Origin of Geochemical Variability by Arc-Continent Collision in the Biru Area, Southern Sulawesi (Indonesia)

Analyses of igneous rocks from the Eocene calc-alkaline andMiocene potassic volcanic arc in southwest Sulawesi indicatethat magmas became more heterogeneous in their trace elementand Pb–Sr–Nd isotopic signature following the collisionof the Buton microcontinent with the arc at     

Geoecological Characteristics of Lake Seliger

Data of hydrological and hydrochemical observations conducted in August 2000 at Lake Seliger and its major tributaries are presented. The analyzed characteristics included: O₂, H₂S, CH₄, microelements; mineral and organic compounds of P and N, ionic composition components (HCO₃ ^–, Cl^–, Na⁺, K⁺, dry residue, pH; color index, electrical conductivity. Bottom sediment samples were analyzed for microelement concentrations, CH₄, oil hydrocarbons. The influence of the basin on the ecological state of the lake was assessed, and tendencies in the evolution of its ecosystem are analyzed. It is shown that the ecological conditions of the lake has not changed significantly since 1960–1991, however, nutrient concentrations in the lake water was found to increase.     

Soil degradation: a global problem endangering sustainable development

1 Introduction Soil is not only the major natural resource on which human being depends for the production of food, feed, fiber, renewable energy and raw materials, but also plays a key role in maintaining the complex terrestrial ecosystems and climate systems of this planet. Recent rapid increase in the human population is placing a great strain on the worlds soil resources. Only about 11% of the global land surface covered by the soils are being used to raise crops and livestock, in other …     

A general model for estimating actual evaporation from non-saturated surfaces

Based on energy balance equation and mass transfer equation, a general model to estimate actual evaporation from non-saturated surfaces was derived. Making use of two concepts, “relative evaporation” and “relative drying power”, a relationship was established to account for the departure from saturated conditions. Using this model, the actual evaporation (evapotranspiration) can be calculated without the need of potential evaporation estimation. Furthermore, the model requires only a few meteorological parameters that are readily and routinely obtainable at standard weather stations. Based on nearly 30 years data of 432 meteorological stations and 512 hydrological stations in China, in combined with GIS, nine typical river basins were selected. Using the data of the selected river basins, the model was tested. The results show that the actual evaporation rate can be estimated with an error of less than 10% in most areas of China, except few years in the Yellow River Basin.     

Some Aspects of Resource Uncertainty and Their Economic Consequences in Assessment of the 1002 Area of the Arctic National Wildlife Refuge

Natural Resources Research - Exploration ventures in frontier areas have high risks. Before committing to them, firms prepare regional resource assessments to evaluate the potential payoffs. With...