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X-ray fluorescence scanning with synchrotron radiation was performed to study sediment core records of floods in Amur Bay, Sea of Japan. Interlayers of 3–8 mm with abnormally low bromine content were formed by the Razdolnaya River discharge to the central part of the bay during extreme floods, accompanied by severe storms at sea. Such conditions in the region are typical for periods of deep tropical cyclones (typhoons), to which the distinguished interlayers were compared on the timescale. This approach was made possible thanks to the high rate of sedimentation in the bay (3–5 mm/a) and low bioturbation of sediments under anoxic conditions.

We study a unique deposit of Nb-REE ores that occur as three orebodies overlying weathered rocks of the Tomtor ultramafic alkaline-carbonatite complex in the northern Sakha Republic (Yakutia). The formation conditions of the rich Tomtor ores remain poorly constrained. Our hypothesis is that these ores, composed of detrital and authigenic minerals, were deposited in a hydrothermal lake. The Eh-pH parameters of water are reconstructed from REE distribution in ores and in monazite, with reference to results of thermodynamic calculations. The stability fields of hydrous Ce, La, and Nd phosphates in the Pourbaix diagrams are proximal in a region within a small range of pH (4-6) and Eh (-0.25 -+0.25 V). Monazite apparently formed by dehydration of the precursor phase of hydrous REE phosphate. This inference is supported by coexistence of Fe 3+ and Fe 2+ minerals.

The glacial lake Kucherla is located in the Altai Mountains at an altitude of 1790 meters above sea level. We use the 112 cm core obtained in March 2018 from the deepest part of the lake (45 m) for the study. In the process of coring, special attention was paid to the preservation of the upper layers of the bottom sediment (water - sediment boundary). Bottom sediments of the lake contain visual layers with a thickness of 1-3 mm. We count the layers using photographs of the optical sections. Counting the layers and comparing with the intensity distribution of the Cs-137 and Pb-210 isotopes show the annual (varve) nature of their origin. The data obtained is used to create an age model of high accuracy and reliability. An age scale of annual layer thickness over the past century was built. This makes it possible to create a model of the annual cycle of sedimentation and to establish a connection with changing meteorological parameters. The model will also show a relationship with the dynamics of the glacier supplying terrigenous material to the lake.

To better understand past climate variability of vast terrestrial regions, reconstructions of different climate parameters are needed. Different types of climate proxy data may provide season-, time resolution-, and longevity-specific information. In this paper, we present a reconstruction of summer temperature and ablation of Malii Aktru glacier variability, Altay Mountains, for the past four centuries inferred from lake Teletskoe sediments and the maximum density of the tree-rings of Siberian larch trees found at the upper timberline. The Teletskoe lake is situated close to both the Malii Aktru glacier and the tree-ring-maximum-density-chronology site (approxinately 50.29N, 87.39E). Lake Teletskoe sediments provided seasonal climatic information for the late Holocene, especially regarding summer and annual temperature variations. Ablation of the Malii Aktru glacier was also clearly sensitive to summer temperature (correlation was 0.8; p=0.05; n=32). The tree-ring maximum density chronology was well correlated with summer temperature (r=+0.65-0.72; n = 60). Ablation of Malii Aktru glacier was reconstructed using the linear regression from the tree-ring maximum density chronology (r=+0.68; n=32; p=0.05 for the calibration period) for the period since '60' AD. The summer temperature reconstructed from the data on the lake sediments was compared with the reconstructed ablation of Malii Aktru glacier for 1601-1994. A common low-frequency variability (100-200-year long cycles) was identified in the summer temperature and ablation for the reconstructed series. For example, a decrease in ablation of Malii Aktru coincided well with a temperature decrease that was found around 1700 AD and middle of 1850AD. The cold periods during LIA (Little Ice Age) were clearly pronounced in Altai Mountains climate reconstructions obtained from different climate proxies. Our study showed that various sources (tree-rings, glaciers and lake sediments) may be based upon to extract common information on climate low frequency variables, which helps better understand regional climate changes.

We analyzed the dynamics of Lake Teletskoye water level and attempted to use data on bottom sediment geochemistry in combination with Siberian larch (Larix sibirica) tree-ring width chronology to reconstruct it for late Holocene. In particular, we studied the links among the water level characteristics, precipitation amount, bottom sediment geochemistry, and tree-ring width chronology available for Russian Altai. A correlation analysis revealed the annual water level fluctuations to correlate closely with mean annual temperature and annual precipitation (67% and 33%, respectively). The fluctuations exhibited a negative correlation with the regional tree-ring width chronology. As for the bottom sediments, two components were identified, one of which correlated closely with air temperature and the other with precipitation. Combining these three components, including tree-ring width chronology, provides new possibilities for a complex reconstruction of the lake water level fluctuations occurred during middle and late Holocene based on a regression model. A regression reconstruction model of the dynamics of the Lake Teletskoye water level was calculated for the last millennium. We defined ~60-, ~100-, ~200-year cycles of water level variability in Teletskoye Lake and supposed that the observed fluctuations are due to long-term climatic changes. Of the greatest interest are the identified interdecadal and decadal climate-caused water level fluctuations, since they will enable to estimate indirectly, in the long term, climatic changes in southern Siberia for the past 2-5 thousand years.

A solar-terrestrial relations were examined, using millennium-scale paleoclimatic data from the Central Asia mountain region. The paleoclimatic data were based on non-varved lake sediments of the Teletskoye lake and temperature-sensitive long tree-ring width chronologies from the Altai region (Altai Mountains, South Siberia, Russia) in the late Holocene (2000 years). Also, a solar-activity during late Holocene was used to analyze. Core of the bottom sediments from the Teletskoe lake (Altai Mountains) were investigated, using scanning X-ray fluorescent analysis method with synchrotron radiation (spatial resolution is 0.1 mm). A method ensemble empirical mode decomposition was used, to extract low-frequency variability from all presented paleoarchives. The results obtained for paleodata indicate palaeoclimatic oscillations in the range of the de Vries (Suess) ( similar to 200-year) solar cycles through the late Holocene. Evidence of the influence of solar activity on global climatic processes and terrestrial ecosystems, is discussed.

Now investigation of environmental dynamics is focusing to study high resolution - annual and seasonal time series. But annual quantitative reconstructions by lake deposits are scarce because discrete sampling and analysis. The new approach to study sediment records appeared due to scanning microanalysis of cores in situ. X-ray fluorescence analysis on synchrotron radiation in the Institute of Nuclear Physics, Novosibirsk, appeared to be the most effective. Sub-millimeter layered structures of bottom sediments from Siberian lakes as well as tree ring series in surrounded areas are studied. Elements composing organic component of sediments are usually responding to temperature. And elements from clastic mineral part more reflect annual precipitation and runoff. On this base air temperature, precipitation and lake level are restored on annual scale for the last two millennia. Climate variability reconstructed by geochemistry of lake sediments and dendrochronology reveals similar trends. Availability of several basic series of geochemical indices extends the scope for quantitative reconstructions of sought quantity.

The method of analytical microstratigraphy of lacustrine sediments allows to obtain paleoclimatic information fundamentally and new quality was tested on a model object -- Lake Teletskoe. In this paper, the Teletskoe lake bottom sediments were studied by scanning X-ray microprobe using synchrotron radiation from VEPP-3 with an annual time resolution on the time interval of 1,500 years. Data on the distribution of isotopes Cs-137, Pb-210, C-14 were used to create an age model. Using this model, the authors constructed time series of sediment cores composition changes. At each point of the core, they determine the content of more than 20 trace elements. Terrigenous elements reflect changes in precipitation in the catchment, while Organogenic elements are more associated with regional temperature changes. The ratio of Rb/Sr shows the size of the particles and associated with spring flooding dynamics. The resulting time series were processed by mathematical methods, including the Hilbert-Huang transformation.

A sediment column of 155 cm in length was retrieved by hammer corer in the deepest central part of lake Shira. Solid samples were prepared from the wet cores by freeze drying and impregnating with epoxy resin. The inter annual and inter seasonal variations in the trace element composition of annual layers are studied by means of X-ray scanning microanalysis with synchrotron radiation on the VEPP-3 and BESSY-II storage rings. Detailed experimental investigations of the internal structure of annual layers allowed the authors to create a lithological-geochemical model of sedimentation in Lake Shira, and to find climatically correlated minor elements. This model of the annual cycle of sedimentation was used to explain the periodic white layers with high Sr contents in the core. Thick 3 cm-5 cm light carbonate Sr-enriched intervals correspond to an extremely low level of the lake and are repeated every 450-550 years.

Geochemical study of bottom sediments from several Siberian and Mongolian lakes allows reconstructing of environmental parameters such as air temperature, precipitation, lake level, runoff, tree ring growth index, pressure, wind direction and others on annual scale. The new approach to study sediment records appeared due to automatic technique for scanning microanalysis of cores in situ. X-ray fluorescence analysis on synchrotron radiation in the Institute of Nuclear Physics, Novosibirsk was adapted. Elements composing organic component of sediments are correlative with mean annual temperature variations because of changes vegetation productivity content in catchment and in waterbody. And elements from clastic mineral part reflect annual precipitation, runoff and the proportion of the unweathered terrestrial fraction. X-ray density indicates water yield regime and sediment flux. Analysis shows graded structure from lower mid-grained material to upper fine-grained part as usual. Equilibrium thermodynamic modeling allows to quantify the atmosphere-water-sediment-pore solution system for saline lakes.