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Harzburgitic xenoliths cut by pyroxenite veins from Avachinsky volcano, Kamchatka, are derived from the sub-arc mantle and record element transfer from the slab to the arc. Olivine and orthopyroxene in the harzburgites have Li isotopic compositions (δ7Li = +2.8 to +5.6) comparable to estimates of the upper mantle (δ7Li ~ +4 ± 2). The pyroxenite veins, which represent modal metasomatism and may therefore provide information about the metasomatic agent, have mantle-normalized trace element characteristics that suggest overprinting of their mantle source by an aqueous, slab-derived fluid. These include relative enrichments of Pb over Ce, U over Th and Sr over Nd. Li is enriched relative to the HREE, and ortho- and clinopyroxene from the veins are in Li elemental and isotopic equilibrium with each other and the surrounding harzburgite. Vein samples (δ7Li = +3.0 to +5.0) do not record a significant slab-derived δ7Li signature. These observations can be reconciled if slab Li diffusively re-equilibrates in the mantle wedge. Modeling demonstrates that Li equilibration of small (1–2 cm width) veins or melt conduits is achieved at mantle wedge temperatures within 101–105 years. We conclude that strongly fractionated Li isotopic signatures cannot be sustained for long periods in the sub-arc mantle, at least at shallow (<70 km) depths. [ABSTRACT FROM AUTHOR]

Neutrons have always been produced by spallation reactions with the high energy beams hitting various targets at CERN, but it was not before 2000 that neutrons were produced on purpose for experiments related to problems in nuclear astrophysics and technology. Initiated by Carlo Rubbia and his colleagues [1] and supported as a European project [2] the construction of n_TOF facility started in 2000. In parallel, the n_TOF Collaboration was established with about 120 participants from more than 30 institutes, mostly from the EU, but also from the United States and Russia, to build the experimental equipment for neutron cross-section measurements and to prepare the first measurement campaign from 2002 to 2004. The main goal of the n_TOF project was “to produce, evaluate and disseminate cost-effectively neutron induced reaction cross sections for isotopes relevant to the Stellar Nucleosynthesis, to Nuclear Physics and to the concept for an Accelerator Driven System. In total, 40 fission and capture cross-sections in the mass range between 24Mg and 245Cm have been successfully measured during the first campaign. Presently, the n_TOF Collaboration is preparing for the second campaign 2009-2012 after the facility was refurbished and after a new spallation target has been installed. [ABSTRACT FROM AUTHOR]

Abstract: The first detailed isotope-geochemical study of carbonate deposits has been performed in the Lower Famennian stratotype section of the northwestern Kuznetsk Basin (Kosoy Utyos), which was localized in the middle latitudes of the Northern Hemisphere in the Late Devonian. The δ13Ccarb, δ13Corg, and δ18O variation curves were constructed for the section deposits. Geochemical and petrographic studies of carbonates allowed allocation of samples that underwent postsedimentation alteration and exclude them from further interpretation. Compared with coeval sections in the other world''s regions, the Kosoy Utyos section is characterized by higher δ13Ccarb values, up to 5.4‰, whereas the maximum value in subequatorial area sections is 4‰. The isotope shift amplitude of the studied section reaches 4.6‰, which is 1.5‰ higher than those in other regions. The δ18O values are 3‰ lower than the ones of the world''s coeval sections. The results obtained show that δ13C and δ18O variation trends differ from those of coeval subequatorial sections. The high shift amplitude and maximum δ13Ccarb values in the Kosoy Utyos section are due to the shallow-water carbonate sedimentation environments on the Siberian continental shelf and, probably, the lower temperatures of waters in the middle latitudes as compared with the subequatorial areas. [Copyright &y& Elsevier]

[Display omitted] • The authors have recognized four species of intrusion-hosted deposits: gold-telluride, gold-tetradymite, gold-stibnite, and gold-bismuth-sulfosalt. • Intrusion-hosted gold deposits were formed during the two orogenic stages of the East Sayan geodynamic evolution: Neoproterozoic (860–850 Ma) and Early Paleozoic (458–439 Ma). • The different gold-associated mineral assemblages are interpreted by geochemically different parental granitoid intrusions. Our paper reviews a series of relatively low-grade gold deposits and prospects hosted by granitoid intrusions within the southeastern East Sayan in the Altaid Belt (northern Central Asian Orogenic Belt, Russia). The studied deposits/prospects are characterized by the presence of Te-, Sb- and Bi-bearing minerals. However, they differ in their main gold-associated mineral assemblages, which permits to distinguishing four mineralization assemblages: 1) gold-telluride; 2) gold-tetradymite; 3) gold-stibnite; and 4) gold-bismuth sulfosalt. The gold-telluride mineralization (1) is represented by the Tainskoye deposit, and the Khoringolskoye and Sagangolskoye prospects which are defined by paragenesis of native gold with Au-Ag-Bi-Pb-Ni tellurides, such as hessite, petzite, altaite, wehrlite, calaverite, melonite, altaite, and tellurobismuthite. The gold-tetradymite mineralization (2) which is represented by the Konevinskoye deposit, is hosted by the Saylag granitoid pluton, and contains tetradymite as one of the principal minerals associated with native gold. The gold-stibnite mineralization (3), represented by the Tumannoye prospect, is also hosted in a granitoid complex consisting of granodiorite and leucogranite. The gold-bismuth-sulfosalt mineralization (4) is documented at the Pogranichnoye prospect, where native gold is associated with the bismuth-bearing minerals: bismuthinite, galeno-bismuthite, lillianite, and native bismuth. Estimated δ18O values of ore-forming fluids from intrusion-hosted deposits range from 5.7 to 7.4‰, indicative of a magmatic origin; δ34S values of sulfides vary from −4.2 to 4.5‰, which corresponds to magmatic sulfur. The geological setting, element geochemistry of host granitoids, stable isotope ratios, and mineralogy of the studied deposits are consistent with a magmatic origin of the mineralizing fluids. The studied deposits are spatially associated with either Neoproterozoic or Early Paleozoic granitoids, belonging to the two main orogenic stages of the East Sayan geodynamic evolution. At ∼850 Ma, during the Neoproterozoic stage, deposits with dominant gold-telluride assemblages, formed in association with granitoids characterized by geochemical features of island arc granites. During 458–439 Ma, in the Early Paleozoic stage, gold-tetradymite, gold-stibnite, gold-telluride and gold-bismuth-sulfosalt assemblages were formed that are spatially associated with orogenic granites with different geochemical compositions. Most gold-bearing mineral assemblages are intersected by post-mineral Late Paleozoic dykes. The origin of these different gold-sulfide-telluride assemblages is explained with their genetic association with granitoid intrusions of different ages and compositions. [ABSTRACT FROM AUTHOR]

Abstract: Isotope dating of ultrapotassic magmatism in the central Chukchi region was carried out. Based on the Rb-Sr isochron age of monzonites from the Linkor stock (107±2.2. Ma) and using earlier obtained geochronological isotope data, we have estimated the time of one of the stages of ultrapotassic magmatism, 107–113 Ma. Igneous rocks of this age occur throughout the central Chikchi region, which suggests their genetic relationship with some great geodynamic event there, likely, the accretion of the Mainit island arc to the Chukchi microcontinent. The results obtained permit the reconstruction of the geologic history of the region and can be used to construct more detailed geodynamic models. [Copyright &y& Elsevier]

Abstract: The Re–Os distribution and isotopic composition have been studied within different ore facies, host-rocks and sediments from the Alexandrinka volcanogenic hydrothermal massive sulphide deposit, Southern Urals, Russia. The osmium contents increase and the initial 187Os/188Os isotopic compositions decrease in the ore facial range: sulphide chimneys–stockwork zone–seafloor massive and clastic sulphides–metalliferous sediments. This range reflects variable degrees of reduced hydrothermal fluid–oxidized seawater mixing during the hydrothermal ore-forming process. The Os isotopic composition of the hydrothermal sulphide chimney (187Os/188Os=1.3) is estimated to be a minimum value of the Devonian hydrothermal fluid, which is an intermediate between initial Os isotopic compositions of island-arc volcanics and interlayered sediments. The initial Os isotopic composition of metalliferous sediments (187Os/188Os ∼0.17–0.2) possibly reflects that of the Devonian seawater. The low rhenium concentrations in metalliferous sediments (about 1–2 ppb) could indicate oxic formation conditions. The Re–Os isotope data define a best-fit line corresponding to a Late Devonian age of 355±15 Ma (2σ) with initial 187Os/188Os of 0.12±0.19. This age could indicate a late Os isotope reequilibration due to ongoing hydrothermal fluid flow from the Givetian (stratigraphic age ∼375 Ma) until the closure of the Ural paleoocean in the Late Devonian. The Os contents are higher and Re/Os ratio is lower within Palaeozoic island-arc hosted Urals VHMS deposits compared with TAG deposit in MOR setting. [Copyright &y& Elsevier]

The concentration, radiocarbon (14C) and stable isotope (13C and 18O) content of CO have been determined in air samples collected across Russia (about 8,500 km) and along the Ob river during the summer of 1999 to study the CO sources and sinks. An instrumented carriage on the Trans-Siberian railway and a boat on the river Ob were used as atmospheric measurement platforms. In general, CO mixing ratios, CO stable isotope ratios, as well as the abundances of 14CO over West Siberia were similar to those found at remote northern hemispheric baseline monitoring stations. Identified sources of CO along the Ob appear to be connected to methane oxidation based on an inferred δ13Csource = −36.8 ± 0.6‰, while the value for δ18Osource = 9.0 ± 1.6‰ identifies it as burning. Thus flaring in the oil and gas production can be supposed to be a source. The extreme 13C depletion and concomitant 18O enrichment for two of the boat samples unambiguously indicates contamination by CO from combustion of natural gas (inferred values δ13Csource = −40.3‰ and δ18Osource = 17.5‰). For these two samples, that have strongly elevated 14CO concentrations, the industrial area near Tomsk is identified as a source area using meteorological calculations. Along the Trans-Siberian Railroad background CO was to various degrees contaminated with CO from methane combustion (δ13Csource = −35.7 ± 6.2‰ and δ18Osource = 10.3 ± 1.8‰). The impact of industrial burning was discernable in the vicinity of Perm-Kungur. [ABSTRACT FROM AUTHOR]

Covering a vast area of the northern Siberian platform are the Siberian flood basalts (SFB), which make up one of the world’s largest magmatic provinces. Along the northeastern margin of the SFB province lies the Maymecha-Kotuy alkaline-ultramafic complex, consisting of a large volume of alkaline lavas, numerous dykes, and the Guli massif together with numerous other, smaller alkaline plutons. The genetic link between the SFB and the Maymecha-Kotuy complex continues to be a subject of active debate. Although the rocks in both units have essentially the same age close to the Permian-Triassic boundary, questions remain as to the relative order of emplacement and the contributing source materials of each lithology. This study builds upon earlier petrologic, geochemical, and isotopic work to further an understanding of the relationship between SFB and alkaline rocks. A whole-rock U-Pb age of 250 ± 9 Ma was determined for the Guli massif, which lies within the range of ages previously reported for the SFB. The Pb isotopic composition of the Guli rocks plot mainly in the lower portion of the OIB field, and dunite and carbonatite extend downward into the MORB field suggesting for them a more depleted source than the one that produced the SFB. The combined Pb, Sr, and Nd isotopic systematics of the SFB and the Guli alkaline rocks enable the identification of several discrete source components. The first component dominates many of the Guli rocks and is characterized by low 87Sr/86Sr (0.7031 to 0.7038), high εNd (+5.35 to +3.97), and relatively unradiogenic Pb (206Pb/204Pb = 17.88–18.31; 207Pb/204Pb = 15.38–15.46; 208Pb/204Pb = 37.33–37.70), which we associate with the depleted (MORB source) mantle. The second component representing most of the SFB demonstrates a notable chemical and isotopic uniformity with 87Sr/86Sr values of 0.7046 to 0.7052, εNd values of 0 to +2.5, and an average Pb isotopic composition of 206Pb/204Pb = 18.3, 207Pb/204Pb = 15.5, and 208Pb/204Pb = 38.0. This component, making up the majority of SFB, is speculated to be a relatively primitive lower mantle plume with a near-chondritic signature. Contamination by upper and lower continental crustal material, designated as components 3 and 4, is postulated to explain the isotopic characteristics of some of the higher SiO2 Guli rocks and SFB. Finally, metasomatic processes associated with the invasion of the Siberian super-plume add a fifth component responsible for the extreme enrichment in rare-earth and related elements found in some Guli rocks and SFB. [ABSTRACT FROM AUTHOR]

Permafrost soils are an important reservoir of carbon (C) in boreal and arctic ecosystems. Rising global temperature is expected to enhance decomposition of organic matter frozen in permafrost, and may cause positive feedback to warming as CO2 is released to the atmosphere. Significant amounts of organic matter remain frozen in thick mineral soil (loess) deposits in northeastern Siberia, but the quantity and lability of this deep organic C is poorly known. Soils from four tundra and boreal forest locations in northeastern Siberia that have been continuously frozen since the Pleistocene were incubated at controlled temperatures (5, 10 and 15°C) to determine their potential to release C to the atmosphere when thawed. Across all sites, CO2 with radiocarbon (14C) ages ranging between∼21 and 24 ka bp was respired when these permafrost soils were thawed. The amount of C released in the first several months was strongly correlated to C concentration in the bulk soil in the different sites, and this correlation remained the same for fluxes up to 1 year later. Fluxes were initially strongly related to temperature with a mean Q10 value of 1.9±0.3 across all sites, and later were unrelated to temperature but still correlated with bulk soil C concentration. Modeled inversions of Δ14CO2 values in respiration CO2 and soil C components revealed mean contribution of 70% and 26% from dissolved organic C to respiration CO2 in case of two permafrost soils, while organic matter fragments dominated respiration (mean 68%) from a surface mineral soil that served as modern reference sample. Our results suggest that if 10% of the total Siberian permafrost C pool was thawed to a temperature of 5°C, about 1 Pg C will be initially released from labile C pools, followed by respiration of∼40 Pg C to the atmosphere over a period of four decades. [ABSTRACT FROM AUTHOR]

Abstract: The Sr, Nd and Pb isotopic compositions for the Kovdor phoscorite–carbonatite complex (PCC), Kola Peninsula, NW Russia, have been determined to characterize the mantle sources involved and to evaluate the relative contributions of a plume and subcontinental lithospheric mantle in the formation of the complex. The Kovdor PCC is a part of the Kovdor ultramafic–alkaline–carbonatite massif, and consists of six intrusions. The initial isotopic ratios of the analyzed samples, calculated at 380 Ma, display limited variations: ε Nd, +2.0 to +4.7; 87Sr/86Sr, 0.70319 to 0.70361 (ε Sr, −12.2 to −6.2); 206Pb/204Pb, 18.38 to 18.74; 207Pb/204Pb, 15.45 to 15.50; 208Pb/204Pb, 37.98 to 39.28. The Nd and Sr isotope data of the Kovdor PCC generally fit the patterns of the other phoscorites and carbonatites from the Kola Alkaline Province (KAP), but some data are slightly shifted from the mixing line defined as the Kola Carbonatite Line, having more radiogenic 87Sr/86Sr ratios. However, the less radiogenic Nd isotopic compositions and negative Δ7/4 values of Pb isotopes of the analyzed samples exclude crustal contamination, but imply the involvement of a metasomatized lithospheric mantle source. Isotopic variations indicate mixing of at least three distinct mantle components: FOZO-like primitive plume component, EMI-like enriched component and DMM-like depleted component. The isotopic nature of the EMI- and DMM-like mantle component observed in the Kovdor samples is considered to be inherited from metasomatized subcontinental lithospheric mantle. This supports the previous models invoking plume–lithosphere interaction to explain the origin of the Devonian alkaline carbonatite magmatism in the KAP. [Copyright &y& Elsevier]

Abstract: Element concentrations, element ratios and Pb and Zn isotope data are reported for different geologic samples (barren and ore-bearing granites and host rocks), technogenic products (ore concentrates and tailings) and biologic samples (lichens and birch leaves) from the Orlovka–Spokoinoe mining district, Eastern Transbaikalia, Russia, with the aim to trace the sources of Pb and Zn at a local level within the mining site. Lichens and birch leaves were used as receptors of contamination within the mining site. Pb/Zr and Zn/Zr values indicated Pb and Zn enrichment relative to host rocks. Zn isotope data of 15 geologic and 11 lichen samples showed different Zn isotopic signatures with the total range for the geologic suite of −0.4‰ to +1.2‰ and for lichens of +0.4‰ to +1.4‰ in δ 66Zn relative to Lyon JMC Zn standard. The source of isotopically heavy Zn within the Orlovka–Spokoinoe mining site could be potentially associated with long-range atmospheric aerosols that also contributed Pb to the studied mining site. Our results demonstrated that Zn isotopes might be used as new tools for Zn source assessment. [Copyright &y& Elsevier]

Lake-level changes inferred from seismic surveying and core sampling of the floor of Lake Baikal near the Selenga River delta can be used to constrain regional climatic history and appear to be correlated to global climate changes represented by marine oxygen isotope stages (MIS). The reflection pattern and correlation to the isotope stages indicate that the topset and progradational foreset sediments of the deltas formed during periods of stable lake levels and warm climatic conditions. During warm stages, the lake level was high, and during cold stages it was low. The drop in the lake level due to cooling from MIS 5 through MIS 4 is estimated to be 33–38 m; from MIS 3 through MIS 2, it fell an additional 11–15 m. Because the lake level is chiefly controlled by evaporation and river input, we infer that more water was supplied to Lake Baikal during warm stages. [Copyright &y& Elsevier]

The article focuses on a study to investigate the petrogeochemical and isotope specifics of terrigenous rocks found in close paragenetic association with island arc magmatic complexes from the example of Neoproterozoic complexes of the Predivinsk Terrane of the Yenisei Ridge in Russia. The Western Block has metaplagiorhyolite–basalt and metaandesibasalt–andesite–dacite associations metamorphosed under the presence of the epidote amphibolite facies.

This study presents new compositional and S-Os isotope data for primary Ru-Os sulfides within a platinum-group mineral (PGM) assemblage from placer deposits associated with the Verkh-Neivinsk massif, which is part of the mantle ophiolite association of Middle Urals (Russia). The primary nature of Ru-Os sulfides represented by laurite (RuS2)–erlichmanite (OsS2) series is supported by occurrence of euhedral inclusions of high-Mg olivine (Fo92–94) that fall within the compositional range of mantle (primitive) olivine (Fo 88–93). The sulfur isotope signatures of Ru-Os sulfides reveal a range of δ34S values from 0.3 to 3.3‰, with a mean of 2.05‰ and a standard deviation of 0.86‰ (n = 18), implying that the sulfur derived from a subchondritic source. A range of sub-chondritic initial 187Os/188Os values defined for Ru-Os sulfides (0.1173–0.1278) are clearly indicative of derivation from a sub-chondritic source. Re-depletion (TRD) ages of the Verkh-Neivinsk Ru-Os sulfides are consistent with prolonged melt-extraction processes and likely multi-stage evolution of highly siderophile elements (HSE) within the upper mantle. A single radiogenic 187Os/188Os value of 0.13459 ± 0.00002 determined in the erlichmanite is indicative of a supra-chondritic source of HSE. This feature can be interpreted as evidence of a radiogenic crustal component associated with a subduction event or as an indication of an enriched mantle source. The mineralogical and Os-isotope data point to a high-temperature origin of the studied PGM and two contrasting sources for HSE in Ru-Os sulfides of the Verkh-Neivinsk massif. [ABSTRACT FROM AUTHOR]

The article presents a study on the sulfates and sulfide in nitrogen hot springs of the Bauntov group of the Baikal Rift Zone (BRZ) in the Vitim River Basin in Russia. It says that physicochemical characteristics of nitrogen hot springs were examined using analytical techniques and precipitates for the assessment of isotopes were obtained by deposition with cadmium acetate, sulfate sulfur, and barium chloride. The results suggest that sulfide sulfur in the hot springs is depleted in heavy isotopes compared with that of sulfates and the chemical oxidation of sulfide sulfur under reduced environments at high Eh values is inconceivable. It adds that the influence of sulfate reduction in the improvement of sulfate sulfur in a heavy isotope is apparent.

The radioisotope compositions, structure, and behavior of “hot” particles under the natural conditions of the Yenisei River in the nearby influence zone of Krasnoyarsk mining and chemical combine were examined in this study. By the composition of gamma-radiating isotopes, all particles are divided into three groups: mono-isotopic, bi-isotopic and poly-isotopic. Mono-isotopic “hot” particles, containing only 60Co were discovered for the first time. Transuranium elements (241Am and 243Cm) were revealed in poly-isotopic particles. Investigation of poly-isotopic particles by means of a scan electron microscope showed that the presence of UO2 together with the lack of activation of 152Eu testifies to the reactor origin of this particle. Experiments showed that in natural conditions “hot” particles under the influence of filtrating water and moisture of pore solutions are gradually dissolved and radionuclides are repeatedly drawn into migration. [ABSTRACT FROM AUTHOR]

The occurrence of hydrocarbon gases (HCG) in unusually high concentrations for magmatic complexes, in the Lovozero and some other alkaline massifs, is of both geochemical and practical interest. The nature of these gases, despite the long history of research, remains the subject of debate. As an approach to solving this problem, we studied the coupled distribution of occluded HCG and the recognized tracers of various geological processes, such as helium and argon isotopes. The extraction of the gas components trapped in fluid micro-inclusions was carried out by the mechanical crushing of rock and mineral samples. A positive correlation was found between the 3He/4He and CH4/C2H6 ratios, whereas a negative correlation of the latter was found with the 36Ar concentration, which in turn was directly related, in varying degrees, to the content of HCG and most strongly with pentanes. Conjugacy of the processes of the heavier gaseous hydrocarbons, a loss of the deep component of the fluid phase and dilution of it with the atmogenic component was established. In the absence of a correlation between CH4 and 3He, the value of the CH4/3He ratio in the Lovozero gas substantially exceeded the estimates of it in gases of a mantle origin, and mainly corresponded to the crustal values. However, in some samples, a small fraction of mantle methane was allowed. The peculiarities of the relationships between hydrocarbon gases and the isotopes of noble gases indicate a sequential process of abiogenic generation and transformation of HCG at the magmatic and post-magmatic stages during the formation of the Lovozero massif. The obtained results confirm the usefulness of this approach in solving the origin of reduced gases in alkaline igneous systems. [ABSTRACT FROM AUTHOR]

We measured δ13C of CO2, CH4, and acetate-methyl in profundal sediment of eutrophic Lake Dagow by incubation experiments in the presence and absence of methanogenic inhibitors chloroform, bromoethane sulfonate (BES), and methyl fluoride, which have different specificities. Methyl fluoride predominantly inhibits acetoclastic methanogenesis and affects hydrogenotrophic methanogenesis relatively little. Optimization of methyl fluoride concentrations resulted in complete inhibition of acetoclastic methanogenesis. Methane was then exclusively produced by hydrogenotrophic methanogenesis and thus allowed determination of the fractionation factors specific for this methanogenic pathway. Acetate, which was then no longer consumed, accumulated and allowed determination of the isotopic signatures of the fermentatively produced acetate. BES and chloroform also inhibited CH4 production and resulted in accumulation of acetate. The fractionation factor for hydrogenotrophic methanogenesis exhibited variability, e.g., it changed with sediment depth. The δ13C of the methyl group of the accumulated acetate was similar to the δ13C of sedimentary organic carbon, while that of the carboxyl group was by about 12% higher. However, the δ13C of the acetate was by about 5% lower in samples with uninhibited compared with inhibited acetoclastic methanogenesis, indicating unusual isotopic fractionation. The isotope data were used for calculation of the relative contribution of hydrogenotrophic vs. acetoclastic methanogenesis to total CH4 production. Contribution of hydrogenotrophic methanogenesis increased with sediment depth from about 35% to 60%, indicating that organic matter was only partially oxidized in deeper sediment layers. [ABSTRACT FROM AUTHOR]

Reports on the Joint Institute for Nuclear Research in Russia and Lawrence Livermore National Laboratory researchers' production of an isotope of element 106 that emits an alpha particle with a low energy within a decay time between 10 and 30 seconds. Stability of the isotope in comparison with the nuclides; Theory of the rock of stability; Establishment of genetic links of decay chains.

Long-range transport of air pollution from continental Asia is currently an important issue concerning the Japanese environment, especially in regions susceptible to acidification due to low buffering capacity, such as Murakami, Niigata prefecture, located on the west coast of central Japan. Evidence for long-range transport was obtained through lead and lead isotopic analysis of 84 archived precipitation filters, showing seasonal changes in lead deposition from May 1999 to May 2002. Lead deposition was highest in winter and spring (November through May) each year and lowest in summer. Computed 72-h back trajectories showed that in winter air masses were predominantly transported from the northwest, passing over northern China and eastern Russia, whilst in summer air masses predominantly originated from the southeast passing over Japan. Lead isotopic analysis showed higher (208)Pb/(206)Pb during winter, indicating that lead originated from a different source. A plot of (207)Pb/(206)Pb vs. (208)Pb/(206)Pb identified a thorogenic component, which is excess (208)Pb compared to a standard lead growth curve, indicative of certain lead ores and coals in continental Asia. The data provided evidence of long-range transport of lead from continental Asia to Japan. Bark pockets included within the trunks of two Japanese cedar trees harvested near Murakami, dating between 1972 and 1982, exhibited lead isotope ratios indicative of Japanese-sourced lead. In contrast, current (2003) bark showed thorogenic ratios, consistent with a relative decline in Japanese-sourced and increase in continental-sourced lead.

Transplants of the lichen Hypogymnia physodes, which is relatively tolerant to SO2 and heavy metals, were deployed for 3 months over a 60 km long SW-NE transect centered on a highly polluting Cu smelter and its adjoining town of Karabash, southern Urals, Russia. The abundance of 206Pb, 207Pb, 208Pb, and 204Pb were determined by MC-ICP-MS. The measurement of 204Pb revealed critical features, which would otherwise remain concealed: (i) The precise isotope ratios referenced to 204Pb allowed several different sources to be resolved even within the small area covered: (a) the obvious pollutant source of the Karabash Cu smelter; (b) two dispersed sources, likely to include soil with lower and different contributions of thorogenic and uranogenic lead; and (c) one anthropogenic source with higher contribution of 235U derived Pb. (ii) In part of the transect, the Pb isotope composition changed while the Pb concentrations remained the same. This indicates that the Pb content of the transplantation material from the background site was largely replaced and that the transplants provide a transient record reflecting a continuous accumulation and loss of environmental Pb, probably mainly in the form of extracellular particles. Overall, the method of lichen transplantation coupled with Pb isotope ratio determinations proved effective in assessing the usefulness of lichens in biomonitoring and in resolving different sources of atmospheric deposition.

A uranium-lead zircon age for a volcanic ash interstratified with fossil-bearing, shallow marine siliciclastic rocks in the Zimnie Gory section of the White Sea region indicates that a diverse assemblage of body and trace fossils occurred before 555.3 +/- 0.3 million years ago. This age is a minimum for the oldest well-documented triploblastic bilaterian Kimberella. It also makes co-occurring trace fossils the oldest that are reliably dated. This determination of age implies that there is no simple relation between Ediacaran diversity and the carbon isotopic composition of Neoproterozoic seawater.