Paleoenvironmental proxy records from Lake Hovsgol, Mongolia, and a synthesis of Holocene climate change in the Lake Baikal watershed

Here we discuss paleoenvironmental evolution in the Baikal region during the Holocene using new records of aquatic (diatom) and terrestrial vegetation changes from Hovsgol, Mongolia's largest and deepest lake. We reconcile previous contradictory Baikal timescales by constraining reservoir corrections of AMS dates on bulk sedimentary organic carbon. Synthesis of the Holocene records in the Baikal watershed reveals a northward progression in landscape/vegetation changes and an anti-phase behavior of diatom and biogenic silica proxies in neighboring rift lakes. In Lake Baikal, these proxies appear to be responsive to annual temperature increases after 6 ka, whereas in Lake Hovsgol they respond to higher precipitation/runoff from 11 to 7 ka. Unlike around Lake Baikal, warmer summers between 6 and 3.5 ka resulted in the decline, not expansion, of forest vegetation around Lake Hovsgol, apparently as a result of higher soil temperatures and lower moisture availability. The regional climatic proxy data are consistent with a series of 500-yr time slice Holocene GCM simulations for continental Eurasia. Our results allow reevaluation of the concepts of ‘the Holocene optimum’ and a ‘maximum of the Asian summer monsoon’, as applied to paleoclimate records from continental Asia.     

Secular evolution of the period and inclination of the magnetic to rotation axis and recycled pulsars

Statistical analysis has been carried out of the relations between period and the ageP–t _c, and the inclination of magnetic to rotation axis to the age –t _cof pulsars have been done.Up to characteristic agest _c=3×10⁷ years the period increases as expected for magneto-dipole radiation energy lossesP=P _m (1–exp(–t/ _B ))^1/n–1. Best-fitting parameters of this approximation are the time-scale of the magnetic moment decay _B =4×10⁶ years and breaking indexn=3.6. Fort _c>3×10⁷ years theP–t _cdependence is significantly different.The inclination of magnetic to rotation axis decreases versus age, showing a secular alignment of the axis. But this decrease continues also only up tot _c=3×10⁷ years. Thus bothP–t _cand –t _cdependencies indicate that most of the pulsars of agest _c>3×10⁷ years are not evolutionary continuations of more younger ones, but apparently represent another population of pulsars, which differ by their genetic history or physical processes. This population includes all known millisecond pulsars. We suggest, that this population is a so-called recycled pulsar. The list of candidates of recycled pulsars is presented.A new evaluation of the inclination of the magnetic to the rotation axis for 105 pulsars is presented.     

地下水储藏仓冻融过程的计算分析

Thawing and freezing processes are developed subsequently with filling of constructed- in-permafrost underground reservoirs with water. The paper proposes an approximate method to assess these processes with instant filling of reservoirs with water. This method is based on experimentally found mechanism of water cooling in underground reservoirs. Calculation results are given showing effects on the reservoir radius during thaw/freeze cycles, on water and soil temperature as well as on water storage duration.     

Geochemical Types of Granitoids of the Mongol—Okhotsk Belt and Their Geodynamic Settings

The following geochemical types of granitoids have been investigated in the Mongol-Okhotsk belt:tholetitic,palingenic calc-alkaline,latitic,plumasitic and arpaitic rare-metal granites.Plagiogranites of the tholeiitic series occur within the Mongol-Okhotsk suture,indicating a subduction environment.The calc-alkaline granitoids responsible for the batholith-like intrusions and their formation are related to collision environments.The latest granitoids of the latite series and rare-metal granites came into existence after the collision of continental masses,providing evidence of intraplate magmatism.     

Postglacial Vegetation and Climate History of the Oka Plateau (East Sayan Mountains,South Siberia)

Doklady Earth Sciences - The first results of palynological analysis of the bottom deposits of Kaskadnoe Lake and a reconstruction of vegetation and climate on the Oka Plateau over the last 14.2 ky...     

New approaches to laser desorption/ionization of chemical compounds for geochemical studies

Two new versions of surface-assisted laser desorption/ionization method are considered. One version is based on a combination of this method with thermal desorption sample injection and may be applied for determination of chemical compounds that are transformed into a gas phase without decomposition by heating. Another version is based on laser-induced electron-transfer desorption/ionization and could be used for determination of compounds with low proton affinity. The possibilities of the new approaches are illustrated by the example of determination of aminoacids, medical compounds, chlorophyll, as well as gold in sulfide ores.     

Detection of the polarized radio emission from the Crab Nebula

The radio emission that was observed in earliest times could not be interpreted in terms of thermal emission process. The suggestion that synchrotron radiation was observed required the confirmation by the detection of linear polarization. We have made such a detection in 1957 which we describe in the present article. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

More about Diring Yuriakh: Unsolved geoarchaeological problems at a “lower” paleolithic site in central Siberia

The geoarchaeology of Diring Yuriakh, perhaps the oldest firmly documented archaeological site in Siberia, at more than 260,000 years old, is important for modeling the peopling of Northern Asia and North America. This article focuses on some important details about the stratigraphy of the Diring site, which have previously only been published in Russian. There are two major geoarchaeological problems at Diring. First, the stratigraphic position of the layer containing the supposed pebble tools (relative to Middle Pleistocene sediments at the site) is not well defined. Second, there remains doubt as to the nature of the association between the majority of the Diring artifacts and the sediments dated to between ca. 267,000 and 366,000 years ago. Until these problems are resolved, the proposed Lower Paleolithic dating for the Diring site must be considered as provisional. © 1999 John Wiley & Sons, Inc.     

Paleoproterozoic Age (2055–2050 Ma) of Volcanogenic–Terrigenous Rocks from the Bilyakchan Zone of the Siberian Platform and Okhotsk Massif Junction

Doklady Earth Sciences - The age of the Bilyakchan Group, representing the northern fragment of the Ulkan–Bilyakchan volcano-plutonic belt of the Okhotsk Massif and Siberian platform junction...