Since c. 3.1 Ga, pegmatite mineral deposits in orogenic areas have been formed throughout geological time in pulses, alternating with total absence of generating activity. The higher activity peaks of 2.65–2.60, 1.90–1.85, 1.00–0.95, and 0.30–0.25 Ga suggest a quasi-regular periodicity of 0.8±0.1 Ga. This series is dominated by pegmatites of Laurasian blocks. The lower peaks at 2.85–2.80, 2.10–2.05, 1.20–1.15, and the higher one at 0.55–0.50 make up another series represented by pegmatites in Gondwanan blocks only. Each pegmatite class is characterized by a life cycle of its own, from inception to peak through to decline and eventual extinction. The longest cycle is recorded for the rare-metal class deposits, which first appeared in the Mesoarchaean and persisted through all the later eras, deteriorating gradually after the Early Precambrian. Muscovite pegmatites first appeared in the Palaeoproterozoic and reached the end of their life cycle at the Palaeozoic–Mesozoic boundary. The miarolitic class of pegmatite deposits in orogenic setting first came into being in the terminal Mesoproterozoic and dominated the pegmatite metallogeny of many Phanerozoic belts. The evolution of the pegmatite classes was controlled by the general cooling of the Earth and by associated changes in the tectonics of the lithosphere.Supplementary material:Geochronological data used is available at http://www.geolsoc.org.uk/SUP18435.

The results of formal model design of a major intersection area essential for providing residents with transport accessibility and mobility are presented in the article. Simulation methods were applied to develop a model. The quantitative and qualitative characteristics crucial for the functioning of the model as its input parameters were determined. The importance of using a model when modelling different behavior scenarios of model objects based on typical situations of the real world is established.

The intensity of lithium accumulation through geological time has been analyzed. For this purpose we used the data on mineral deposits which have already exploited or potentially are of economic interest and which contain at least 0.1 × 10 6 tons of Li 2 O. Their formation was pronounced discrete and took place at various geological epochs from the Later Mesoarchean to Holocene. Each known supercontinent cycle differs in one way or another in the metallogeny of lithium. In the earliest cycles, Kenoran, Columbian, and Rodinian, exclusively pegmatite lithium deposits were generated. Moreover, this type is the only through one over the geological history, because such objects are also known in the Pangean and Amasian cycles. However, both the maximal number of such pegmatites and highest lithium grades are known for the oldest Kenoran cycle. This allows us to suppose that the Archean conditions were particularly favorable for lithium-bearing pegmatites. The lithium potential of the Pangean cycle also is mainly formed by pegmatites, except small part of resources related to lithium-fluorine (Li-F) rare-metal granites. The current Amasian cycle is far from the finish and the most diverse in types of lithium deposits. Pegmatites and Li-F granites in total contain only a tenth of the cycle's resources. Known in the Miocene-Quaternary only, the epithermal stratabound deposits and especially lithium-bearing brines in salars play a main role in the cycle. In spite of the lowest lithium contents, exactly the last type gives the maximal part in total resources, as well in lithium extraction, due to the relative simplicity and efficiency of used extraction technologies. KEYWORDS: Metallogeny; lithium deposits; geological history; supercontinent cycle. Citation: Tkachev, A. V., D. V. Rundqvist, and N. A. Vishnevskaya (2018), Metallogeny of lithium through geological time, Russ.

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