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The Central Asian Orogenic Belt (c. 1000-250 Ma) formed by accretion of island arcs, ophiolites, oceanic islands, seamounts, accretionary wedges, oceanic plateaux and microcontinents in a manner comparable with that of circum-Pacific Mesozoic-Cenozoic accretionary orogens. Palaeomagnetic and palaeofloral data indicate that early accretion (Vendian-Ordovician) took place when Baltica and Siberia were separated by a wide ocean. Island arcs and Precambrian microcontinents accreted to the active margins of the two continents or amalgamated in an oceanic setting (as in Kazakhstan) by roll-back and collision, forming a huge accretionary collage. The Palaeo-Asian Ocean closed in the Permian with formation of the Solonker suture. We evaluate contrasting tectonic models for the evolution of the orogenic belt. Current information provides little support for the main tenets of the one- or three-arc Kipchak model; current data suggest that an archipelago-type (Indonesian) model is more viable. Some diagnostic features of ridge-trench interaction are present in the Central Asian orogen (e.g. granites, adakites, boninites, near-trench magmatism, Alaskan-type mafic-ultramafic complexes, high-temperature metamorphic belts that prograde rapidly from low-grade belts, rhyolitic ash-fall tuffs). They offer a promising perspective for future investigations.

Palaeopascichnida is a problematic group of extinct organisms that is globally distributed in Ediacaran sequences of Avalonia, Baltica, Siberia, South China and Australia. The fossils related to Palaeopascichnida consist of serially or cluster-like arranged, millimetre- to centimetre-scale globular or allantoid chambers, which are characterized by substantial differences in preservation, leading to no consistent diagnosis for these organisms. Here we integrate morphometric variation, stratigraphic distribution and habitat settings of more than 1200 specimens from all known fossil localities. The results of the morphological analysis demonstrate variation in chamber shape and size, and allow us to recognize six valid species within the group. Statistical analysis of the specimen distribution with respect to sedimentary environments indicates a significant difference in palaeoecological settings between species, making a significant contribution to the evolution and systematic palaeontology of these problematic organisms and perspective on their use in Neoproterozoic biostratigraphy. Our revision and systematic study sheds new light on one of the least studied groups of the late Ediacaran biota.

Dating of fungal divergences with molecular clocks thus far has yielded highly inconsistent results. The origin of fungi was estimated at between 660 million and up to 2.15 billion y ago, and the divergence of the two major lineages of higher fungi, Ascomycota and Basidiomycota, at between 390 million y and up to 1.5 billion y ago. Assuming that these inconsistencies stem from various causes, we reassessed the systematic placement of the most important fungal fossil, Paleopyrenomycites, and recalibrated internally unconstrained, published molecular clock trees by applying uniform calibration points. As a result the origin of fungi was re-estimated at between 760 million and 1.06 billion y ago and the origin of the Ascomycota at 500-650 million y ago. These dates are much more consistent than previous estimates, even if based on the same phylogenies and molecular clock trees, and they are also much better in line with the fossil record of fungi and plants and the ecological interdependence between filamentous fungi and land plants. Our results do not provide evidence to suggest the existence of ancient protolichens as an alternative to explain the ecology of early terrestrial fungi in the absence of land plants.

The methodical basis, development, and current state of a new method of chronostratigraphic studies, i.e., strontium isotope stratigraphy (SIS), are considered. This method makes it possible to date and correlate geographically distant sedimentary sequences without involving the biostratigraphic and isotope geochronological data. SIS is based on secular variations in 87Sr/86Sr in the paleocean, resulting from the redistribution of the roles of two global strontium flows formed in the mantle and continental reservoirs of the Earth. Isotopic homogeneity of Sr in the paleoceans and in the linked seas leads to the fact that the 87Sr/86Sr ratio in the sea basins is individual for each geological time point and is inherited in marine chemogenic sediments under deposition of dissolved Sr as an isomorphic impurity. Low-Mg calcite and also fragments of fossilized paleontological remains buried in situ are the best minerals that are capable of retaining the Sr isotopic signature of the sedimentation environment. SIS is carried out with geochemical diagnostics of secondary alteration of the studied material and selective dissolution of the samples to produce a carbonate material that adequately reflects isotopic signature of the sedimentary basin. Interregional correlations of the Proterozoic and Cenozoic sea sediments and their relation to the SIS-based stratigraphic scale are given as an example.

Macroscopic fossils as three-dimension molds and casts of Ediacara-type soft-bodied organisms were found in the Kachergat Formation of the Upper Precambrian Baikal Group of the Western Cisbaikalia for the first time. Among them, the species Palaeopascichnus delicatus and P. linearis of the group palaeopascichnida and Arumberia-type microbially induced sedimentary structures were identified. These findings significantly clarify the age limits of the deposition of the Kachergat Formation and the Baikal Group itself, the stratigraphic position of which in the Upper Precambrian section of Western Cisbaikalia has been controversial.

Data on the first appearances of major animal groups with mineralized skeletons on the Siberian Platform and worldwide are revised and summarized herein with references to an improved carbon isotope stratigraphy and radiometric dating in order to reconstruct the Cambrian radiation (popularly known as the ‘Cambrian explosion’) with a higher precision and provide a basis for the definition of Cambrian Stages 2 to 4. The Lophotrochozoa and, probably, Chaetognatha were first among protostomians to achieve biomineralization during the Terreneuvian Epoch, mainly the Fortunian Age. Fast evolutionary radiation within the Lophotrochozoa was followed by radiation of the sclerotized and biomineralized Ecdysozoa during Stage 3. The first mineralized skeletons of the Deuterostomia, represented by echinoderms, appeared in the middle of Cambrian Stage 3. The fossil record of sponges and cnidarians suggests that they acquired biomineralized skeletons in the late Neoproterozoic, but diversification of both definite sponges and cnidarians was in parallel to that of bilaterians. The distribution of calcium carbonate skeletal mineralogies from the upper Ediacaran to lower Cambrian reflects fluctuations in the global ocean chemistry and shows that the Cambrian radiation occurred mainly during a time of aragonite and high-magnesium calcite seas.

Macroscopic fossils as composite molds and casts of Ediacara-type soft-bodied organisms were found in the Dzhezhim Formation of the Timan Range for the first time. Among them, representatives of palaeopascichnids, arboreomorphs, chuariomorphids, microbial colonies, and trace fossils were identified. This finding of such a large number of various Ediacaran fossils on the Timan Range not only develops our understanding of their paleogeographic range but also clarifies the age limits of the deposition of the Dzhezhim Formation, the stratigraphic position of which in the Upper Precambrian section was controversial.

The complex body-trace fossils of Vendian soft-bodied biota have been found for the first time in the Central Urals during the study of the Vilukha and Sinii Kamen members of the Chernyi Kamen Formation of the Upper Vendian Sylvitsa Group (Kos’va River area, Perm Krai of Russia). These sedimentary sequences were exposed along the valley of the Shirokovskii Reservoir. Among the fossils, the chuariomorpha-like species Beltanelliformis konovalovi , previously described from the Konovalovka Member of the Chernyi Kamen Formation, was identified. However, the morphological analysis of the new fossil material revealed a number of principal differences from representatives of the genus Beltanelliformi s Menner, 1974. It was shown that the taxon B. konovalovi , most likely, does not belong to this genus and probably needs further revision, and, in turn, the fossil locality at the Shirokovskii Reservoir allows us to establish a new area with fossils of the Precambrian mobile organisms.

Macrofossils of the Vendian soft-bodied organisms were found for the first time in the Vizinga and Ust’-Palega formations of the Upper Precambrian in Chetlasskii Kamen Hill (Middle Timan, Arkhangelsk oblast). Representatives of palaeopascichnids, aspidellamorphs, and possible frondomorphs, trace fossils, and microbially induced arumberiamorph structures were identified among molds and three-dimensional casts of fossils. Previously we revealed Vendian macrofossils in the Upper Precambrian in Dzhezhim-Parma Hill (South Timan, Komi Republic). The discovery of one more locality of various Ediacaran fossils in the middle part of the Timan Ridge significantly expands their paleogeography and also clarifies the time frame of deposition of the Vizinga and Ust’-Palega formations, the position of which in the Upper Precambrian section of Central Timan was debatable.

The article presents the results of study of some general features of the evolution of bulk chemical composition of clay rocks of the Upper Precambrian sedimentary groups of South Urals, which indicate the composition of source rocks of their alumosilicoclastic material (ln(Ni/Co) and ln(Th/Sc) values) and paleogeodynamic settings of formation (discriminant functions DF1 and DF2). Our conclusions are compared with ideas on the formation of these groups, which are based on general geological data and analysis of the formational nature of volcanic rocks known in some levels of the Riphean stratotype. It is considered in the last few decades that the Yurmatau and Karatau or Burzyan and Yurmatau groups have rift-related depression/platform origin. This suggests that their sedimentary complexes formed similarly and should be reflected in lithogeochemical characteristics of the latter. It is shown that the architecture of the Upper Precambrian sedimentary groups of the South Urals is largely diverse in terms of the “lithochemistry of fine-grained clastic rocks–paleogeodynamics”. The trends of the variation in bulk chemical composition of clay rocks in each groups in the DF1–DF2 diagram are not comparable in most cases with the model “sedimentary rocks of rift-related settings → the same of platform settings” trend. In the ln(Ni/Co)–ln(Th/Sc) diagram, the clay rocks of the sedimentary groups are characterized by two types of variation in bulk chemical composition. Each group is specific in these parameters. Thus, the features of bulk chemical composition of clay rocks, which are caused by the composition of the provenance rocks, exhibit no similar variation trends from bottom to top along the sedimentary group. It is evident that all the aforesaid indicates a significant role of paleogeodynamics and the composition of the provenances, as well as numerous (?) local factors in the formation of sedimentary filling of the Early, Middle, and Late Riphean, as well as Vendian, sedimentary basins of the South Urals.