Abstract: In 1841, Murchison coined the term Permian for strata in the Russian Urals. Recognition of the Permian outside of Russia and central Europe soon followed, but it took about a century for the Permian to be accepted globally as a distinct geological system. The work of the Subcommission on Permian Stratigraphy began in the 1970s and resulted in current recognition of nine Permian stages in three series: the Cisuralian (lower Permian) – Asselian, Sakmarian, Artinskian and Kungurian; the Guadalupian (middle Permian) – Roadian, Wordian and Capitanian; and the Lopingian (upper Permian) – Wuchiapingian and Changhsingian. The 1990s saw the rise of Permian conodont biostratigraphy, so that all Permian Global Stratigraphic Sections and Points (GSSPs) use conodont evolutionary events as the primary signal for correlation. Issues in the development of a Permian chronostratigraphic scale include those of stability and priority of nomenclature and concepts, disagreements over changing taxonomy, ammonoid v. fusulinid v. conodont biostratigraphy, differences in the perceived significance of biotic events for chronostratigraphic classification, and correlation problems between provinces. Further development of the Permian chronostratigraphic scale should focus on GSSP selection for the remaining, undefined stage bases, definition and characterization of substages, and further integration of the Permian chronostratigraphic scale with radioisotopic, magnetostratigraphic and chemostratigraphic tools for calibration and correlation.

Abstract: Establishing a Permian brachiopod biochronological scheme for global correlation is difficult because of strong provincialism during the Permian. In this paper, a brief overview of brachiopod successions in five major palaeobiogeographical realms/zones is provided. For Gondwanaland and peri-Gondwanan regions including Cimmerian blocks, Bandoproductus and Punctocyrtella (or Cyrtella ) are characteristic of the lower Cisuralian, as is Cimmeriella for the middle Cisuralian. As the Cimmerian blocks continued drifting north during the late Kungurian, accompanied by climate amelioration, contemporaneous brachiopods inhabiting these blocks showed a distinct shift from cold-water to mixed or warm-water affinities. However, coeval brachiopods in the Northern Transitional Zone (NTZ) are characterized by warm-water faunas and are associated with fusulinids in the lower Cisuralian. The Guadalupian brachiopods of the NTZ were clearly mixed between the Boreal and palaeoequatorial affinities. The end-Guadalupian is marked by the disappearance of a few characteristic genera, such as Vediproductus , Neoplicatifera and Urushtenoidea , in the Palaeotethyan region. The onset of the end-Permian mass extinction in the latest Changhsingian is clearly exhibited by the occurrence of the dwarfed and thin-shelled brachiopods commonly containing Paracrurithyris .

Abstract The NW–SE-trending Pai-Khoi fold–thrust belt links the Permian Uralian Orogen in the Polar Urals with the early Mesozoic fold belt on Novaya Zemlya. An interpretation of structural lineaments present in southern Novaya Zemlya suggests that the NW–SE-trending fold belt in southernmost Novaya Zemlya may have formed contemporaneously with parallel sinistral strike-slip faults. Analysis of regional-scale geological maps of the adjacent Pai-Khoi fold–thrust belt reveals large-scale structural relationships indicative of sinistral shear along the fold–thrust belt, including the presence of left-stepping en echelon folds within the Kara Shale Allochthon. This interpretation is corroborated by a field study of the allochthon-bounding Main Pai-Khoi Thrust, which reveals a consistently oblique tectonic stretching lineation, pitching 56° towards the east, suggesting tectonic displacement towards the west. It is therefore proposed that the Pai-Khoi fold–thrust belt is best described as a zone of sinistral inclined transpression. The interpretation of the Pai-Khoi fold–thrust belt as a zone of sinistral transpression has important implications for the interpretation of this tectonic boundary. This is reflected in a new structural cross-section through southernmost Novaya Zemlya, which is characterized by thick-skinned tectonics and steep strike-slip faults. These faults may link at depth with the Baidaratsky Fault.

Abstract: Permian rugose corals underwent evolutionary episodes of assemblage changeover, biogeographical separation and extinction, which are closely related to geological events during this time. Two coral realms were recognized, the Tethyan Realm and the Cordilleran–Arctic–Uralian Realm. These are characterized by the families Kepingophyllidae and Waagenophyllidae during the Cisuralian, Waagenophyllidae in the Guadalupian and the subfamily Waagenophyllinae in the Lopingian, and the families Durhaminidae and Kleopatrinidae during the Cisuralian and major disappearance of colonial and dissepimented solitary rugose corals from the Guadalupian to the Lopingian, respectively. The development of these coral realms is controlled by the geographical barrier resulting from the Pangaea formation. According to the changes in the composition and diversity of the Permian rugose corals, a changeover event might have occurred at the end-Sakmarian and is characterized by the mixed Pennsylvanian and Permian faunas to typical Permian faunas, probably related to a global regression. In addition, three extinction events are present at the end-Kungurian, the end-Guadalupian and the end-Permian, which are respectively triggered by the northward movement of Pangaea, the Emeishan volcanic eruptions and subsequent global regression, and the global climate warming induced by the Siberian Traps eruption.

Abstract Radon-222 and carbon dioxide (CO 2 ) emissions were studied around four remote Nepalese thermal springs near the Main Central Thrust: Timure and Chilime in the upper Trisuli Valley, central Nepal; and Sulighad and Tarakot in Lower Dolpo, western Nepal. A total of 279 radon fluxes and 670 CO 2 fluxes were measured on the ground, complemented by radon concentration measurements in soil and water, and assisted by thermal infrared imaging. In Lower Dolpo, mean radon fluxes ranging from 270×10 −3 to 450×10 −3 Bq m −2 s −1 , radon concentration in water greater than 100 Bq l −1 , low mean CO 2 fluxes (18–32 g m −2 day −1 ), and integrated radon and CO 2 discharges of 70–180 Bq s −1 and (2.3–3.8)×10 −3 mol s −1 , respectively, suggest shallow-water-dominated transport with simultaneous radon and CO 2 degassing from the hydrothermal water. In the upper Trisuli Valley, mean radon fluxes ranging from 140×10 −3 to 570×10 −3 Bq m −2 s −1 , larger mean CO 2 fluxes that range from 430 to 2930 g m −2 day −1 , radon concentration in water of less than 6 Bq l −1 , and integrated radon and CO 2 discharges of 290–840 Bq s −1 and (390–830)×10 −3 mol s −1 , respectively, indicate fast gas-dominated transport of deep metamorphic-origin CO 2 charged in radon along a fault network. Radon can thus give precious information on the gas transport properties of the shallow continental crust. Supplementary material: Additional radon and carbon dioxide flux measurement profiles are available at https://doi.org/10.6084/m9.figshare.c.3582128

Abstract This paper considers the lithospheric structure and evolution of the wider Barents–Kara Sea region based on the compilation and integration of geophysical and geological data. Regional transects are constructed at both crustal and lithospheric scales based on the available data and a regional three-dimensional model. The transects, which extend onshore and into the deep oceanic basins, are used to link deep and shallow structures and processes, as well as to link offshore and onshore areas. The study area has been affected by numerous orogenic events in the Precambrian–Cambrian (Timanian), Silurian–Devonian (Caledonian), latest Devonian–earliest Carboniferous (Ellesmerian–svalbardian), Carboniferous–Permian (Uralian), Late Triassic (Taimyr, Pai Khoi and Novaya Zemlya) and Palaeogene (Spitsbergen–Eurekan). It has also been affected by at least three episodes of regional-scale magmatism, the so-called large igneous provinces: the Siberian Traps (Permian–Triassic transition), the High Arctic Large Igneous Province (Early Cretaceous) and the North Atlantic (Paleocene–Eocene transition). Additional magmatic events occurred in parts of the study area in Devonian and Late Cretaceous times. Within this geological framework, we integrate basin development with regional tectonic events and summarize the stages in basin evolution. We further discuss the timing, causes and implications of basin evolution. Fault activity is related to regional stress regimes and the reactivation of pre-existing basement structures. Regional uplift/subsidence events are discussed in a source-to-sink context and are related to their regional tectonic and palaeogeographical settings.

Diamond genesis can be clarified by estimating the common parental media for diamond and its syngenetic inclusions. Formation of diamond and diamondite in carbonatitic melts with garnets, clinopyroxenes, carbonates, iron-chromium alloys, and other minerals was confirmed in experiments using diamond-bearing Kokchetav (Kazakhstan) and Chagatai (Uzbekistan) carbonatitic rocks as the starting materials. Experiments on melting equilibrium of an eclogitic garnet-pyrrhotite join at 7 GPa revealed the existence of a nearly complete silicate-sulfide liquid immiscibility. Very low solubility of silicate components in the sulfide melt implies that the melt is not so efficient for syngenesis of diamonds and silicate inclusions, whereas carbonatitic (carbonate-silicate) parental melts can provide syngenesis of diamond and their primary inclusions more viably. The major components of the parental media for diamond syngenesis are carbonates and silicates, and the minor components are oxides, sulfides, phosphates, haloids, carbon dioxide, water, etc. These media are partially or completely molten during diamond formation, and they have compositionally variable major and minor component contents. It is obvious that the parental media for diamond is closely related to the genesis of carbonatitic magmas in the Earth's mantle.

We discuss the Late Neoproterozoic and Vendian and Cambrian evolution of sedimentary basins and regional deposition events in the southwestern and southern margins of the Siberian craton from the Igarka region in the lower reaches of the Yenisei to the Patom Upland northeast of Lake Baikal. The deposition history between ca. 750 and 543 Ma was reconstructed using correlation of Late Neoproterozoic sediments with regard to diamictite deposited during global Sturtian and Varangerian glacials, rifting and collisional events, and eustatic sea level fluctuations. The accretionary and collisional events of 880–750 Ma were followed by the breakup of the supercontinent that included Siberia and the inception of failed rifts in the territory of the Yenisei Ridge, the Sayan and Baikal regions, and the Patom Upland. The main rifting stage was associated with the formation of the passive continental margin and high-energy tidal deposition on widespread broad shelves. The earliest Vendian (Ediacaran) was marked by the onset of another accretionary stage when marine deposition was disturbed by regional-scale continental glaciation (the Varangerian glacial epoch) and deep exaration of Late Riphean shelves. Vendian climate and tectonic events are reflected in the evolution of a peripheral foreland basin on the craton margin that went through several stages: (1) Early–Late Vendian subduction, glaciation, and then terrigenous carbonate shelf deposition (ca. 600 Ma). Subduction was accompanied by transgression of the fringing seas onto the craton and centrifugal transport of clastics. (2) Late Vendian collision and accretion, growth of bordering orogens, and continental molasse deposition (ca. 550 Ma). The collisional processes interrupted the marine deposition of the previous stage, closed the remnant marginal basins, and produced a peripheral orogen of a great extent. Deposition was on broad alluvial plains, and clastics were transported centripetally. (3) Late Vendian–Early Cambrian rifting and subsidence of a hangingwall clastic basin (ca. 543 Ma). Plate reorganization caused extension and related rifting and doming on the craton. The hangingwall basin on the slopes of domes received clastics from new sources on the uplifted basement blocks on the craton periphery. The dispersal of the collision-accretionary collage (the Vendian Pannotia continent) was completed in the Early–Middle Cambrian by the formation of carbonate platforms and an evaporite basin.

Hydroxyl (OH) content in diopside of one diamond-free ultrahigh-pressure (UHP) marble from the Kokchetav Massif, Kazakhstan, was estimated by a micro–Fourier transform infrared (FTIR) spectrometer. Two intrinsic diopside OH bands of FTIR absorption spectra were identified at 3645 and 3465 cm −1 , with the former band dominating the spectra. Another band occurred at 3685 cm −1 , which seemed to be accompanied by trivial bands at 3750, 3730, 3585, and 3565 cm −1 . Intensity variation of the 3685 cm −1 band within a single diopside crystal and its location may suggest that the cause of this band was submicroscopic amphibole lamellae. The OH concentration of diopside was estimated to be no less than 850 ppm by weight. Using the previously published experimental data, this OH content indicates that diopside formed at pressures >5 GPa and in a high water activity ( a H 2 O) environment.