Existing views on the tectonic evolution of the Central Asian orogenic belt (CAOB) are highly controversial and the Neoproterozoic to Cambrian stages of this evolution remain the most enigmatic. However, the views on the Paleozoic evolution of the CAOB crucially depend on these early stages, as different choices of the starting point lead to very dissimilar Paleozoic reconstructions. In this context numerous microcontinents with the Precambrian basement that are included in the mosaic structure of Kazakhstan, Tien Shan, Altai and Mongolia are of particular interest. We undertook a paleomagnetic, geochemical and geochronological study of the Neoproterozoic volcanics from one of these units — the Baydaric microcontinent in Central Mongolia. According to U–Pb (laser ablation) dating the age of the studied Dzabkhan Volcanics is about 770–805 Ma. Thermal demagnetization revealed that most of the studied samples retained a pre-tilting component, whose primary origin is supported by a conglomerate test. These new data, together with available geological information allow us to conclude that about 770–800 Ma ago the Baydaric domain was located at a latitude of 47 (+16/-12)° N and belonged to one of the following plates: India, South China, Tarim or Australia.

Many scientists traditionally believe that the ore (and not only ore) matter of most endogenous economic minerals comes directly from the mantle or through the mantle matter differentiation and invasion of differentiated magmas in the crust together with water fluids rising from Earth’s depth. However, this assumption is right only in part as the entire matter of the continental crust, including ore elements, had been indeed released in the past from the mantle along with the other rock-forming oxides. In substance, however, this assumption is the “path of least resistance” as it allows us to hide our lack of knowledge of the real mechanisms of local crust enrichment with trace elements in a “black box” of the mantle and to substitute one complex problem with another one, no less complex. Indeed, the entire complexity of the classical approach to explaining the formation causes of local ore and other trace element accumulations in Earth’s crust is in that the concentration of most of them in the mantle is disappearingly low, whereas in commercial deposits it is relatively high and reaches sometimes top-cut grade value. For instance, gold and uranium concentration in the present-day mantle is on the order of 10-9; mercury and thorium 10-8; silver, tantalum, tungsten, platinum and lead 10-7; lithium, niobium, molybdenum and tin 10-6, etc., whereas in commercial deposits the concentration of these rare elements may rise to fractions and even whole percentages. <...>

Several gold deposits discovered since 1990 in the central Pequop Mountains of Elko County, northeastern Nevada, make up the new Pequop mining district. The most advanced projects, including Long Canyon and West Pequop, have a combined resource exceeding 42.5 tonnes Au and growing. Favorable open-pit mining economics are generated by high-grade, oxidized gold deposits above the water table.

The deposits exhibit characteristics typical of Carlin-type gold deposits, including limestone and calcareous siliciclastic host rocks, collapse breccias, and <5 micron gold grains in rims of oxidized arsenian pyrite grains. Host rocks are decalcified, argillized, and locally silicified (jasperoid). Some gold mineralization, particularly at Long Canyon, occurs along the margins of competent blocks of Cambrian Notch Peak dolomite in contact with limestone.