The Glacier Complexes of the Mountain Massifs of the North-West of Inner Asia and their Dynamics

The subject of this paper is the glaciation of the mountain massifs Mongun-Taiga, Tavan-Boghd-Ola, Turgeni- Nuru, and Harhira-Nuru. The glaciation is represented mostly by small forms that sometimes form a single complex of domeshaped peaks. According to the authors, the modern glaciated area of the mountain massifs is 21.2 km2 (Tavan-Boghd-Ola), 20.3 km2 (Mongun-Taiga), 42 km2 (Turgeni- Nuru), and 33.1 km2 (Harhira-Nuru). The area of the glaciers has been shrinking since the mid 1960’s. In 1995–2008, the rate of reduction of the glaciers’ area has grown considerably: valley glaciers were rapidly degrading and splitting; accumulation of morainic material in the lower parts of the glaciers accelerated. Small glaciers transformed into snowfields and rock glaciers. There has been also a degradation of the highest parts of the glaciers and the collapse of the glacial complexes with a single zone of accumulation into isolated from each other glaciers. Reduced snow cover area has led to a rise in the firn line and the disintegration of a common accumulation area of the glacial complex. In the of the Mongun-Taiga massif, in 1995– 2008, the firn line rose by 200–300 m. The reduction of the glaciers significantly lagged behind the change in the position of the accumulation area boundary. In the past two years, there has been a significant recovery of the glaciers that could eventually lead to their slower degradation or stabilization of the glaciers in the study area

Present Glaciers and Their Dynamics in the Arid Parts of the Altai Mountains

This research is based on multiyear in-situ observations, analysis of satellite and aerial imagery, meteorological data, and mass balance index calculations. Presently, 659 glaciers cover a total area of 322.1 km2. We identified four favorable, two neutral, and five unfavorable longer intervals of glacier development since 1940. A decelerating of glacial retreat took place in the 1960s and in the late 1980s/early 1990s. The strong decline in glacial mass between 1995 and 2009 resulted in a fast reduction of the glacial area (0.9% year−1 on the northern slope of Tavan Bogd, 1.5% year−1 at Mongun-Taiga), mostly due to the degradation of small glaciers; after 2009, the glacial loss slowed down. Large valley glaciers behaved asynchronously until recently, when their retreat accelerated rapidly reaching in some cases over 40 m∙year−1. Degradation of the accumulation zone and separation of the debris-covered parts of the glaciers are characteristic for the glacial retreat in the region of research. The time of reaction of the fronts of four valley glaciers of Mongun-Taiga and the northern slope of Tavan Bogd on climatic fluctuations is estimated between 11 and 20 years. Over the next decade, high rates of glacial degradation are expected

Present Glaciers of Tavan Bogd Massif in the Altai Mountains, Central Asia, and Their Changes since the Little Ice Age

The Tavan Bogd mountains (of which, the main peak, Khuiten Uul, reaches 4374 m a.s.l.) are situated in the central part of the Altai mountain system, in the territories of Russia, Mongolia and China. The massif is the largest glacierized area of Altai. The purposes of this study were to provide a full description of the scale and structure of the modern glacierized area of the Tavan Bogd massif, to reconstruct the glaciers of the Little Ice Age (LIA), to estimate the extent of the glaciers in 1968, and to determine the main glacial trends, and their causes, from the peak of the LIA. This work was based on the results of long-term field studies and analysis of satellite and aerial data. At the peak of the LIA, Tavan Bogd glaciation comprised 243 glaciers with a total area of 353.4 km2. From interpretation of Corona images, by 1968 the number of glaciers had decreased to 236, with a total area of 242 km2. In 2010, there were 225 glaciers with a total area of 201 km2. Thus, since the peak of the LIA, the glacierized area of the Tavan Bogd mountains decreased by 43%, which is somewhat less than for neighboring glacial centers (i.e., Ikh-Turgen, Tsambagarav, Tsengel-Khairkhan and Mongun-Taiga mountains). The probable causes are higher altitude and the predominance of larger glaciers resistant to warming. Accordingly, the smallest decline in Tavan Bogd occurred in the basins of the Tsagan-Gol (31.7%) and Sangadyr (36.4%) rivers where the largest glaciers are located. In contrast, on the lower periphery of the massif, where small glaciers predominate, the relative reduction was large (74⁻79%). In terms of general retreat trends, large valley glaciers retreated faster in 1968⁻1977 and after 2010. During the 1990s, the retreat was slow. After 2010, glacial retreat was rapid. The retreat of glaciers in the last 50⁻60 years was caused by a trend decrease in precipitation until the mid-1970s, and a sharp warming in the 1990s and early 2000s

The Components of the Glacial Runoff of the Tsambagarav Massif from Stable Water Isotope Data

The aim of this study was to determine the contribution of snow and glacial ice to the river fluxes, and to identify the type of ice formation in the Tsambagarav massif (the northwestern part of Mongolia). The main method for this study was isotopic analysis of water samples. The isotopic separation showed that the shares of the main components in the total runoff differed for different rivers of the massif. Alongside with that, glacial meltwater prevailed in all the investigated fluxes. The share of snow and firn in the meltwater coming from the surface of the large valley glaciers in the middle of the ablation season in 2017 changed by only 10%—from 20% to 30%. Thus, further reduction of glaciation caused by global climate change could significantly affect the water balance of the study area. The isotopic composition of glacial ice proves that its alimentation primarily comes from precipitation during the transitional seasons. Superimposed ice is not the basis for nourishment of the glaciers of the Tsambagarav massif

Microclimate affects soil chemical and mineralogical properties of cold alpine soils of the Altai Mountains (Russia)

Purpose: The present work focuses on cold alpine soils of the Altai Mountains (Siberia, Russia). Permafrost is widespread and often occurs at a depth of about 100 cm. The area is characterised by extremely cold winters and cool summers: the aim was consequently to find out whether weathering could be more intense on thermally less unfavoured conditions or whether the abundance of water could be a more important factor. Materials and methods: We investigated 10 soils in a very small area close to a local glacier tongue. Five of the investigated soils were south-facing and the other five north-facing. The soils have the same parent material (mica-rich till), altitude, topography and soil age. The vegetation is alpine grassland that is partially intersected with some juniper and mosses. Soil chemical properties such as organic C, N, soil organic matter quality (using DRIFT), pH value, (oxy)hydroxides, total elemental contents (XRF) and soil micromorphology and mineralogy (using diagnostic treatments and XRD) were determined. The age constraint of the site was given by geomorphic studies together with 14C dating of a nearby peat bog and the stable organic matter fraction of the soils. Results and discussion: The soils have a Holocene age. The results showed astonishingly clearly—similarly to the European Alps—that the north-facing soils have a higher weathering state. This is expressed by lower pH values, higher oxalate and dithionite extractable Fe, Al, Mn and Si contents, higher C and N concentrations and stocks when compared to the south-facing sites. No statistically significant differences with respect to weathering indexes could be detected. The geochemical evolution of the soils seems to be enhanced at north-facing sites, even though very severe climatic conditions prevail. Furthermore, biodegradation seems to be less pronounced on north-facing compared to south-facing sites as poorly degraded organic matter is accumulated. This gives rise to more organic ligands that promote metal binding and their subsequent eluviation along the soil profile. Conclusions: We consequently must assume that weathering is not limited by low temperatures in the active layer but is rather controlled by soil moisture that seems to be higher during the warmer period in the north-facing soils