New Data on Iron-Smelting Sites in the Kuektanar and Turgun Valleys, Southeastern Altai

This paper presents the findings relating to iron-smelting furnaces in the Kuektanar and Turgun valleys of the Russian Altai, which were part of the Chuya-Kurai metallurgical province and are undergoing rapid erosion. On the Chuya River, downstream of the mouth of the Kuektanar, we discovered hitherto unknown (and completely eroded) remains of furnaces. Radiocarbon dating of charcoal fragments from smelting furnaces (bloomeries) at Kuektanar-1 and 2 and Turgun-1, using both scintillation and AMS techniques, suggests the use of trees that grew in 5th–10th centuries AD as a fuel for metallurgical production. Dates of charcoal relating to the same iron-smelting event differ by over 300 years, probably because various parts of adult larches (Larix sibirica Ledeb.) were used, creating an “old wood” effect. Samples of uncharred bark in bloomery 2 at Kuektanar-1 suggest that the last smelting occurred in 655–765 AD. The totality of radiocarbon dates makes it possible to conclude that the furnaces were active during the Old Turkic period. The proximity of iron ore sources and the abundance of forest vegetation account for the wide use of iron-smelting by the nomads in the region. The erosion of the river bank where the furnaces are located allowed us to assess the erosion rate since their construction to be approximately 0.5 cm per year. © 2018 A.R. Agatova, R.K. Nepop, I.Y. Slyusarenko, V.S. Panov.The study was performed under Public Contract (Project No. 0330-2016-0015); archaeological studies were supported by the Russian Science Foundation (Project No. 14-50-00036), geological and geomorphological studies, including radiocarbon dating, were supported by the Russian Foundation for Basic Research (Project No. 16-05-01035)

Specific Effects of the 1988 Earthquake on Topography and Glaciation of the Tsambagarav Ridge (Mongolian Altai) Based on Remote Sensing and Field Data

Strong earthquakes could serve as a trigger for glacier detachment and associated ice–rock avalanches. The 1988 Tsambagarav earthquake (M = 6.4) initiated collapse of part of the glacier tongue and a further ice–rock avalanche with an abnormal 5 km long path in Zuslan valley, Tsambagarav ridge (Mongolian Altai). Early documentation of surface effects in 1988, remote sensing and field data gathered 16 and 30 years after this event allowed for the assessment of the seismic impact on a reduction of “damaged” glacier under conditions of global warming as well as estimating topography changes in this arid and seismically active area. Because of the earthquake, the glacier immediately lost 10.4 % of its area (0.1 km2 of tongue surface). Additionally, 56% of its area was lost during 1988–2015, shrinking much faster than neighboring glaciers of similar size and exposition. Collapse of snow–ice cornice in the accumulation zone could play a key role in rapid acceleration of the detached ice block and abnormally long path of the ice–rock avalanche. A large amount of debris material provided more than 16 years of ice melting. Downstream, the valley avalanche debris cover repeats the topography of underlying Pleistocene moraines, which should be considered in regional paleogeographical reconstructions. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The study was supported by State Assignment of IGM SB RAS and partly funded by Russian Science Foundation (grant 22-27-00447)

Archaeological sites as markers of Neopleistocene-Holocene hydrological system transformation in the Kurai and Chuya basins, Southeastern Altai: Results of geomorphological and geoarchaeological studies

Multidisciplinary studies using geomorphological, geoarchaeological, and geochronological approaches indicate contrasting environmental changes in Southeastern Altai, beginning in the Late Pleistocene. 29 new radiocarbon dates from the subaerial complex overlying Late Neopleistocene sediments in the high-altitude Kurai and Chuya basins confirm the degradation of a single ice-dammed reservoir in that area before the Early Holocene. In the first half of the Holocene, those basins were filled with isolated lakes. At the mouth of the Baratal River in the western Kurai basin, a reservoir with a water-level of at least 1480 m a.s.l. emerged ca 10–6.5 ka cal BP; whereas in the Chuya depression, numerous residual lakes existed at least 8 ka cal BP. Landslide- and moraine-dammed lakes between the depressions in the Chuya River valley existed until 7–3 ka cal BP, when they drained away. The state of preservation of in situ archaeological sites, their cultural affiliation, and their locations within the depressions and along the main Chuya valley attest to spatial and temporal changes in the hydrological system. This evolution in the second half of the Holocene did not entail major consequences for humans. All cataclysmic flood events took place (occurred) before 10–8 ka cal BP. © 2016 A.R. Agatova, R.K. Nepop, I.Y. Slyusarenko, V.S. Myglan, V.V. Barinov.Geomorphological studies, including radiocarbon dating, were supported by the Russian Foundation for Basic Research (Projects No. 15-05-06028 and 16-05-01035); archaeological and dendrochronological studies were supported by the Russian Science Foundation (Projects No. 14-50-00036 and 15-14-30011 respectively)

Влияние землетрясения 1988 г. на оледенение и рельеф массива Цамбагарав (Западная Монголия)

Early documentation of the consequences of the Tsambagarav earthquake happened on July 23, 1988 (M = 6.4) compiled by Soviet and Mongolian specialists allowed the authors, using the example of Tsambagarav (Mongolian Altai), to assess the impact of the seismic process on the reduction of mountain glaciation and topography of the trough valleys in the arid region of Central Asia. In 1988, in upper part of the Zuslan river valley, 13 days after the earthquake, the release of a fragment of one of the glaciers gave rise to an ice-rock avalanche «on an air cushion». Its deposits with a thickness of up to 30 m blocked the valley over a distance of 5 km. Analysis of space images taken in different time together with field researches revealed that as a result of the earthquake the glacier № 15 simultaneously lost 0.1 km2 of its tongue (10.4% of total area), as the whole in 1988–2015 it lost 56% of its area, whereas neighboring glaciers № 16 and 17, similar in size and the same exposure, lost significantly less – 35 and 15% of the area, respectively. Rapid shrinking of not only the glacier tongue, but also of its accumulation zone; the established deficit of ice volume in the broken off ice fragment (in comparison with initial assessment), and the abnormally long path of the avalanche made it possible to clarify the factors and mechanism of its initiation: the fall of the ice-snow ledge from the accumulation zone could lead to the rapid release of the broken ice fragment in the tongue part of the glacier. In 2004, 16 years after the avalanche, the buried ice in its deposits was still partially preserved, having completely degraded by 2019. The long time of the ice degradation process was caused by the high content (about half of the volume) of debris that armored the surface of avalanche sediments. The debris material of the avalanche repeats the relief of the underlying Pleistocene moraines, which may complicate the reconstruction of the number, scale and age of glacial events in avalanchehazardous areas. The relatively high rate of leveling of the avalanche traces and, as a consequence, the difficulties of their subsequent identification in the relief allow us to assume a greater number of avalanche releases, including seismic ones, in the recent geological past than it can be established at present in the Altai ridges.Ледник № 15 (по [3]), потерявший в результате Цамбагаравского землетрясения 1988 г. магнитудой М = 6,4 фрагмент языка (10,4% всей площади) и часть объёма в области аккумуляции, в период 1988–2015 гг. сократился на 56%, что больше сокращения соседних ледников (15–35%). Погребённый лёд в отложениях ледово-каменной лавины, заполнивших долину р. Зуслан на протяжении 5 км, частично сохранялся и в 2004 г.; полностью он растаял к 2019 г. Обломочный материал лавины повторяет рельеф подстилающих плейстоценовых морен, что может осложнить реконструкцию ледниковых событий в регионе. Уточнены факторы, определившие возникновение лавины на «воздушной подушке»

Археологические памятники как маркер перестройки неоплейстоцен-голоценовой гидросети Курайской и Чуйской впадин (Юго-Восточный Алтай): результаты геолого-геоморфологических и геоархеологических исследований

Multidisciplinary studies using geomorphological, geoarchaeological, and geochronological approaches indicate contrasting environmental changes in southeastern Altai beginning from the Late Pleistocene. Twenty-eight new radiocarbon dates from the subaerial complex overlying Late Neopleistocene sediments in the high-altitude Kurai and Chuya basins confi rm the degradation of a single ice-dammed reservoir in that area during the Early Holocene. In the first half of the Holocene, those basins were filled with isolated lakes. At the Baratal River mouth in the western Kurai basin, a reservoir with a water level of at least 1480 m a.s.l. emerged ca 10-6.5 ka BP, whereas in the Chuya depression, numerous residual lakes had existed at least 8 ka BP. Landslide- and morainedammed lakes between the depressions in the Chuya valley had existed until 7-3 ka BP, when they drained away. The preservation state of in situ archaeological sites, their cultural affiliation, and their location within the depressions and along the main Chuya valley attest to spatial and temporal changes of the hydrological system. This evolution occurred in the second half of the Holocene and did not entail major consequences for humans. © 2016 Siberian Branch of the Russian Academy of Sciences.Geomorphological studies, including radiocarbon dating, were supported by the Russian Foundation for Basic Research (Projects No. 15-05-06028 and 16-05-01035); archaeological and dendrochronological studies were supported by the Russian Science Foundation (Projects No. 14-50-00036 and 15-14-30011 respectively)

Archaeological Sites as Markers of Hydrosystem Transformation in the Kurai and Chuya Basins, Southeastern Altai, in the Late Pleistocene and Holocene. Summary of Findings and Paleogeographic Reconstructions

This paper is the second in a series of publications on various aspects of the relationships between man and environment in the highlands of southeastern Altai. In these studies, we assess the impact of climatic changes (evidenced by processes of glaciation and deglaciation, the emergence of ice-dammed and residual lakes, soil and peat formation, and seismic activity) on the succession of sedentary and nomadic cultures, and on the ranges of their distribution, in the Late Pleistocene and Holocene. Geochronological data on the evolution of Late Pleistocene ice-dammed lakes and Holocene residual lacustrine systems within the Kurai and Chuya intermountain basins, including our new findings based on geomorphological, geoarchaeological, and geochronological approaches, were summarized in the first paper of the series. Using Paleolithic sites for assessing the time in the Late Pleistocene when the Chuya paleolake emptied is unwarranted, because their estimated age limits are wide, many are likely redeposited, and most finds are random. However, analysis of the spatial distribution of in situ sites spanning the period from the Late Bronze Age to the Middle Ages has provided evidence regarding the transformation of Holocene hydrosystems. New radiocarbon dates indicate a substantial decrease of the Sartan glaciation before 14 ka cal BP, and desiccation of the last ice-dammed lakes within the Kurai and Chuya basins before 10 ka cal BP. The absence of Early Holocene archaeological sites in those areas may be due to the wide distribution of residual lakes in the bottoms of those depressions at that time. © 2017 A.R. Agatova, R.K. Nepop, I.Y. Slyusarenko.Geomorphological studies, including radiocarbon dating, were performed under Public Contract (Project No. 0330-2016-0015) and supported by the Russian Foundation for Basic Research (Projects No. 15-05-06028 and 16-05-01035); archaeological studies were supported by the Russian Science Foundation (Project No. 14-50-00036)

Climatically Driven Holocene Glacier Advances in the Russian Altai Based on Radiocarbon and OSL Dating and Tree Ring Analysis

Analysis of new chronological data, including 55 radiocarbon, 1 OSL, and 8 dendrochronological dates, obtained in the upper reaches of trough valleys within the Katun, North Chuya, South Chuya, and Chikhachev ranges, together with the 55 previously published ones, specifies climatically driven glacier dynamic in the Russian Altai. Available data refute the traditional concept of the Russian Altai Holocene glaciations as a consecutive retreat of the Late Pleistocene glaciation. Considerable and prolonged warming in the Early Holocene started no later than 11.3–11.4 cal kBP. It caused significant shrinking or even complete degradation of alpine glaciers and regeneration of forest vegetation 300–400 m above the modern upper timber limit. Stadial advances occurred in the middle of the Holocene (4.9–4.2 cal kBP), during the Historical (2.3–1.7 cal kBP), and the Aktru (LIA thirteenth–nineteenth century) stages. New radiocarbon ages of fossil soils limited glaciers expansion in the Middle Holocene by the size of the Historical moraine. Lesser glacial activity between 5 and 4 cal kBP is also supported by rapid reforestation in the heads of trough valleys. Glaciers advance within the Russian Altai, accompanied by accumulation of the Akkem moraine, could have occurred at the end of the Late Pleistocene. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The study was supported by the State Assignment of IGM SB RAS