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Project titleLast millennium environmental reconstruction in Kamchatka from the new ice core and other proxies
Project LeadMikhalenko Vladimir
AffiliationInstitute of Geography of the Russian Academy of Sciences,
|Implementation period||2022 - 2024|
Research area 07 - EARTH SCIENCES, 07-703 - Glaciology
Keywordsclimate change, ice cores, dendrochronology, tephra, sea ice, forest fires, biological productivity, lacustrine sediments, Kamchatka
Glaciers in Kamchatka, are more prone to destructive melting in response to global warming than in other high mountain areas. The most suitable location for deep ice core drilling in Kamchatka is the ice cap of the Gorshkov crater in the Ushkovsky volcano massif, where summer melt and melt water infiltration are significantly limited, and the flat glacier surface makes it fairly easy to estimate the age in the deep layers of the glacier using the ice flow model (Salamatin et al., 2000; Sato et al., 2014). This site has been shown to contain valuable climate information (Solomina et al., 1995, 2007). Ice cores from Kamchatka glaciers remain much less studied from the point of view of studying the environment in comparison with high-mountain cores obtained in the Alps, the Caucasus and Altai. In fact, only a few chemical studies were conducted in Kamchatka. One of them focused on biomass combustion using molecular organic indicators (levoglucosan and dehydroabietic, vanilic, and p-hydroxybenzoic acids) (Kawamura et al., 2012). Kamchatka is of great scientific interest in terms of studying boreal forest fires in Siberia and their recurrence due to changes in weather conditions (increased summer convective activity and the formation of lightning, a decrease in winter snow cover) Kawamura et al. (2012). There is a great need for a critical revision of the previously obtained results based on the Kamchatke ice cores, which contains very important information about forest fires in Siberia. Siberia, like Canada, are key regions of the boreal forest ecosystem, which is the dominant carbon pool. Another specific aspect, the parameters of which are potentially contained in the Kamchatka glaciers, is associated with the conditions of formation and distribution of sea ice in the Sea of Okhotsk. For this purpose, a preliminary study was carried out using melt layers and excess of deuterium (but not chemical composition) in a core from the Ichinsky glacier (Mount Ichinskaya, 3607 m) (Matoba et al., 2011). Obviously, further studies of the ice chemistry of Kamchatka glaciers are needed, in particular using sodium ion or methanesulfonate, which are usually analyzed using ion chromatography to study the past conditions of sea ice formation and distribution in this key region, one of the southernmost regions in the Northern Hemisphere. where seasonal sea ice forms every year. Other proxy data on Kamchatka Kamchatka, a region with numerous active volcanoes and glaciers, is of primary interest for our purposes. The region is very well studied in terms of tephrochronology (Ponomareva et al .., 2007, 2015), but this method still has great potential for dating other than volcanic (eg glacial) deposits. In climate reconstructions based on tree-ring chronologies, larch, spruce, and birch were used (Solomina et al., 2007, Wiles et al., 2015, Deck et al., 2017), but for this region, longer chronologies based on using a fin. Opportunities for improving the climatic signal in tree rings exist based on the optical density measurement method used in our group (Dolgova, 2016). Recently, significant efforts have been made to carry out paleoclimatic reconstructions and reconstructions of air pollution in the study of lacustrine sediments in Kamchatka (see Special issue Global and planetary change, 134). The authors of this collection argue: “Our conclusions and interpretations suffer to some extent from a lack of quantitative climate reconstructions. The next steps should be focused on increasing the geographic coverage of multidisciplinary paleolimnological sites in Kamchatka, improving the reliability of transfer functions and developing new quantitative reconstructions in addition to our qualitative ones. " (Brooks et al., 2015). We intend to perform the following works in Kamchatka: • Obtain a new ice core (200 m) in the coldest place - the crater of Ushkovsky volcano (average annual temperature -16 ° C). A light electromechanical drilling rig available at the Institute of Geology, Russian Academy of Sciences, will be used for drilling; • Ice cores from Ushkovskyi will be analyzed for the content of stable isotopes of oxygen and hydrogen, methane in air bubbles trapped in ice, ionic compounds including methanesulfonate, insoluble particles, organic carbon and tephra fragments; • We use these measurements to identify forest fire traces in the ice core. As shown (Legrand et al., 2016), the set of indicators for identifying fires is different for each region. In previous studies, only a few molecular organics have been studied. Only after conducting key studies on the selection of the optimal set of indicators will we decide whether additional information is needed from the measurement of organic molecular indicators, the analysis of which remains expensive; • Updating the chronology of larch and applying the optical density method to improve temperature reconstructions; • Collecting and analyzing fin wood to extend existing chronologies; • Study of the possibility of reconstructing the distribution of sea ice based on different sources; • Study of the possibility of using ice core for reconstruction of boreal forest fires. • Dating moraines and volcanic deposits using cosmogenic isotopes and tephrochronology methods; • Search for banded clays and study the possibility of using them to create high-resolution reconstructions on this basis. See List of references in # 4.14
For the first time, high-resolution reconstructions of climate and environmental changes will be combined based on all available data: ice core, tephra deposition, dendrochronological studies, and lake sediments. Ice cores: - For the first time the content of key inorganic compounds emitted into the atmosphere during volcanic eruptions (Cl, Br and I) will be reconstructed over the several past centuries. Such information on past emissions of halogens from volcanoes in Kamchatka will certainly be interesting for assessing the role of volcanoes in the tropospheric halogen budget. - Detailed reconstruction of high-resolution sea ice content in the Sea of Okhotsk basin using sodium, methanesulfonate and possibly halogens. - Obtaining new continuous records of the spread of fire and the productivity of vegetation cover in Kamchatka and in eastern Siberia, based on the content of organic carbon in the ice core. Tephra: For the first time, the history of explosive eruptions in a highly active volcanic region over the past hundreds of years will be reconstructed with high resolution. The eruptions of various volcanoes will be identified, trends in the composition of their tephras will be revealed, and the patterns of the distribution of eruptions in time will be considered. Confirmed or refuted the available obscure information about the recent activity of a number of volcanoes. The results obtained will be used to predict explosive activity and assess volcanic hazard. Dating of glacial deposits will be carried out, which will allow the reconstruction of glacier dynamics in the Holocene. Dendrochronology: For the first time, the change in biomass and dynamics of forest fires in Kamchatka will be reconstructed with high resolution. This will allow you to establish the growth of wood and its reserves. For the first time, chronologies of fires in two locations will be obtained: the Sredinny ridge and around the Klyuchevskaya group of volcanoes. A comparison of these chronologies will be made to identify synchronous events and major pyrogenic periods. For the first time, estimates of the dynamics of aboveground / total woody biomass / bioproductivity for the last 100-200 years in Kamchatka will be obtained. These estimates will be compared with similar estimates made from ice and lake sediment cores. For the first time for Kamchatka, the chronology of the optical density of annual rings of larch will be obtained and an analysis of its climatic response will be carried out. If a strong temperature signal is confirmed, an attempt will be made to reconstruct this parameter in the past. Lacustrine deposits: For the first time for Kamchatka, an attempt will be made to analyze lacustrine sediments to study the dynamics of glaciers in the Holocene, together with dendrochronological data, tephra analysis of moraine dating using tephra and cosmogenic isotopes.
Annotation of the results obtained in 2022
In September 2022, ice core drilling was carried out in the Gorshkov crater on the Ushkovsky volcano at an altitude of 3,950 m. The recovered core, 14 m long, was shipped to Moscow in a frozen condition. The cold laboratory of the Institute of Geography of the Russian Academy of Sciences performed stratigraphic description of the core and measured its density. Currently, chemical analyses of the ice core are being carried out. The snow and firn strata in the apex area of the Ushkovsky volcano crater are characterized by very high ice content as a result of freezing of melt water and liquid precipitation at subzero temperatures in the upper part of the glacier. The meteorological conditions during the period of work were characterized by active cyclonic activity related to the aggravation of the Far East branch of the polar front extending along the Aleutian Islands through the Kurils and Primorsky Krai. The aggravation of this section of the high-latitudinal planetary front zone was connected with the formation of a center of anomalously cold arctic air over the mainland Far East in combination with the outflow of marine tropical air over the Pacific Ocean area. As a result, the weather conditions were characterized by extreme instability. The mean temperature over a 10-day period (13-23 September) was -11°C. Maximum mean wind speeds averaged 27 m/s on 20 September. Wind gusts reached 40 m/s. During the period of work to the south-east of the Kamchatka Peninsula and at the drilling site, a frontal jet current was formed, characterized by the highest wind speed in the Northern Hemisphere. The concentrations of major inorganic (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, Br-, NO2-, NO3-, SO42-) and several organic (acetate and formate) ions were measured in the obtained core using ion chromatography. The main difference of the Ushkovsky volcano core from other previously studied ones is the very low contribution of anthropogenic sources of pollution. The concentrations of such typical fuel combustion markers as sulfate (SO42-) and nitrate (NO3-) are significantly lower (on average 118 ppb for the Kamchatka core vs. 394 ppb for the Caucasian core) compared to the values for the Elbrus core. This allows us to neglect the anthropogenic influence on the chemical composition of the core and, accordingly, to consider mainly the contribution of other factors, such as forests, forest fires, volcanic activity, the ocean, and sea ice. Ammonium (NH4+) and formate can be used as markers of bioproductivity of forests and forest fires. For these compounds, a certain periodicity of concentration fluctuations can be traced. However, the shallow depth of drilling does not allow us to identify the seasonality of these changes and, as a consequence, does not allow us to date the core. Based on the obtained results, the main markers of biomass burning (ammonium and formate), forest bioproductivity (ammonium, formate, acetate), and sea ice spreading (sodium and chloride ions) can be identified. The examination of space images and archival materials showed the expediency of dendrochronological studies in two areas - Esso and Kliuchevskii group (Ushkovskii). Esso - repeated gathering of samples for prolongation of the chronologies constructed in 1970-1990s. It will allow to estimate the stability of the climatic signal, found in these chronologies of the width of the rings of larch and spruce obtained earlier. On the basis of the new samples, optical density chronologies along the altitudinal profile will be constructed for the first time in Kamchatka to reveal the climatic signal, which is usually more clearly expressed in the ring density than in the width. Both locations will be surveyed to assess above-ground/completely woody biomass/bioproductivity dynamics over the past 100-200 years. For the first time, fire chronologies will be obtained in two locations: volcanic and non-volcanic areas. The lakes located in the glacial zone in the Middle Ridge, on the Kronotsky Peninsula, in the Kluchevskaya group of volcanoes and in the area of Shiveluch volcano were examined on the basis of space imagery materials. Given the transport accessibility, it is most expedient to focus on the latter two areas - Shiveluch volcano and the glaciers of the Klyuchevskaya group. A summary of historical and reconstructed explosive eruptions of Kamchatka volcanoes over the past thousand years, whose ash can be buried in the Ushkovsky volcano glacier, was compiled based on the literature and using weekly data from the Kamchatka Volcanic Eruption Response Team. In addition to the main sources, the summary also included major eruptions of the Stubel cone on Ksudach volcano (South Kamchatka), as well as the eruption of Maly Semyachik volcano. For some sites (Shiveluch, Avachinskii, and Malyi Semyachik), in addition to the list of historical eruptions, information on eruptions reconstructed by means of tephrostratigraphic and/or dendrochronological methods was given. The summary includes 206 eruptions, most of which are associated with two sites - Kliuchevskii volcano (66 eruptions from 1697 to 2021) and Bezymyannyi volcano (55 eruptions from 1955 to 2022). These volcanoes are located just over 10 km away from Ushkovsky volcano and may supply the greatest amount of tephra to the ice material. In contrast to Kliuchevskoi volcano, all eruptions of Bezymyannyi volcano are explosive, accompanied by ashfalls and have a high frequency. Twenty-two eruptions of Shiveluch volcano, one of the most active volcanic centers in Kamchatka, located 80 km north of the Ushkovskii Glacier, were included in the summary. The list of historical events includes two catastrophic eruptions in 1854 and 1964. Kizimen volcano (110 km southwest of Ushkovsky Glacier) has not had a high frequency of eruptions in the last thousand years, but ashfalls from its recent eruption in 2010-2013 spread over considerable distances, including towards Ushkovsky Volcano. Based on the information collected on the scale and nature of eruptions of the most active explosive volcanoes in Kamchatka, as well as available data on the direction of ash plumes distribution, the summary highlighted events whose ash could potentially be present in the glacier. The most extensively documented in the literature and open sources are the eruptions of the last 20 years, when satellite monitoring and video surveillance systems recorded the direction, extent, and area of ash plumes. For earlier historical eruptions, information on the spreading of ash plumes is extremely limited, and indirect evidence, such as references to ash plumes in settlements close to Ushkovskii volcano (Klyuchi, Maiskoye, and Kozyrevsk), was considered to highlight potential events. A total of 36 eruptions whose tephra could have been buried in the glacier were highlighted, including 11 events that occurred since the beginning of the current century.