1. Исследования Калловиана долины Роны

2. Стратиграфические и палеонтологические данные средней юры в Ла-Вульт-сюр-Рон

Mining and metals continue to be among the best performing global equity sectors, but conflicting issues – from “pricing bubbles”, “imminent recessions”, “demand destruction” to “resource scarcity”- are confusing investors. Nevertheless, the importance of mining to the world has become very apparent in recent years, as commodity and equity prices have exceeded most expectations.
Therefore, investments in commodities become more attractive as a long-term investment as they are a safe haven in times of  economic crisis and provide a protection against currency devaluation. Thus, it is useful to know how to value metals and mining companies <...>

On the basis of textural features and spatial distributions, both supergene and hypogene origins have been proposed for alunite in sediment-hosted micron gold deposits. If alunite is indeed primary, its presence provides important constraints on the chemistry of the ore fluid. Thus, determination of the genesis of alunite is critical to the understanding of the geologic history of these ore deposits.

At the Post deposit in Nevada K/Ar ages of alunite are much younger than the age of mineralization. Sulfur isotope compositions of alunite from several sediment-hosted micron gold deposits are virtually identical to those of sulfides, suggesting that alunite sulfur came from quantitative (closed-system) oxidation of primary sulfide minerals during weathering. Sulfur and oxygen isotope compositions of barite are markedly different from those of alunite. The oxygen and hydrogen isotope compositions of alunite fall in the supergene alunite fields; data for cogenetic kaolinite fall on the kaolinite line, whereas those for hypogene kaolinite do not. From all available petrographic and geochemical data, it would appear that alunite in the micron gold deposits of Nevada is entirely of secondary supergene origin.

Africa holds extraordinary prospects for the paleontological investigation of mammalian evolution. Largely still inhabited by relic Plio-Pleistocene mammalian faunas, it is populated by animals such as giraffes, rhinos, lions, gazelles, zebras, okapis, and giant forest hogs, as well as descendants of endemics of longer residence such as hyraxes and catarrhine primates, beneficiaries of having been sheltered from the most extreme effects of climate and ecological change due to the position of the landmass astride the equator, the only continent to span both northern and southern temperate zones (Sanders and Werdelin, 2010). Occupying 20% of the world’s landmass, Africa is home to approximately a quarter of all living mammals (Kingdon, 1997; Medellín and Soberón, 1999), encompassing a tremendous range of species and adaptations, fostered by the size and physical and ecological heterogeneity of the continent (Kingdon, 1989; O’Brien and Peters, 1999). <...>