Late Pleistocene–Holocene environmental and cultural changes in Primorye, southern Russian Far East: A review

This article presents an analytical review of the available palaeoenvironmental and archaeological records from the southern part (ca. 42°18′–45°30′N) of Primorye spanning the last ca. 21,000 years. The outlined climate and environmental history of the coastal and continental zones of southern Primorye, based mainly on vegetation reconstructions derived from the study of fossil pollen from sedimentary deposits from various archives, is compared with the archaeological cultural sequence of the region. This shows synchronicity between several phases of climate change and cultural transition, migration and changes in population numbers and/or subsistence strategies. The pronounced warming trend during the Early Holocene (Preboreal and Boreal stages) is associated with increasing numbers of long-term camp sites of the Late Palaeolithic hunter-gatherers and a growing importance of aquatic food resources. The Holocene maximum temperature and moisture conditions during the Atlantic stage were paralleled by the emergence and flourishing of the Neolithic Rudnaya, Vetka and Boisman cultures (ca. 7.7–5.5 14C ka BP/8.5–6.2 cal ka BP). The latter was a specialised maritime forager culture distributed along the Sea of Japan coast, which likely reflects climate conditions and sea water temperatures that promoted a broad spectrum of marine food resources. Towards the end of the Atlantic stage, sea levels decreased and transformed the coastal landscape of southern Primorye, which probably contributed to the decline of the Boisman culture. At the same time, the climate started to become cooler, which is likely related to the eastward migration of Zaisanovskaya culture groups from more continental (cooler) regions to milder southern Primorye. Continuous cooling during the Subboreal was accompanied by further immigrations of Zaisanovskaya people and an increase in millet cultivation, which probably occurred in the region between ca. 4.6–4.1 14C ka BP/5.3–4.6 cal ka BP. With the emergence of the Palaeometal Epoch cultures (ca. 3.6 14C ka BP/4.0 cal ka BP), food production diversified (growing number of cultivated crops, animal husbandry) and intensified, which probably decreased the people's dependence on climatic conditions unfavourable for food procurement. However, the maximum flourishing (ca. 2.8–2.6 14C ka BP/2.9–2.6 cal ka BP) of the Palaeometal Epoch Yankovskaya culture, represented by a maximum number of documented settlement sites in Primorye's prehistoric sequence, was likely related to a coeval short phase of climate amelioration with higher air and sea water temperatures and an increased sea level, which promoted agriculture and a higher productivity of coastal waters

Evidence of millet and millet agriculture in the Far East Region of Russia derived from archaeobotanical data and radiocarbon dating

Agriculture based on broomcorn and foxtail millet has been identified as one of the main drivers of population expansion and/or resource and innovation transfer across Neolithic and Bronze Age Eurasia. However, accurate reconstruction of spatio-temporal patterns of millet spread within and outside China remains a challenging issue. Here we use a representative set of 27 millet-based radiocarbon (14C) dates from southern Primorye to reconstruct when millet cultivation became part of hunter-fisher-gatherer subsistence in this vast southeasternmost region of Russia. The spatio-temporal distribution of the 14C data demonstrates the following picture. After the earliest conventionally accepted (although not directly dated) appearance of millet at the Krounovka-1 site in the Suifen (Razdol'naya) River catchment west of Khanka Lake around 3521–3356 BCE (95.4% probability range of calibrated ages of wood charcoal), millet agriculture is registered at the site Gvozdevo-4 located on the southern coastal plains northeast of the mouth of the Tumen (Tumannaya) River in the first half of the 3rd millennium BCE. Several archaeological sites (Novoselishche-4, Bogolyubovka-1, Rettikhovka Geologicheskaya-1, Risovoe-4) with directly dated millet indicate the spread of millet cultivation across the fertile plains around Khanka Lake during the second half of the 3rd millennium BCE. The dates obtained from the Olga-10 site on the eastern coastal plains along the Sea of Japan suggest that millet contributed to the food economy there from the beginning of the 2nd millennium BCE. The presented dataset shows the presence of millet in the north-eastern part of the study region (i.e. at the Glazovka-gorodishche site) in the second half of the 1st millennium BCE. Our dataset demonstrates that millet has been cultivated in southern Primorye since the Late Neolithic, when small-scale agriculture was introduced by Zaisanovskaya culture groups archaeologically documented in the study region and neighbouring regions of China and North Korea. This indicates that millet was an integral part of the subsistence economy of the local populations throughout the entire period under review

Silica-supported Fe-Mo-O catalysts for selective oxidation of propylene glycol

Selective oxidation of propylene glycol is studied over silica-supported FeMoO catalysts with different Mo/Fe molar ratio. The catalysts are synthesized by wetness impregnation method and characterized by XRD, UV–vis, Raman spectroscopy, TPR and DFT methods. The catalytic properties are tested under gas phase conditions at 350 °C. The selectivity towards methylglyoxal formation is shown to be determined by the Mo/Fe molar ratio. The 55% selectivity towards methylglyoxal is achieved at Mo/Fe molar ratio of 3:1 through OH activation and CH bond scission route. CC bond cleavage route results in predominant formaldehyde formation at the Mo/Fe molar ratio of 1:2