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...     

Post-processing and forecasts updating in automated systems of flash flood forecasting

This paper completes the series of three articles devoted to automated forecasting of flash floods [3, 5] and describes an effective approach of forecast updating through post-processing operations, which can be useful only in conjunction with such fast and efficient real-time re-calibration algorithms as SLS-based methods are. In particular, a proposed methodology is aimed to reduce negative consequences of scarce or low-quality data that can corrupt optimized parameters and, therefore, lower forecasting efficiency. A new modification of SLS-based optimization that supposes simultaneous re-calibration of the model and correction of the model input by generating of ensemble noises (SLS-E) is presented.     

Late Paleozoic and Early Mesozoic rare-metal magmatism of Central Asia: Stages, provinces, and formation settings

Late Paleozoic and Early Mesozoic epochs in the formation history of the Central Asian Foldbelt are distinguished by high rare-metal productivity. A number of large REE, Ta, Nb, Zr, Be, Sn, Li, Mo, Re, and other deposits were formed at that time. As a rule, they are of the magmatic origin and related to the intrusions of highly evolved igneous rocks varying in composition from alkaline ultramafic with carbonatites to alkali and Li-F granites. In general, the occurrences of rare-metal magmatism are related to the rift zones of the Central Asian Rift System formed 310?C190 Ma ago and conjugated with a consecutive series of the Barguzin, Hangay, and Hentiy zonal igneous provinces characterized by the large batholiths in their centers and rift zones in the framework. Such a structure indicates that these provinces were formed above isometric mantle sources or plumes with participation of large-scale crustal anatexis. The evident links of rare-metal deposits to occurrences of mantle magmatism within the zonal igneous provinces show that plume sources played an important role in their formation.     

Detection of the new rotating radio transient pulsar PSR J2225+35

We have detected the new pulsar PSR J2225+35, which displays the properties of the new class of radio sources “Rotating Radio Transients” (RRATs). RRATs are distinguished by isolated bursts of radio emission and long quiet periods. Throughout 45 observations with a total duration of about 3 hr, only two bursts of radio emission lasting a total of about 10 min were detected in two observations. The temporal and frequency delay of the pulses corresponds to the dispersion measure DM = 51.8 pc/cm³ and the distance d = 3.05 kpc. The period of the pulses is P = 0.94 s. The emission is polarized, with the rotation measure being RM = 49.8 rad/m².     

Siberian meimechites: origin and relation to flood basalts and kimberlites

Here we combine petrological-geochemical and thermomechanical modeling techniques to explain origin of primary magmas of both Maimecha–Kotui meimechites and the Gudchikhinskaya basalts of Norilsk region, which represent, respectively, the end and the beginning of flood magmatism in the Siberian Trap Province.We have analyzed the least altered samples of meimechites, their olivine phenocrysts, and melt inclusions in olivines, as well as samples of dunites and their olivines, from boreholes G-1 and G-3 within the Guli volcanoplutonic complex in the Maimecha–Kotui igneous province of the northern Siberian platform. The Mn/Fe and Ni/MgO ratios in olivines indicate a mantle peridotite source of meimechites. Meimechite parental magma that rose to shallow depths was rich in alkalis and highly magnesian (24 wt.% MgO), largely degassed, undersaturated by sulfide liquid and oxidized. At greater depths, it was, likely, high in CO₂ (6 wt.%) and H₂O (2 wt.%) and resulted from partial melting of initially highly depleted and later metasomatized harzburgite some 200 km below the surface. Trace-element abundances in primary meimechite magma suggest presence of garnet and K-clinopyroxene, in the mantle source and imply for genetic link to the sources of the early Siberian flood basalts (Gudchikhinskaya suite) and kimberlites. The analyzed dunite samples from the Guli complex have chemistry and mineralogy indicating their close relation to meimechites.We have also computed thermomechanical model of interaction of a hot mantle plume with the shield lithosphere of variable thickness, using realistic temperature- and stress-dependent visco-elasto-plastic rocks rheology and advanced finite element solution technique.Based on our experimental and modeling results we propose that a Permian–Triassic plume, with potential temperature of about 1650 °C transported a large amount of recycled ancient oceanic crust (up to 15%) as SiO₂-supersaturated carbonated eclogite. Low-degree partial melting of eclogite at depths of 250–300 km produced carbonate-silicate melt that metasomatized the lithospheric roots of the Siberian shield. Further rise of the plume under relatively attenuated lithosphere (Norilsk area) led to progressive melting of eclogite and formation of reaction pyroxenite, which then melted at depths of 130–180 km. Consequantly, a large volume of melt (Gudchikhinskaya suite) penetrated into the lithosphere and caused its destabilization and delamination. Delaminated lithosphere that included fragments of locally metasomatized depleted harzburgite subsided into the plume and was heated to the temperatures of the plume interior with subsequent generation of meimechite magma. Meimechites showed up at the surface only under thicker part of the lithosphere aside from major melting zone above because otherwise they were mixed up in more voluminous flood basalts. We further suggest that meimechites, uncontaminated Siberian flood basalts and kimberlites all shear the same source of strongly incompatible elements, the carbonated recycled oceanic crust carried up by hot mantle plume.     

The topical problems of identifying the results of the observations in recent geodynamics

The paper addresses the problems of identifying the results of deformational observations on the Earth, which arise from the new measurement technologies and lead to the ambiguity relationships such as the “spatial size of the anomaly—density of the observation sites” and the “duration of the anomalies—degree of temporal detail of the measurements.” It is found that many “paradoxical” conclusions concerning the rates and scales of the recent geodynamical processes are removed if the parameters of the measurement system match the properties of the studied object and if the relative character of the observational means is taken into account. It is shown that the time variation in the uniaxial deviatoric stress leads to the variation in the volumetric strain and, consequently, to the variation in gravity. The ambiguity in determining the ground displacement vectors by SAR interferometry is demonstrated. It is concluded that the autonomous use of the interferometry data leads to the significant distortions of the results, and these data should be necessarily used in combination with the ground-based geodetic observations.     

The Convergence Space Experiment: Remote Determination of the Sea Surface Temperature via Radio Measurements at Frequencies of 10.65, 18.7, and 36.5 GHz

Izvestiya, Atmospheric and Oceanic Physics - A regression approach is presented for the problem of restoring the sea surface temperature (SST) from radiometric measurements of a microwave...     

Preliminary Characterisation of New Reference Materials for Microanalysis: Chinese Geological Standard Glasses CGSG‐1, CGSG‐2, CGSG‐4 and CGSG‐5

Four silicate glasses were prepared by the fusion of about 1 kg powder each of a basalt, syenite, soil and andesite to provide reference materials of natural composition for microanalytical work. These glasses are referred to as ‘Chinese Geological Standard Glasses’ (CGSG) ‐1, ‐2, ‐4 and ‐5. Micro and bulk analyses indicated that the glasses are well homogenised with respect to major and trace elements. Some siderophile/chalcophile elements (e.g., Sn, Pt, Pb) may be heterogeneously distributed in CGSG‐5. This paper provides the first analytical data for the CGSG reference glasses using a variety of analytical techniques (wet chemistry, XRF, EPMA, ICP‐AES, ICP‐MS, LA‐ICP‐MS) performed in nine laboratories. Most data agree within uncertainty limits of the analytical techniques used. Discrepancies in the data for some siderophile/chalcophile elements exist, mainly because of possible heterogeneities of these elements in the glasses and/or analytical problems. From the analytical data, preliminary reference and information values for fifty‐five elements were calculated. The analytical uncertainties [2 relative standard error (RSE)] were estimated to be between about 1% and 20%.     

Detection of giant pulses from the pulsar PSR B1112+50

We detected giant pulses from the pulsar PSR B1112+50. A pulse with an intensity that is a factor of 30 or more higher than the intensity of the average pulse is encountered approximately once in 150 observed pulses. The peak flux density of the strongest pulse is about 180 Jy. This value is a factor of 80 higher than the peak flux density of the average pulse. The giant pulses are narrower than the average profile by approximately a factor of 5 and they cluster about the center of the average profile.