentrations and a diffusion model revealed that the peatland is a long-term recharge system. It is hypothesized that peatland biogeochemical function is controlled by long-term recharge despite annual occurrence of groundwater flow reversals.