New constraints on local geology, geochemistry, and geochronology (LA-ICP-MS U-Pb detrital zircon ages) have been obtained for metamorphic clastic rocks assigned previously to the Khargitui Formation, presumably the oldest clastic rocks in the Sarma segment of the Akitkan orogenic belt in the southern Siberian craton. The new data reveal three units of rocks formed at different stages of the Akitkan orogen evolution. Unit 1 includes mainly leucocratic gneisses derived from 2.7-2.5 Ga polymictic sandstones or graywackes. These sediments were deposited upon the basement of the Sarma terrane composed of 2.88 Ga TTG granitoids that became the source of clastic material. Unit 2 consists of quartzite and schists produced by metamorphism of quartz and polymictic sandstones and siltstones. Judging by the ages of detrital zircons from mica-quartz schists, along with the age of metamorphism, the deposition of the sedimentary protoliths lasted from 2.15 to 1.95 Ga. It was maintained by destruction of felsic rocks within the Sarma terrane prior to the collisional event that led to the formation of the Akitkan orogen. Unit 3 likewise includes quartzites and schists but those derived from more mature sediments. The clastic material predominantly originated from 1.88-1.84 Ga rocks of the South Siberian magmatic belt and was deposited in intracontinental basins between 1.00 and 0.72 Ga, after the assembly of the Siberian craton. Synthesis of new and published data for the Sarma rocks allow tracing the Archean-Proterozoic history of the Akitkan orogen, including the pre-and post-orogenic stages of its development.

This article presents and discusses the results obtained by X-ray fluorescence and KAr methods regarding pumice pieces found at two archaeological sites: Ust'-Karenga XVI (9000-8000 cal BP) and Kovrizhka III (similar to 13,000 cal BP) (Vitim River, Transbaikalia, Russia). KAr dating and geochemical characteristics of pumice from the Kovrizhka and Ust'-Karenga sites indicate that they are a product of the eruptions of the Udokan volcanic field, and not the Vitim volcanic field, which are two volcanic regions of Transbaikalia. Ancient people residing at both sites were aware of the same resources within the territories, despite the fact that they lived at different times; this is evidenced by the fact that the archaeological material found in the ritual pit of Ust'-Karenga XVI is similar in terms of cultural remains to the archaeological finds of the Kovrizhka group of sites of the age range from similar to 6700 to 13,000 cal BP. In this work, we assume that ancient people used not only stone resources but also thermal springs of the territory of the Udokan volcanic field. Based on the paleogeographical data of the region, we reconstruct the possible routes used by ancient humans to deliver and/or exchange raw materials necessary for economic purposes. Our new data in combination with previously published data for Transbaikalia and other regions of Siberia suggest that the connection between the ancient populations living in these areas often persisted at distances >1000 km.

В статье рассматриваются результаты исследований нового комплекса культурных остатков на стоянке Коврижка IV (р. Витим, Байкало-Патомское нагорье) в культурном горизонте 3/2. Стояночная структура представляет собой скопление культурных остатков у очага, оконтуренное выкладкой в виде овала (длина 4,7, ширина 3,2 м) из восьми плит, которое определено как остатки жилища. Приводятся сведения о планиграфии комплекса. Очаг находится не в центре, ближе к предполагаемому входу в северо-восточной части. Под одной из плит контурной выкладки выявлено пятно охры. Даются количественная и типологическая характеристики ассамбляжа. Общее количество каменных артефактов — ок. 2,4 тыс. ед. На основе выборочного трасологического исследования к орудиям отнесены четыре отщепа с ретушью и без ретуши (определены как ножи), бифас — клиновидный нуклеус, бифасиальное скребло-нож. В группу орудий входят бифасиальное скребло-нож, 2 фрагмента унифасиальных орудий-скребел, резчик, отщепы с ретушью, всего 12 ед. Найдены три микропластинчатых торцово-клиновидных нуклеуса, один из которых изготовлен из бифаса, а два — из сколов. На основе опыта изучения ранее открытых на Коврижке IV двух жилищ и одного очажного комплекса, а также результатов AMS-датирования (возраст комплекса ок. 18,9-18,6 тыс. л.н.) доказано, что облик рассматриваемой индустрии соответствует ранней фазе позднего верхнего палеолита нижнего Витима. Приводятся данные антракологического исследования, свидетельствующие о тундростепном ландшафте с островами кустарниковой (ивовой) растительности. Сделан вывод о том, что эпизод обитания в жилище был кратковременным. Данный объект вместе с подобными объектами, раскопанными ранее на стоянке Коврижка IV, позволяет составить представление о культуре и деятельности людей в позднем верхнем палеолите в конце Последнего ледникового максимума.

The paper presents the results of estimating firing temperatures of Paleometal Age ceramic sherds discovered in the northern part of the Sakhalin Island by means of experimentation with gradual heating in a muffle furnace. The experimentation included analysis of the ceramic sherds retrieved by the archaeological excavations at the Askasai 7 settlement attributed to the Nabil archaeological culture (7th_ 4th centuries BC). The firing temperature was identified based on changes in the color and texture of the sherds. Presence of plant detritus detected by the petrographic study of thin sections is an evidence of low firing temperature. The experimentation results show that the changes in the texture and color spectrum occurred between 400 C and 500 C, which means that the firing temperature did not exceed this range. According to the obtained data of the petrographic study and the experimentation results, we think that the clay was fired in a bonfire without special structures. Low temperatures of bonfires suggest the use of raw material with low heat release or specific features of the firing season. At the same time thin -walled ceramic pots with tiny pores discovered in the dwellings at Askasai 7 are indicative of a well -established production process. Absence of grog in the temper is typical of expedient technology when, instead of pottery shops, ceramics were produced locally as needed. Presence of grog fragments in one sample and a different firing temperature employed suggest that this vessel was produced elsewhere and/or by a different potter.

We analyze a part of the Paleolithic layer of Afontova Gora IV (Ovrazhnaya) in Krasnoyarsk, evidencing intentional exploitation of outcrops of red sandstone and other local rocks. We describe archaeological finds and faunal remains, identify species important for subsistence. Based on the results of the intrasite spatial analysis, we separate an area of domestic activities centered on an open hearth. Scar-patterns and raw material links were analyzed. The preservation of the cultural context was demonstrated. The area likely functioned within a single activity episode. Types of activity are reconstructed. Primary reduction techniques applied to oval-flat pebbles to get first or second order blades were the same as those used to obtain ready wedge-shaped microcores transported to the site. To test the idea that red rocks were used as sources for mineral pigment, rock samples and archaeological artifacts were examined. In samples from Afontova Gora IV, no minerals that could be used to obtain the red pigment of the “ocher” type were found. Pieces of red rock brought to the site must have been used differently. The 14C-date of the complex with cultural remains is ca 18 ka cal BP.

Приведены результаты комплексных исследований терригенных пород хабаровского аккреционного комплекса Сихотэ-Алиня. Установлено, что в обломках юрских и пермско-триасовых песчаников доминирует слабоокатанный и слабосортированный материал преимущественно из местных источников сноса. Обломочная часть пород представлена в основном кварцем, в меньшем количестве полевыми шпатами и обломками пород. Песчаники характеризуются повышенными содержаниями кремнезема, умеренной глиноземистостью, невысокими концентрациями фемических элементов и кальция, умеренными содержаниями щелочей при значительных вариациях K/Na отношения. Как для юрских, так и для пермско-триасовых пород типичны пониженные в сравнении с PAAS содержания LILE, РЗЭ, в меньшей степени HFSE и отрицательные значения параметра ɛNd(T). Модельный Nd возраст юрских песчаников варьирует от 1.36 до 1.71 млрд лет, пермско-триасовых — от 1.14 до 1.35 млрд лет. Большая часть популяции детритовых цирконов имеет позднепалеозойско-раннемезозойский возраст, примерно 25 % — более древний (до палеопротерозоя). Изученные песчаники являются преимущественно породами первого цикла выветривания (петрогенными), образованными при размыве магматических пород кислого состава. Синтез полученных данных позволяет считать, что главным источником кластического материала для мезозойских осадочных пород служили геологические комплексы северной части Бурея-Ханкайского супертеррейна (Буреинский и Малохинганский блоки), а также, возможно, восточной части Монголо-Охотского пояса. Хабаровский террейн не претерпел значительных перемещений по сдвигам системы Тань Лу и является «автохтонным» блоком в современной структуре Сихотэ-Алиня. The results of comprehensive studies of terrigenous rocks of the Khabarovsk Sikhote-Alin accretionary complex are presented. It is established that the fragments of Jurassic and Permian–Triassic sandstones are dominated by poorly rounded and poorly separated material mainly from local provenance areas. The detrital part of the rocks is mainly represented by quartz, in a smaller amount by feldspar and rock fragments. Sandstones are characterized by high silica content, moderate alumina content, low concentrations of femic elements and calcium, moderate alkali content with significant varia-tions in the K/Na ratio. Both Jurassic and Permian–Triassic rocks are typically characterized by reduced contents of LILLE, REE, to a lesser extent HFSE and negative values of the ɛNd(T) parameter – compared to PAAS. The model Nd age of Jurassic sandstones varies from 1.36 to 1.71 Ga, Permian–Triassic — from 1.14 to 1.35 Ga. Most of the detrital zircon population is of late Paleozoic–early Mesozoic age, approximately 25% are older (pre-Paleoproterozoic). The studied sandstones are mainly rocks of the first cycle of weathering (petrogenic), formed during the erosion of igneous rocks of felsic composition. The synthesis of the obtained data suggests that the main source of the cluster material for the Mesozoic sedimentary rocks was the geological formations of the northern part of the Bureya-Khanka superterrane (Bureya and Malokhingan blocks), as well as, possibly, the east-ern part of the Mongol-Okhotsk belt. The Khabarovsk terrane has not drifted significantly along the Tan Lu stike-slip system and is an “autochthonous” block in the present-day struc-ture of Sikhote-Alin.

The results of comprehensive studies of terrigenous rocks of the Khabarovsk Sikhote-Alin accretionary complex are presented. It is established that the fragments of Jurassic and Permian-Triassic sandstones are dominated by poorly rounded and poorly separated material mainly from local provenance areas. The detrital part of the rocks is mainly represented by quartz, in a smaller amount by feldspar and rock fragments. Sandstones are characterized by high silica content, moderate alumina content, low concentrations of femic elements and calcium, moderate alkali content with significant variations in the K/Na ratio. Both Jurassic and Permian-Triassic rocks are typically characterized by reduced contents of LILE, REE, to a lesser extent HFSE and negative values of the epsilon(Nd)(T) parameter - compared to PAAS. The model Nd age of Jurassic sandstones varies from 1.36 to 1.71 Ga, Permian-Triassic - from 1.14 to 1.35 Ga. Most of the detrital zircon population is of late Paleozoic-early Mesozoic age, approximately 25% are older (pre-Paleoproterozoic). The studied sandstones are mainly rocks of the first cycle of weathering (petrogenic), formed during the erosion of igneous rocks of felsic composition. The synthesis of the obtained data suggests that the main source of the cluster material for the Mesozoic sedimentary rocks was the geological formations of the northern part of the Bureya-Khanka superterrane (Bureya and Malokhingan blocks), as well as, possibly, the eastern part of the Mongol-Okhotsk belt. The Khabarovsk terrane has not drifted significantly along the Tan Lu stike-slip system and is an "autochthonous" block in the present-day structure of Sikhote-Alin.

The Early Cretaceous topographic evolution of Transbaikalia was largely governed by the tectonic evolution of the Mongol-Okhotsk orogen. The collapse of the Mongol-Okhotsk orogen triggered the formation of metamorphic core complexes and associated extensional basins, widespread throughout Transbaikalia, North Mongolia, and North China. Numerous lithofacies and biostratigraphic studies have been carried out from the sedimentary deposits of the Transbaikalia basins. However, the absence of absolute ages for the sedimentary series, as well as sediment source-to-sink analysis do not allow to accurately characterize the regional topographic evolution. We focused our study on the Gusinoozersk Basin of Western Transbaikalia, where extensive sedimentary sections of Lower Cretaceous deposits have been preserved. We provide new U/Pb (LA-ICP-MS) data on detrital zircons from sedimentary series and 40Ar/39Ar data on intruding rocks. We review the paleontological data to clarify the age of the paleogeographic events associated with the collapse of the Mongol-Okhotsk orogen, as well as to correct the age of faunal complexes in Western Transbaikalia. Our geochronological results show that the formation of the Cretaceous basins of Transbaikalia began around 136–130 Ma, accompanying the main episode of extension associated with the exhumation of the metamorphic core complexes. The lowest coarse-clastic formation characterizes the rapid subsidence and the predominance of proximal sediment sources. Distal provinces also made a contribution to sedimentation indicating the rise of a positive topography characterizing the exhumation of the metamorphic core complexes. Overlying fine-grained formations indicate a significant smoothing of the topography, suggesting that from middle Aptian, Western Transbaikalia developed in a relatively calm tectonic regime. We also show that the basins of Transbaikalia were formed both in conjunction with the exhumation of metamorphic cores complexes and reactivated structural sutures. Revised data on dinosaur fauna and palynology, together with the dating of host deposits, provide insights on the Early Cretaceous paleoenvironmental evolution.

This paper deals with the study of syenites and sviatonossites (andradite-bearing syenites) of the Malobystrinsky massif of the Slyudyanka complex (South Baikal region, Siberia), and a large monzonite dike similar in age and composition to the rocks of the massif considered. The studied rocks belong to a series of highly ferriferous and metaluminous A-type granitoids (ASI index <1). They are characterized by SiO 2 45–65 wt. %, K 2 O+Na 2 O up to 12 wt. %, MgO <4 wt. %, TiO 2 up to 2.5 wt. %, and Al 2 O 3 up to 17 wt. %. CaO varies in a wide range, from 2.2 to 14.7 wt. %. The rocks are similar to each other in trace element composition and show patterns with troughs for Th-U, Nb-Ta and Ti. Low-amplitude negative Eu anomaly is observed in the distribution spectra of rare earth elements for the entire rock complex. The obtained Sm-Nd age of sviatonossites in the Malobystrinsky massif is 487.1±6.1 Ma (MSWD=0.99). Our results indicate that syenites and monzonites have εNd (t) –1.9…–2.8, at εSr (t) 21–30, and sviatonossites have εNd (t) –3.8…–4.1 at εSr (t) – 26. Model ages T Nd (DM) for all rock types are Mesoproterozoic (1.3–1.4 Ga). Based on the chemical and Sr-Nd isotopic composition of the magmatic rocks studied, it can be assumed that they have been generated by partial melting of lower crustal rocks (amphibolites). Crystallization of andradite garnet in syenite magma can occur due to melt contamination with metamorphic host rocks of the Slyudyanka complex.

The isotope–geochronological and geochemical data on the age and composition of rocks of the Butugol Block, located in the eastern part of the Tuva–Mongolian microcontinent of the Central Asian Orogenic Belt, have been obtained. It has been established that the protolith for gneisses is, in one case, volcanic rocks with an age of 1009 ± 8 Ma, and in the other case, potassium meta-sedimentary rocks accumulated in continental marginal basins. The protolith of metavolcanogenic rocks of this complex were formed at the turn of the Mesoproterozoic and Neoproterozoic on the already formed crust, while the metasedimentary rocks were formed owing to the Mesoproterozoic, more rarely Paleoproterozoic and Archean, continental provenances. It has been established that the development of the Butugol metamorphic complex (Butugol Block) differs from the development of other blocks of the Earth’s crust included in the composite Tuva–Mongolian microcontinent.

ABSTR A C T Several published Mesoproterozoic paleogeographic reconstructions suggest proximity of northern Laurentia and southern Siberia. However, the apparent absence of the traces of the ca. 1.27 Ga giant Mackenzie magmatic event in southern Siberia was somewhat contradictory to this hypothesis. Here we present geochronological, miner-alogical, geochemical, Nd isotopic, and paleomagnetic data from the Srednecheremshansk dyke-shaped intru-sion, which was recently found in the Sharyzhalgay uplift of the southern part of the Siberian craton and which can be related to the Mackenzie event. The plagioclase-bearing peridotite of this intrusion yielded U-Pb (ID-TIMS) baddeleyite concordia age of 1260 +/- 3 Ma, which is interpreted as the time of their emplacement. This age is close to the previously published baddeleyite age of gabbro from the same intrusion (1258 +/- 5 Ma). The Srednecheremshansk intrusion is composed of ultramafic and mafic rocks. The main rock-forming minerals of the intrusion are olivine, orthopyroxene, clinopyroxene, phlogopite, and plagioclase in various proportions. Sulfide mineralization of the intrusion is represented by pentlandite nodules. The chemical composition of Sredne-cheremshansk ultramafic and mafic rocks correspond to subalkaline peridotite gabbro and gabbro. These rocks are characterized by negative epsilon Nd(t) values range from-6.3 to-6.9. Ultramafic and mafic rocks have similar geochemical and isotopic characteristics, indicating their generation from a single subcontinental lithospheric mantle source. The chemical composition of the Srednecheremshansk intrusion is similar to those of the ca. 1.27 Ga Muskox mafic-ultramafic intrusion of the Mackenzie Large Igneous Province in northern Laurentia. Paleo-magnetic data permit a variety of possible Laurentia-Siberia reconstructions in Mesoproterozoic. The combina-tion of geochronological, geochemical, and paleomagnetic data allows the relation of the Srednecheremshansk intrusion with the Mackenzie magmatic event.

— The paper presents detailed geological, petrographic, geochemical, and isotope data on the dolerites from dykes of the Baikal dike subswarm in the central part of the Baikal basement inlier of the Siberian craton. The main geochemical and isotope criteria were identified for classifying the dolerites that are similar in geological–structural position and mineral composition into three geochemical groups. Provisional age estimates of the dolerites are presented. The dolerites of the first and, perhaps, second groups compose Neoproterozoic (715 Ma) dikes. The first group includes medium- to coarse-grained dolerites, which form thick (more than 5–10 m) dikes. The dolerites of this group are characterized by low concentrations of Th (0.6–2.1 ppm) and Nb (3.3–9.2 ppm) and by ɛNd(T) = ‒0.5 to ‒3.9. Considered together, the geochemical and isotope data show that these dolerites could be produced as a result of the melting of a mantle source produced by mixing mantle components close in composition to oceanic plateau basalts and subduction-related subcontinental lithospheric mantle. The second group includes fine-grained dolerites from thin (1–5 m) dikes, including dikes located in contact with the dikes of the first group. The dolerites of the second group are characterized by higher concentrations of Th (3.0–5.3 ppm) and Nb (9.8–21.1 ppm) and by ɛNd(T) = –5.3 to ‒6.0. Geochemical and isotopic data on the dolerites of the second group indicate that continental crustal material was added to the mantle source unified for the dolerites of first and second groups. The third group includes medium-grained dolerites, which make up individual dikes that are contrastingly different in geochemical and isotope characteristics from the Neoproterozoic dolerites of the first and second groups. Dolerites of this group show low concentrations of Th (0.6–1.6 ppm) and Nb (2.7–5.1 ppm) at low values of (Th/La) pm (0.29–0.71) and 143 Nd/ 144 Nd (0.511223‒0.511544), which indicates that these dolerites may have been generated as a result of the melting of the subcontinental lithospheric mantle enriched in subduction components. Dolerites of the third group exhibit geochemical characteristics close to those of Paleoproterozoic (1.84 Ga) dikes of the South Siberian post-collisional magmatic belt.

Continental rifting is usually viewed in terms of two contrasting models of active and passive extension. The origin of the Baikal Rift, adjacent to the southern part of the Siberian Craton, has been described by both models in the past. It is expected that basaltic magmatism in an active model scenario should be primarily sourced from a mantle plume or plume-fed asthenosphere, whereas melting of the lithospheric mantle is expected to be a predominant source for magmatism in the passive model. In this paper, we focus on the Miocene volcanic rocks sampled along two 60-km-long profiles that cross the boundary between the Neoproterozoic Tuva-Mongolian massif and the Archean-Paleoproterozoic Siberian Craton. Most of the samples studied are trachybasalts. In terms of trace element concentrations normalised to primitive mantle, the lavas mimic oceanic island basalt-like patterns with troughs at Rb, Th-U, Pb, and Y, and peaks at Ba, Nb, Ta, K, and Sr. Moreover, similar trace element patterns to the studied samples are also observed for Miocene and Quaternary lavas located in the southwestern of the Baikal Rift, and adjacent regions of non-rifted Mongolia. According to the ratio of CaO to MgO, and TiO2/Al2O3 to SiO2, the compositions of the studied lavas coincide with experimental melts derived from mafic lithologies. Trace element data of samples suggest that garnet was a residual phase during partial melting. The Sr-Nd isotopic characteristics of the studied lavas are Sr-87/Sr-86 0.70427-0.70469 and 1(43)Nd/Nd-144 0.51267-0.51284. They are identical to the coeval Miocene lavas of neighbouring volcanic fields, but they differ from the Quaternary lavas that extend to lower Sr-87/Sr-86 (0.7038-0.7044) with near identical Nd-143/Nd-144. Isotopes of Hf for studied samples show values epsilon Hf = 6.0-7.7, except for the two samples taken within the boundary between two lithospheric blocks with epsilon Hf 4.6 and 4.8. The delta O-18 of olivine from lava samples is everywhere higher than that of the asthenospheric mantle and ranges from 5.5 to 6.4 parts per thousand. Variations of delta O-18 versus Mg#, Sr-87/Sr-86 and epsilon Hf in the studied samples do not correlate, but do unequivocally rule out crustal assimilation. The isotopic variations are consistent with recycling of mafic crustal lithologies at mantle depths. Lavas from the Tuva-Mongolian massif and the Siberian Craton differ in lead isotopes by lower values of Pb-206/Pb-204 (< 17.785) and higher values of Delta 8/4Pb (61-75) for on-cratonic samples and the reverse relationship for off-cratonic lava (> 17.785 and 55-61), respectively. The equation for Delta 8/4Pb = [Pb-208/Pb-204-(1.209*(Pb-206/Pb-204) +15.627)] *100 is from Hart (Nature, 309, 753-757, 1984). The correlation of lead isotopes with the mafic recycled component, the sharp change of lead isotopic values at the cratonic boundary and decoupling of lead isotope ratios from other isotopic ratios lead us to suggest that the values of Pb-206/Pb-204 and Delta 8/4Pb are associated with an ancient accessory mineral phase such as sulphide confined within the lithospheric mantle. The predominant role of the lithospheric sources in the formation of the Miocene volcanic rocks indicate that the volcanism of the Baikal Rift was caused by a passive tectonic process, rather than active rifting.

The paper discusses data on the elemental composition and 87Sr/86Sr, and δ18O isotopic ratios of feldspar megacrysts collected from lava flows, tuffs, and cinders of three volcanic fields in the Baikal rift system: Iya–Uda, Vitim, and Khamar-Daban, which are located within the early Precambrian, Riphean, and Paleozoic crustal blocks, respectively. Megacrysts are hosted in trachybasalts in the Iya–Uda and Khamar-Daban fields and in basanites in the Vitim field. Megacrysts belong to the following three compositional groups of minerals: (i) plagioclase in lavas of the Iya–Uda field, (ii) anorthoclase in lava flows, tuffs, and cinders of the Khamar-Daban and Vitim fields, and (iii) sanidine in the Vitim field. Elemental and isotope data suggest that megacrysts crystallized in volcanic chambers at different depth levels: anorthoclase crystallized from the most primitive magma with mantle-derived isotopic signatures at subcrustal depth levels, plagioclases were produced in deep crustal chambers during the interaction between mantle-derived magma and crustal rocks, and sanidine was captured from the upper crustal rocks.

In this study, the assessment of uncertainties introduced at different stages of the elemental analysis of archaeological ceramics has been described using the example of the Neolithic pottery sherds from Popovsky Lug (eastern Siberia). To evaluate the uncertainty introduced by sampling due to ceramic heterogeneity, three original sherds were cut into small subsamples. Powdered subsamples (250–350 mg) were analyzed using wavelength-dispersive X-ray fluorescence and inductively coupled plasma mass spectrometry methods, and the variations between analytical results for independent subsamples were compared with the variations introduced during the analytical process (measurement and sample preparation). It was shown that 250–350 mg of ceramic is sufficient to obtain good reproducibility (2–15%) between separate subsamples for most major and trace elements, even for the heterogeneous Neolithic ceramics included in this study. The differing behavior of concentration variations in some elements was explained by measuring the ceramic cross-sections by scanning electron microscopy and micro-X-ray fluorescence spectrometry, as well as by the theoretic modeling of the sampling error. The described workflow can be useful in finding uncertainties in elemental analysis results, which may affect the interpretation of bulk chemical composition in ceramic provenance studies.

Ocher traces on artifacts from the Kovrizhka IV Upper Paleolithic site (Baikal-Patom Highlands, Transbaikal) are studied with micro-X-ray fluorescence analysis (micro-XRF) in the mapping mode. A scraper and microcore from the 6 and 2B cultural horizons of approximately 19.0 and 18.6 thousand years old are considered. A special feature of Kovrizhka IV is the various ocher patterns in the cultural horizons. In particular, ocher stains are visually observed on stone artifacts. The ocher on the surface of artifacts is identified with XRF mapping. The resulting XRF maps indicate the penetration of ocher onto the surfaces, edges, and microcracks of artifacts, which is possible due to prolonged friction. The location of the stains on the samples (before retouching the scraper and on the edges of the core faces) and the painted artifact in the layer in the lowest and earliest position indicate that it appeared at the site already in this form, i.e., they were brought together with ocher. It is concluded that ocher and stone artifacts were transported to the site in the same containers.

The provenance study of archaeological materials is an important step in understanding the cultural and economic life of ancient human communities. One of the most popular approaches in provenance studies is to obtain the chemical composition of material and process it with chemometric methods. In this paper, we describe a combination of the total-reflection X-ray fluorescence (TXRF) method and chemometric techniques (PCA, k-means cluster analysis, and SVM) to study Neolithic ceramic samples from eastern Siberia (Baikal region). A database of ceramic samples was created and included 10 elements/indicators for classification by geographical origin and ornamentation type. This study shows that PCA cannot be used as the primary method for provenance purposes, but can show some patterns in the data. SVM and k-means cluster analysis classified most of the ceramic samples by archaeological site and type with high accuracy. The application of chemometric techniques also showed the similarity of some samples found at sites located close to each other. A database created and processed by SVM or k-means cluster analysis methods can be supplemented with new samples and automatically classified.

—We present results of petrographic, geochemical, and isotope-geochemical (Sm–Nd) studies of the Paleoproterozoic terrigenous rocks of the Urik–Iya graben, which formed during three successive stages of extension. We have established that these rocks are both petrogenic (Ingashi and Daldarma formations) and lithogenic (Ermosokha Formation) sediments. It is concluded that the rocks in the lower and, partly, middle parts of the Urik–Iya graben section (Ingashi Formation and Lower Daldarma Subformation) resulted mostly from the disintegration of felsic igneous rocks. The terrigenous rocks in the middle part of the section (Upper Daldarma Subformation) might have formed through the disintegration of both felsic and mafic igneous rocks. The rocks in the upper part of the section (Ermosokha Formation) probably formed from the underlying terrigenous rocks of the Ingashi and Daldarma formations. The Nd model age (2.3–2.5 Ga) estimated for the rocks of the three studied sections points to a predominance of rocks of the Neoarchean and Paleoproterozoic upper continental crust in the provenance.

The isotopic data showed that there are two stages distinguished in the Cenozoic history of the Darkhad depression volcanic activity, the Late Oligocene initial stage (~28.0–26.6 Ma) and the final Late Miocene – Early Pliocene stage (~5.8–4.2 Ma). It has been stated that the rocks of the initial stage are only represented by trachybasalts; however, among the final-stage basaltoids there are series of shield-volcano hawaite-basanite-phonotephrite rocks and compex trachybasaltic "valley" lava flows, the formation of which is the last stage in the territorial volcanic evolution. It has been shown that the initial-stage trachybasaltic andesites are characterized by their enrichment of TiO 2 , P 2 O 5 , Sr, Zn, Ga and low concentrations of Al 2 O 3 , MnO, CaO, Sc and HREE (La/Yb=27.2–30.2). Basaltoids of the final stage have a similar rare-element distribution and show an increase in the contents of TiO 2 , Al 2 O 3 , P 2 O 5 , LILE, HFSE, Th, U and in the degree of fractionation of REE (La/Yb from 12.2 to 20.9) towards the rocks alkalinity enhancement. Modeling of eclogite, pyroxenite and peridotite melting processes in the La/Yb – Sm/Yb system shows that trachybasaltic andesite melts could be formed at ~7–8 % melting of eclogitic matter or at ~10–11 % melting of Grt-containing pyroxenites, with trachybasalt formed at ~3 % melting of Grt-containing peridotites. The composition distribution of rocks in coordinates (Mg# – Fe/Mn) indicates that the parental magmas are the initial-stage trachybasaltic andesite magmas as well as the Early Pliocene trachybasaltic "valley" lava flows. Sr, Nd, Pb isotope characteristics of the Darkhad depression basaltoids show significant shift of isotopic ratios in time towards the relatively enriched mantle as compared with the depleted MORB mantle. The initial formation of trachybasaltic andesite melts occurred in the Late Oligicene at the pre-rift stage of the territory development involving metasomatized mantle matter, with the pyroxenite or eclogite component contained in the magma formation source. The origin of trachybasalt magmas of the final stage is associated with the processes of decompression melting of peridotites in a weakly metasomatized lithospheric mantle at the rift stage of the Darkhad structure development.