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Kimberlites are deep and relatively rare mantle‐derived igneous rocks, which provide key insights into the lithospheric mantle composition beneath continents (i.e., from the entrained mantle materials) at the time of magma emplacement. In addition, the temporal distribution of kimberlites throughout Earth's history may reveal secular changes in global geodynamics. However, alteration and abundant exotic material (i.e., xenoliths and xenocrysts) of different ages, both typical of kimberlites, often hinder reliable dating of these rocks. In this study, we investigated zircon xenocrysts and their replacement by desilicification reaction rims (DSRs), which consist mainly of baddeleyite, in the metamorphosed Kimozero kimberlites from the Karelian Craton, Russia. Similar DSRs have been identified previously on mantle‐derived zircons in numerous kimberlites, but the precise timing and location of formation of these rims remain unclear. U–Pb isotope dating of mantle zircon xenocrysts in the Kimozero kimberlites indicates that these rocks were emplaced at ca. 1.97 Ga. DSRs with similar textures and baddeleyite chemistry occur on both the 1.97 Ga mantle and 2.70–2.38 Ga crustal zircon xenocrysts in these kimberlites. Pb–Pb isotope dating of the DSRs yields the same age (i.e., ca. 1.97 Ga) as the mantle zircons. The data constrain the formation of DSRs to crustal levels and, more importantly, indicate that these rims record the timing of kimberlite emplacement. Therefore, we suggest that such baddeleyite reaction rims are a new and promising material for kimberlite geochronology. Plain Language Summary: Kimberlites are magmatic rocks produced by magma that ascended from mantle depths. It is important to obtain accurate kimberlite ages mainly because: (a) mantle rocks and minerals, carried by these magmas, allow assessment of the composition of the lithospheric mantle beneath continents at the time of kimberlite emplacement; and (b) the worldwide distribution of kimberlite ages may record secular changes in global geodynamics. However, kimberlites are readily altered and commonly contain exotic material of different ages and origins, which both hinder reliable kimberlite dating. Here, we investigated xenocrystic zircons and their reaction rims, which consist mainly of baddeleyite, in the strongly altered Kimozero kimberlites. Similar rims have been identified on mantle‐derived zircons in numerous kimberlites, but the timing and location of rim formation is poorly constrained. We found that the rims have replaced zircon xenocrysts of different ages and with both mantle and crustal origins, implying the rims formed at crustal levels. The results of Pb–Pb dating for these rims compared with those obtained from zircon U–Pb dating indicate that the rims record the timing of Kimozero kimberlite emplacement at ca. 1.97 Ga. Therefore, such baddeleyite rims are suggested as a promising material for obtaining reliable kimberlite ages. Key Points: Desilicification (i.e., baddeleyite) rims replace kimberlite‐hosted zircon xenocrysts of mantle and crustal originsThese rims represent a promising material for kimberlite geochronology, as they form at the time of kimberlite emplacementThe Kimozero kimberlites intruded the Karelian Craton at ca. 1.97 Ga [ABSTRACT FROM AUTHOR]

High-grade epithermal Au–Ag veins of the Vodorazdelnaya district in far eastern Russia are hosted by Early Cretaceous volcanic rocks of the Tytylveem belt. The largest deposit is Zone 37, a 1-km long, northeast-striking vein that is up to 35-m wide, containing at least 32 t Au. The main shoot consists of crustiform—colloform banded quartz-chalcedony-adularia-sulfide veins, of low-sulfidation style. The vein is cut by late-mineral rhyolite sills and dikes. Zone 37 vein is dated at 117 ± 2 Ma, overlapping within error with the cross-cutting rhyolites (121–119 Ma) and with intrusions of the nearby Ilirney granitic pluton (119–117 Ma). The volcanic host rocks are dated at 121–115 Ma. At September Northeast, 15 km west-northwest of Zone 37, mineralisation consists of veins up to 4 m wide, with crustiform banded quartz ± chalcedony ± adularia ± chlorite, and Zn-Pb-Cu sulfides, of intermediate sulfidation style, in a 1-km-long, north-northeast striking trend. High grades are associated with gold dendrites in fine-grained quartz bands and with minor late-stage tellurides. The veins were disrupted by intrusion of rhyolite dikes and associated phreatic breccias. Some breccias host mineralisation as vein clasts and minor matrix sulfides. The Tytylveem belt is preserved below a regional unconformity that forms the base to the overlying Late Cretaceous (106–77 Ma) Okhotsk-Chukotka Volcanic Belt (OCVB). Intrusive rocks attributed to OCVB magmatism were emplaced at about 96 Ma and are associated with overprinting hydrothermal alteration, sub-economic veins and thermal resetting of some vein adularia ages at Zone 37, to 91–97 Ma. [ABSTRACT FROM AUTHOR]

Granites, especially those that were decompressed as a result of processes of secondary transformations and tectonic movements, hold the greatest potential in the search for oil-bearing rocks in basements of sedimentary basins. Owing to the chemical dating of monazites from collision granites of the East Shebur area, the isochrone age of 274.5 ± 21 Ma was obtained. Zircons (SHRIMP-II) yield a concordant age of 277.5 ± 2 Ma (MSWD = 0.77). The Rb-Sr isochrone age of granites (247.4 ± 9.1 Ma) coincides with the emplacement time of the West Siberian rift system. This age records the process of intruding East Shebur granites into the upper crust level during riftogenesis and the extension of the study area. The younger age datings (231 Ma, 60 Ma (U-Pb); 220 Ma (K-Ar)) record the stages of tectonomagmatic activation, recorded in the basement of the Western Siberia oil-bearing areas. [ABSTRACT FROM AUTHOR]

Abstract: The paper summarizes the results of recent studies of Late Pleistocene postglacial geological events which occurred in the flatlands of northern Russia stretching from the Timan Ridge to the Laptev Sea coast. The available sedimentary record includes thawed and perennially frozen subaerial sediments and in places lacustrine and fluvial formations. Hundreds of geochronometric measurements by radiocarbon and luminescence techniques place this record within the time span of 50–11 ka BP which confirms an Early–Mid-Weichselian age of the underlying glacial complex first established by the QUEEN programme. The spectrum of proxies includes sedimentary facies, pollen data, plant macrofossils, oxygen isotope values, megafauna remains, insect assemblages, traces of DNA, paleosols and permafrost properties. Together they indicate a continental, progressively deteriorating climate with very cold winters and warmer than present summers through the second half of the Late Pleistocene. Minor climatic fluctuations are largely due to slightly changing humidity during MIS 3. These changes are more pronounced in periglacial European Russia in the vicinity of the Barents–Kara ice sheet where the Mid-Weichselian biotic maximum contrasts with conditions in the Late Weichselian polar desert. In Siberia, the periglacial environments were more stable and beneficial for biota inspite of the increased continentality. The recent data accumulated by various researchers are incompatible with the conventional correlation of the Karginsky interglacial strata of Siberia with MIS 3 or any part of the European Pleniglacial. [Copyright &y& Elsevier]

The article estimates the age of the rocks of Solzan granitoid massif of the Khamar-Daban Province in Baikal, Russia using uranium-lead dating method. It analyzes the composition of the massif in the eastern which include granodiorite-gneiss and granite with amphibole, biotite, or garnet in dependence on the composition of host gneiss. It examines the accessory zircons that were extracted from samples representing biotite and garnet-biotite biotite leucogranites of layered bodies from the eastern part of the massif. It cites the uranium-lead dating of zircons which showed that magmatic zircons from granite melts in the Solzan massif started to crystallize 516-515 million years ago.

The article discusses the age of extrusive rocks found in Kamchatka Peninsula, Russia, and highlights the application of laser ablationin dating of young zircons. It informs that the application of tephra chronology and radiocarbon dating resulted in the study of the chronology of volcanism in the Holocene period. It also informs that pan sampling for zircons and their geochronologic studying can be used in solving various problems.

The article focuses on the study regarding the hydrothermal systems in the mid-oceanic ridges (MAR) which was participated by various countries including Great Britain, France, and Russia. It states that the study used geophysical and geological methods in the segment of MAR following the discovery of the hydrothermal ore fields called Zenith-Victoria and Petersburg. It says that the ore mineral composition was able to identify with use of quantitative chemical analysis. Furthermore, it mentions the used of micropaleontological method to determine the age of a certain metalliferous sediments. Moreover, it mentions the three ore bodies which constitutes the ore field.

The article offers information on the determination of the age of granitoid plutons in Chauna zone of Verkhoyansk mountains in Chukotka, Russia. It mentions that granitoids in the said zone are composed of batholiths with an area of up to 2000 km2. It cites a dating of zircons from granitoids of two plutons Velitkenai and Moltykan in North Chukotka done though the process of elongation of zircons. It states the age of the samples estimated at 107.0 ± 1.0 Ma for Moltykan pluton and 105.3 ± 1.2 Ma for Velitkenai pluton.

The Phanerozoic tectonic evolution of the Chuya-Kurai zone was studied by means of zircon U/Pb-dating, apatite fission track (AFT) and apatite (U-Th)/He (AHe) thermochronology performed on basement rocks. Our results suggest that multiple magmatic episodes during the Paleozoic, related to the accretion-collision tectonics in Central Asia, affected our study area. Mesozoic and Cenozoic basement cooling events are interpreted as periods of tectonic reactivation. A new tectonic model for Late Cenozoic evolution of the Chuya-Kurai zone is proposed. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses uranium (U)-lead (Pb) geochronological dating of Paleozoic era granitoide rock formation of the Kiviliyskii complex in the Bureya Terrane in Russia. It says that porphyroblastic granites and rare quartz diorites from the Kiviliyskii massif were used as samples, in which accessory zircon crystals were selected and were subjected to multiple removal of surface contamination with ethanol, acetone, and nitric acid (HNO3). It says that Krogh's modified procedure was used for the chemical decomposition of zircon and U and Pb separation and isotope analyses were performed with the use of the MAT 261 multicollector mass spectrometer from Finnigan Corp. Results show that the granitoides in the site have an early Paleozoic era age.

The article presents a study on the zircon content of pyroxene from the Ishkul site southern termination of the central alkaline complex at the Ilmeny Mountains in the Ural Mountains in Russia, near Selyankino. It states that the sensitive high-resolution ion microphobe (SHRIMP) -II dating was used to determine the age of the zircons which has chemical composition including silicon oxide, titanium oxide, and aluminum oxide. It mentions that the sample C of zircon crystals is a miaskitic type indicating a hybrid, and the samples are formed near the mantle formation based on its composition. It adds the gneiss where the zircons are found has been preserved to determine their origin.

The article discusses the Denisovans, which were a group of archaic humans that researchers hypothesize lived in the same area as both modern humans and Neandertals and whose range may have stretched into east Asia. Topics include an overview of the discovery of several fossils and tools in Denisova Cave in the Altai Mountains of Siberia, by anthropologist Bence Viola, and the results from a DNA analysis of the fossils, which revealed that the fossils were from both Neandertals and Denisovans. Also discussed is research by paleogeneticist Svante Pääbo and archaeologist Anatoly Derevianko mapping the trail of ancient humans, including the use of advanced methods in toolmaking and whether the Denisovans, Neandertals, and modern humans may occupied the Altai Mountains simultaneously. INSET: A Denisovan Legacy in the Immune System?.

This paper discusses the results of U-Pb isotopic dating of zircons from hornblendites that cut dunites of the East Khabarny dunite-clinopyroxenite-websterite-gabbro complex in the South Urals. This complex is included into the structure of the large Khabarny mafic-ultramafic allochthon, and the set of rocks and their petrogeochemical peculiarities allow this complex to be compared with the Ural-Alaskan-type complexes. Zircons from hornblendites have been dated on a SHRIMP-II ion microprobe and by the classical thermo-ionization mass spectrometric method by five fractions. The obtained results are comparable between each other within the analysis deviation interval and show that hornblendites were formed in the Early Devonian (408-402 Ma). This age is the upper geochronological limit in estimation of the time when dunites of the East Khabarny complex were formed. The synchronity of intrusive hornblendite manifestation in most of the Urals in the Early Devonian is discussed. The probable Early Devonian stage, in addition to the found Vendian and Ordovician-Silurian ones when dunite-clinopyroxenite-gabbro complexes formed in the Urals, is suggested. [ABSTRACT FROM AUTHOR]

U-Pb dating of zircons (SHRIMP-II) has been performed for the first time for granites, granodiorites, and synplutonic granodiorite and melanodiorite bodies of the Shartash and Shabry massifs in the Middle Urals. The time of the formation of the massifs is 300-306 Ma, which is 25 Ma younger than the previous estimates. The age data obtained are in line with the time of the formation of the adamellite-granite series of the Verkhisetsk Batholite (the master sample of tonalite-granodiorite-granite magmatism in the Middle Urals), the series of which is petrochemically close to the rocks of the massifs. [ABSTRACT FROM AUTHOR]

The article presents a study to determine the geologic age of early caledonides formation in Olkhon Island, Russia. It says that the region possesses unique geological characteristics where different levels of the Earth's crust are exposed and separated by three main lithoplates created by collisional-shear zone deformations. The lithoplates are the Chernorud zone, composed of granulite facies metamorphism, the Anga-Sakhyurty zone, composed of amphibolite facies metamorphism, and the Anga zone, composed of epidote-amphibolite metamorphism. It says the study used Uranium-Lead (U-Pb) isotope dating of zircons performed on the SHRIMP-II ion microprobe and confirmed through the Triton X-100 mass spectrometer. The results show that Birkhin gabbroic massif age is at 500 million years (Ma).

The article presents a study that investigates the age of granitoids and the ancient basement of the Western Siberian Platform. Data were gathered in an interfluve of the Elogui and Vakh rivers in the east of Western Siberian Plate and granitoids were in the alkaline granites field. Potassium-argon dating (K-Ar) of all rocks showed that Tyn'yarskii rhyolite'granite massif's age was probably Early Permian. Extraction and analysis of zircons from Samples Tyn-101/2590 meters (m) and Tyn-100/2204 m were performed. Results show that dipyramidal and molten resorbed zircon crystals in the samples had an age range of 270-280 mya (Ma). The study concludes that the basement may be ancient granite-metamorphic.

Abstract: A geochronometric database, comprising 121 optically stimulated luminescence and 59 radiocarbon dates plus U/Th date on peat from 24 key sections in northern West Siberia is presented and discussed. These data have been obtained during Russian–Norwegian joint research for the past 15 years and are augmented by reports on radiocarbon dated mammoth carcasses in West Siberia. Together they provide the basis for revising the regional stratigraphic scheme and for correlation to the European Quaternary chronostratigraphy and marine oxygen isotope record. The geochronologic correlation of sedimentary formations across West Siberia involves classical stratotypes of fluvial, shallow limnic and temperate marine sediments of the Karginsky Horizon, ca 130ka, which was previously attributed to MIS 3. The older Kazantsevo marine formation is thus assigned a Middle Pleistocene age. The uppermost glacial sedimentary complex containing glacial ice was deposited by shelf-based ice sheets between ca 100 and 60kaBP. The postglacial Pleistocene sediments are mostly ice-bound loess-like deposits and sink-hole silts containing numerous mammoth carcasses that are radiocarbon dated to between ca 42 and 25kaBP. There are no traces of glacial activity on the Siberian plains during MIS 2, a period for which palaeoclimatic proxies suggest a cold and dry environment. This synthesis indicates that the prior usage of the Siberian correlation horizons of Kazantsevo and Karginsky as equivalents of the Eemian and Middle Pleniglacial is stratigraphically invalid. [ABSTRACT FROM AUTHOR]

The article focuses on a study that explores the hydrothermal mineralization and sources of metals of the Nezhdaninsko gold deposits in Yakutia, Russia. It highlights the application of a nontraditional approach based on hydrothermal quartz as a rubidium-strontium (Rb-Sr) geochronometer to determine the dating of vein mineralization of such deposits. Moreover, a method of isotopic dilution on a seven-collector mass-spectrometer Micromass Sector 54 was used in all of the measurements of Sr isotopic composition and Rb and Sr concentrations.

Abstract: The sequences of various facies of Upper Khazarian sediments on the right bank of the Lower Volga south of Volgograd were dated using four independent dating techniques: Thorium–Uranium, thermoluminescence, electron spin resonance, and paleomagnetism. A reliable correlation of the Late Khazarian Basin with MIS 5 was obtained: the transgressive phase corresponds to MIS 5.5, and the regressive to MIS 5.4–5.1. Quantitative estimations of paleotemperature and paleosalinity for the Caspian Late Pleistocene basins show the highest salinity values correspond to the transgression maxima. The highest (summer) paleotemperatures were also recorded in the maximum phases of the Late Khazarian and Early Khvalynian transgressions. The isotopic composition of water oxygen in the Late Khazarian, Early and Late Khvalynian basins was estimated. [Copyright &y& Elsevier]

The article presents a study on the Sm-Nd and Rb-Sr ages of granitoids, gabbroids and titanomagnite ores from the layered gabbro intrusions belonged to Kusa-Kopan Complex in Urals, Russia. It discusses the geological structure and mineral composition of gabbroids, granitoids, and ores deposits which were determined by the PT parameters and fluid changes of formations. It says that garbronorites of the ore zone were sampled to determine the Sm-Nd age of grabbroids from the Kusa Massif characterized by a transition to dominant hornblende gabbro. Precision multichemical solid-phase (TIMS) analyzer Finnigan MAT 262 which measures the isotopic composition of resulting mixture and mass-spectrometry method of isotopic dilution (ID) were employed for isotopic dating.

The article discusses the method of isotope-geochronological timing of rock metamorphism at the boundary zone of Aldan Shield and the Dzhugdzhuro-Stanovoi Folded Area in the area of Nagornyi Village and Kholodnikan Pass in Russia. The method indicated an overthrust-sheet structure that developed in the zone and a tectonic plate that moderately points to the south. Further observations showed that the metamorphic rocks are deformed linearly or folded isoclinally in the latitudal direction parallel to the whole junction zone.

The article discusses the study on the mineralogy, geochemistry and age peculiarities of zircon distribution on gneissose leucocratic miaskites of the Ilmenogorsk massif deposit at the southern region of Ural Mountains in Russia. Researchers conducted recrystallization of the zircon samples from amphibole miaskites that yielded formation of emulsion structures, crushing and corrosion, and new growth. From the authors' findings, ages of miaskite crystallization, 434 plus 15 minus 10 million years (Ma), and metamorphism, 239 plus 40 minus 45 Ma, were determined by standard uranium-lead (U-Pb) dating method.

The article offers information on the results of the dating of alkaline granitoids of the Ulug-Tanzek Massif deposit in Tuva, Russia through uranium-lead (U-Pb) method for zircon and Argon-Argon (Ar-Ar) method. A sample from polylithionite-bearing ribeckite granite was studied for Ar-Ar geochronological investigations, in which, results revealed that approximately 85% of Ar that has clearly formed reflected three-step plateau with an age of 296 plus-minus two million years (Ma). In U-Pb dating, a sample of muscovite quartz-albite-microline granite with a netlike texture was used, in which, the determined age of 301 plus-minus three Ma, is similar within the error limits of the age estimation for the first sample using Ar-Ar method.

Here we present a series of six maps illustrating the distribution of end moraines in Far NE Russia. The maps are the first to systematically document the distribution of moraines across this region from the Verkhoyansk Mountains at the westernmost limit of our study area to the Chukchi Peninsula in the NE and to Kamchatka in the south, covering almost 4 million km2. Moraines were identified and mapped from analysis of satellite images and digital elevation model data. A total of 2173 moraines are identified, and we highlight some 197 more speculative features (perhaps moraines) that require further investigation. The distribution of moraines indicates that much of the region, now largely ice-free, was formerly occupied by glaciers centred upon the region's uplands and that glacier outlets were typically < 200 km in length. The maps demonstrate the usefulness of remote sensing to derive an improved understanding of the glacial history of this vast and isolated region, and we present them to stimulate further work and act as a systematic framework for targeted geochronometric dating. [ABSTRACT FROM AUTHOR]

Abstract: We present a new, reliably dated Mesoproterozoic paleopole for Siberia, based on a combined geochronological and paleomagnetic study of mafic rocks within the Mesoproterozoic Sololi Group of the Olenek Uplift in northern Siberia. Ion microprobe (SHRIMP) U–Pb analysis yields crystallisation ages of 2036±11Ma for zircon from a basement granite and 1473±24Ma for baddeleyite from a large dolerite sill within the Kyutingde Formation. The baddeleyite result indicates that the lower Sololi Group is significantly older than was suggested by previous K–Ar results. Paleomagnetic analysis of the dolerite sill and related mafic intrusive rocks yields a paleopole at 33.6°N, 253.1°E, A 95 =10.4°. A positive baked-contact test between the Kyutingde sill and sedimentary country rocks shows that the magnetisation is primary. Comparison of this paleopole with coeval results for Laurentia provides a revised reconstruction between Siberia and Laurentia, and implies that these two continents were parts of a single Mesoproterozoic supercontinent since at least 1473Ma. We argue that Siberia, Laurentia, and Baltica belonged to the same supercontinent between 1473Ma and mid-Neoproterozoic time. [Copyright &y& Elsevier]

Abstract: Economic Ag–Sb deposits are located within four large ore districts of Central Asia: SE Altai–NW Mongolia, SE Pamir (Tajikistan), Talas (Kyrgyzstan) and Verkhoyansk province (Yakutia), where Ag–Sb ores are spatially associated with tin mineralization. The geology, mineral composition and geochemistry of the Ag–Sb deposits, age of mineralization, distribution and genesis are presented in this paper. Results of new studies show that Ag–Sb ores commonly occur within Sn ore provinces and can be divided into three groups according to their relationships with tin mineralization. Ag–Sb deposits of the first group are spatially isolated from Sn–W ore fields and from metamorphic haloes of Sn-bearing granitoids (pre-granitic deposits of the Mangazeisky ore cluster in Yakutia and deposits of the Asgat-Ozernoe ore zone in the SE Altai–NW Mongolia). A 240±3.5 Ma 39Ar/40Ar age of Ag–Sb mineralization was determined for the Asgat deposit (SE Altai–NW Mongolia), which correlates well with the 243±3.7 Ma 39Ar/40Ar age of alkaline mafic intrusions (lamprophyre dike). The Ag–Sb ore appears to be younger than Sn–W mineralization (352±6.0 Ma) related with granite of the Yustid complex (355.7±8.6 Ma). The second group comprises granite-hosted Ag–Sb deposits of the Bazardara ore cluster (SE Pamir) of Paleogene age (44±1.5 Ma) located within a tin ore cluster, but separated in time from the Cretaceous Sn mineralization (98.5±1 Ma, Ar–Ar). Ag–Sb ore veins of the third group are located within tin ore clusters and are nearly coeval with tin mineralization (post-granitic Ag rich ore of the Mangazeiskoe, Prognoz and Menkechenskoe deposits, Verkhoyansk province). A close spatial and temporal relationship of Ag–Sb deposits with Sb–Hg mineralization and alkaline mafic magmatism is observed. Helium isotope systematics from the ore-forming fluids of Ag–Sb Akjilga deposit (Pamir) confirm the role of mantle helium in the ore-forming process. Another important indicator of a mantle source in these Ag–Sb deposits is the Hg content in the ores; Hg being a typical element of mantle origin. Isotopic (3He/4He, 87Sr/86Sr, Pb, S) and geochronological data demonstrate that Ag–Sb deposits are polygenetic in sources of ore matter and relate to the mantle-crustal ore-magmatic systems. [Copyright &y& Elsevier]

Novaya Zemlya was covered by the eastern part of the Barents–Kara ice sheet during the glacial maximum of marine isotope stage 2 (MIS 2). We obtained 14C ages on 37 samples of mollusc shells from various sites on the islands. Most samples yielded ages in the range of 48–26 14C Ky. Such old samples are sensitive to contamination by young 14C, and therefore their reliability was assessed using replicate analyses and amino acid geochronology. The extent of aspartic acid racemization (Asp D/L) indicates that many of the 14C ages are correct, whereas some are minimum ages only. The results indicate that a substantial part of Novaya Zemlya was ice-free about 35–27 14C Kya, and probably even earlier. Corresponding shorelines up to >140 m a.s.l. indicate a large Barents–Kara ice sheet during early MIS 3. These results are consistent with findings from Svalbard and northern Russia: in both places a large MIS 4/3 Barents–Kara ice sheet is postulated to have retreated about 50 Kya, followed by an ice-free interstadial that lasted until up to ca. 25 Kya. The duration of the MIS 2 glaciation in Novaya Zemlya was calculated by applying the D/L values to a kinetic equation for Asp racemization. This indicates that the islands were ice covered for less than 3000 years if the basal temperature was 0oC, and for less than 10 000 years if it was −5oC. [ABSTRACT FROM AUTHOR]

The article discusses the study done to examine the age of Udachnaya-East Kimberlite by using Uranium-lead (U/Pb) dating of perovskites and zircons and Arsenic dating of xenoliths and xenocrysts. Topics discussed include difficulty in the determination of the age through isotopic methods, low Uranium content in the mantle zircons, and using isochrone method for the estimation of the kimberlite age.

Simple Summary: Fossil click beetles from the family Elateridae are frequent in Mesozoic deposits, especially in Russia and China. In order to understand their relationship to extant species, we need to search for evolutionary important characters that unite these dinosaur-era beetles with extant forms. We show that about one third of the identifiable click-beetles described from Mesozoic Chinese deposits are in fact members of other related families. Our results strengthen the view that these beetle groups are significantly older than often assumed, being present in the Early Jurassic. This is an important result as it indicates that molecular studies based on modern species do not replace paleontology—both are needed, even in the future. Recent molecular studies have suggested that the clicking beetle families Elateridae, Eucnemidae, Throscidae, and Cerophytidae evolved in the Jurassic and diversified in the Cretaceous. These studies paid little attention to fossils, using them only as dating tools. The identification of Elateridae fossils is challenging, as external synapomorphies are not known for this family. Elateridae can be identified only as something not belonging to the other related families, all of which have diagnostic synapomorphies. Most subfamilies and tribes of Elateridae do possess definite diagnostic characters, however, making their identification feasible. We checked the 28 Elateridae described from Chinese Mesozoic deposits. Twelve were Elateridae, seven were Eucnemidae, and one was a Throscidae. Three species could be Eucnemidae, but showed aberrant characters. Five species could not be placed and may not belong to Elateroidea at all. On the basis of these results we suggest that all previously described Elateridae fossils should be re-checked. They should be searched for synapomorphies defining Eucnemidae, Throscidae, and Cerophytidae. If such characters are not present, a click beetle type of fossil can be placed in Elateroidae incertae sedis. The Mesozoic Chinese Elateridae fossils all belong to clades that do not exist today, whereas the Mesozoic Eucnemidae subfamilies are extant ones. This may be the source of the disagreement between Elateridae fossil age and datings based on molecular studies. One new combination was made: Desmatus ponomarenkoi (Chang, Kiretjshuk & Ren, 2009) NEW COMBINATION (= Paradesmatus ponomarenkoi Chang, Kirejtshuk & Ren, 2009). [ABSTRACT FROM AUTHOR]

The article focuses on obtaining the ages of the mammoth remains in the submoraine sediments in Kola Peninsula and Karelia. It says that mammoth remains were also seen in marine sediments of southern Kola Peninsula in Varzuga River under Valdaian moraine with sublittoral Arcto-Boreal marine molluscan species. It tells that ages of the remains were determined by different paleontologist as ranging from middle Valdaian to the Mikulinian. It mentions that palynological data on the lower part of the Ponoi clays in the locality of the animal fossils open assumption that the mammoth dwelt in the southern Kola Peninsula during the development phase of thin pine and birch forests with soil widely covered with green mosses.

The article discusses significance of the uranium-lead (U-Pb) geochronological study of bastnaesite from the Karasug complex deposit at the Central Tuva in Russia. Bastnaesite is a typomorphic mineral that is usually found in siderite carbonatites. During the analytical method of the study, modified Krogh technique was employed to decompose bastnaesite and chemically separate Pb and U. According to the author, U-Pb dating of bastnaesite was taken through a supergene altered siderite carbonatite with hematite. In the process, the authors noted that there is a possibility of applying bastnaesite as a tool for U-Pb geochronological dating of endogenous ore processes.