Scientific results:
The Laboratory of paleoecological reconstructions was established in 2021. The main goal of the project is to collect and analyze proxy paleoenvironmetal achieves and to obtain comprehensive reconstructions based on modern analytical methods and climate models.
As part of the project, the first specialized ice core laboratory in Russia has been created. New ice cores were obtained as follows: the Katyn Plateau in the Bezengi Glacier accumulation area in 2021 4750 m asl, with a 93 m ice core drilled to bedrock; Ice core at the Ushkovsky volcano (Kamchatka) was drilled in 2022; 90.8 m ice core from the IGAN glacier in the Polar Urals was drilled in 2023.
A comprehensive paleoclimatic reconstruction for the Caucasus was completed based on isotopic compositions of Elbrus ice cores (West Plateau 2009, Eastern Summit 2020), dendrochronological data for the region including a reconstruction of summer air temperatures since 1596, and data on lake sediment from Lake Karakel. Additionally, published data on lake sediments and speleothems from the Middle East region were utilized. This resulted in an independent temperature reconstruction for the region spanning the past 1000 years.
The temperature variations in the Caucasus over the past millennium were primarily influenced by solar activity variability, as indicated by similarities between the isotopic composition of the Eastern Summit of Elbrus and Greenland ice cores, as well as solar activity records. Heavier isotopic composition in the records from 1100 to 1400 AD reflects the Medieval Climate Anomaly. This period, however, was not uniform, with two cooling periods around 1150-1200 AD and 1300 AD. New data on moraines ages from the Kashkataash and Donguz-Orun glaciers indicate glacier advances in 1200 and 1300 AD, respectively. Another cold phase occurred in the 15th century lasting nearly a century, coinciding with the Sporer Minimum and marking the beginning of the Little Ice Age. Limited moraine dates suggest that many moraines formed during this period were later buried by subsequent glacier advances. Based on Eastern Summit Elbrus ice core isotopic record, LIA cooling phase began in the late 17th century, consisting of two cooling periods lasting 25-30 years with a hiatus in the 1730s. The most significant glacier advance was observed in the mid-19th century confirmed also by minimum isotopic concentration values over 800 years.
Recent warming, reflected in the ice core isotopic record and temperature reconstruction, reached the level of the late 14th century by the 1980s, marking the warmest period in at least 1000 years, accompanied by increased precipitation in both winter and summer seasons.
Measurements of methane in samples from the Eastern Summit Elbrus ice core were done using continuous flow analysis system. Synchronization of methane record with global records from Greenland and Antarctic ice cores, confirmed the approximate age of the Elbrus ice core (at least 900 years in the upper 75 m). Methane concentrations remained within 670-690 ppbpv until the late 18th century, after which concentrations increased to 1800 ppbpv in the 2000s. Data from 1000 to 1800 AD are of a particular interest where several known periods of increased methane concentration detected in Greenland and Antarctic ice cores during 1300-1400 AD and 1500-1600 AD. These periods are also observed in Elbrus core. Additional short period of increased methane concentrations (700-720 ppbpv) was found during 1650-1680 AD.
Carbonaceous micro-particles associated with the development of the Vorkuta coalfield were found in the IGAN glacier ice core from the Polar Urals,
Isotopic analysis of tree ring samples from the European part of Russia was conducted. Results included measurements of stable carbon isotope δC13.
Comparison between climate model data and dendroclimatic reconstructions of summer temperatures based on annual tree ring optical density for the Solovetsky Islands and the Northern Caucasus (1500-1850 AD) demonstrated significant responses of global annual average temperature to volcanic eruptions in the following years: 1600 (~0.7-0.9°C), 1640 (~0.6°C), 1695 (~0.5°C), 1783 (~0-1°C), 1809 (~0.4-0.9°C), and 1815 (~0.5-1.7°C).
The eruption history of Elbrus was reconstructed using tephra analysis in Caucasus sediments revealing a previously unknown stage of major explosive eruptions occurring between ~520 and 85 thousand years ago. At least five eruptions were identified, with tephra spread distances of 150-560 km from the source.
Studies of paleofire dynamics in the western Caucasus based on paleoanthracological analysis of Lake Huko sedimements provided insight into forest fire history over the last 10,500 years. Overall, low fire activity was recorded in the western Caucasus during the Holocene except for a period between 4.0 and 5.2 thousand years ago. An increased fire frequency and charcoal particle accumulation observed in the last 500 years. A series of fire episodes corresponded to major catastrophic fires in adjacent areas, coinciding with the event 4.2 thousand years ago, characterized by climatic instability in the Northern Hemisphere.
The first chronology of annual tree ring cell parameters for the European part of Russia was established, measuring parameters such as cell wall thickness, lumen area, average cell area, and minimum, average, and maximum cell counts for each tree ring.
Fire activity from the early Holocene 10600-10200 cal. BP was documented for the Tersky Keive of the Kola Peninsula, indicating sufficient biomass for intensive burning and production of significant amounts of charcoal, including from tree species.
Pollen analysis of the Kich outcrop in Kamchatka allowed identification of six stages in the development of vegetation and climate over the last 3,000 years, showing gradual warming trends and the spread of coniferous forests starting around 720 AD.
A reconstruction of paleofires for the forest zone of the Central European plain was created, integrating data from macroscopic charcoal particles in peat deposits from two model territories: the Ustyan Plateau in the southern Arkhangelsk region (mid taiga) and the northeastern Ryazan region (landscape area preceding the Meshchera lowland, mixed coniferous-broadleaf forests). An integral model of forest fire history over the last 9000 years was developed using the "Paleofire" software package. Data were compared with major climatic changes during the Holocene and signs of anthropogenic vegetation changes.
A metadata inventory of all existing natural paleoarchives in the repository of the Institute of Geography of the Russian Academy of Sciences was completed. Archives (lake sediment cores, ice cores, loess samples, tree ring samples, tephra samples, archaeological samples) contain information on changes in conditions and ages of various geosystems at the end of the Quaternary period.
Organizational and infrastructural changes:
Sspecialized ice core laboratory has been established within the glaciology department.
Education and personnel occupational retraining:
Several new classes have been developed and implemented at the Faculty of Geography and Geoinformation Technologies at HSE University with hte direct involvement of laboratory staff. The "Earth Spheres" class within the cryosphere section includes a series of theoretical and practical sessions in the laboratory. The "Changes in the Natural Environment in the Past and Methods of Paleogeography" class is conducted using laboratory's facilities with the participation of the majority of scientific groups.
A variety of methodological approaches, as well as examples and data for seminars in the "Mathematical Methods, Analysis, and Data Visualization in the Study of Natural Systems," class were obtained within the framework of the project.
Members of laboratory staff have successfully defended 4 dissertations for the degree of Candidate of Sciences and 1 dissertation for the degree of Doctor of Sciences.
Cooperation:
Arctic and Antarctic Research Institute (AARI), Russia; Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences; A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences; Lomonosov Moscow State University (MSU), Russia; Institute of Volcanology and Seismology, Far Eastern Branch of the Russian Academy of Sciences; British Antarctic Survey (BAS), United Kingdom; Laboratory of Environmental Geophysics, University Grenoble Alpes, France; Paul Scherrer Institute, Switzerland.
