Reconstruction of tectonic events on the northern Eurasia margin of the Arctic, from U-Pb detrital zircon provenance investigations of late Paleozoic to Mesozoic sandstones in southern Taimyr Peninsula

2015 ◽  
pp. B31241.1 ◽  
Author(s):  
Xiaojing Zhang ◽  
Victoria Pease ◽  
Jakob Skogseid ◽  
Cora Wohlgemuth-Ueberwasser
Keyword(s):  
Detrital Zircon ◽  
The Arctic ◽  
Late Paleozoic ◽  
Northern Eurasia ◽  
Taimyr Peninsula ◽  
Tectonic Events

scholarly journals Provenance of Late Paleozoic-Mesozoic Sandstones, Taimyr Peninsula, the Arctic

Geosciences ◽  
2013 ◽  
Vol 3 (3) ◽  
pp. 502-527 ◽  
Author(s):  
Xiaojing Zhang ◽  
Jenny Omma ◽  
Victoria Pease ◽  
Robert Scott
Keyword(s):  
The Arctic ◽  
Late Paleozoic ◽  
Taimyr Peninsula

Late Weichselian Ice Sheet of Northern Eurasia

1980 ◽  
Vol 13 (1) ◽  
pp. 1-32 ◽  
Author(s):  
M. G. Grosswald
Keyword(s):  
Continental Shelf ◽  
Sea Level ◽  
Ice Sheet ◽  
West Siberia ◽  
The Arctic ◽  
Russian Plain ◽  
Northern Eurasia ◽  
Taimyr Peninsula ◽  
Continental Shelves ◽  
Late Weichselian

AbstractA considerable portion of Northern Eurasia, and particularly its continental shelf, was glaciated by inland ice during late Weichsel time. This was first inferred from such evidence as glacial striae, submarine troughs, sea-bed diamictons, boulder trains on adjacent land, and patterns of glacioisostatic crustal movements. Subsequently, the inference was confirmed by data on the occurrence and geographic position of late Weichselian end moraines and proglacial lacustrine deposits.The south-facing outer moraines in the northeastern Russian Plain, northern West Siberia, and on Taimyr Peninsula are underlain by sediments containing wood and peat, the radiocarbon dating of which yielded ages of 22,000 to 45,000 yr B.P. The youngest late-glacial moraines are of Holocene age: the double Markhida moraine in the lower Pechora River basin, presumably associated with “degradational” surges of the Barents Ice Dome, is underlain by sediments with wood and peat dated at 9000 to 9900 yr B.P.: this suggests that deglaciation of the Arctic continental shelf of Eurasia was not completed until after 9000 yr B.P.The reconstructed ice-front lines lead to the conclusion that the late Weichselian ice sheet of Northern Eurasia (proposed name: theEurasian Ice Sheet) extended without interruptions from southwestern Ireland to the northeastern end of Taimyr Peninsula, a distance of 6000 km: it covered an area of 8,370,000 km2, half of which lay on the present-day continental shelves and a quarter on lowlands that were depressed isostatically below sea level. Hence, the ice sheet was predominantly marine-based.A contour map of the ice sheet based both on the dependence of the heights of ice domes upon their radii and on factual data concerning the impact of bedrock topography upon ice relief has been constructed. The major features of the ice sheet were the British, Scandinavian, Barents, and Kara Ice Domes that had altitudes of 1.9 to 3.3 km and were separated from one another by ice saddles about 1.5 km high. At the late Weichselian glacial maximum, all the main ice-dispersion centers were on continental shelves and coastal lowlands, whereas mountain centers, such as the Polar Urals and Byrranga Range, played only a local role.The portions of the ice sheet that were grounded on continental shelves some 700 to 900 m below sea level were inherently unstable and could exist only in conjunction with confined and pinned floating ice shelves that covered the Arctic Ocean and the Greenland and Norwegian Seas.The Eurasian Ice Sheet impounded the Severnaya Dvina, Mezen, Pechora, Ob, Irtysh, and Yneisei Rivers, and caused the formation of ice-dammed lakes on the northern Russian Plain and in West Siberia. Until about 13,500 yr B.P. the proglacial system of lakes and spillways had a radial pattern; it included large West Siberian lakes, the Caspian and Black Seas, and ended in the Mediterranian Sea. Later, the system became marginal and discharged proglacial water mainly into the Norwegian Sea.

scholarly journals Late Paleozoic–Early Mesozoic Granite Magmatism on the Arctic Margin of the Siberian Craton during the Kara-Siberia Oblique Collision and Plume Events

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 571
Author(s):  
Valery A. Vernikovsky ◽  
Antonina Vernikovskaya ◽  
Vasilij Proskurnin ◽  
Nikolay Matushkin ◽  
Maria Proskurnina ◽  
...  
Keyword(s):  
The Arctic ◽  
Late Paleozoic ◽  
Taimyr Peninsula ◽  
Oblique Collision ◽  
Early Mesozoic ◽  
Plume Magmatism ◽  
Granite Magmatism ◽  
Mesozoic Granite ◽  
Early Middle Triassic ◽  
The Relationship

We present new structural, petrographic, geochemical and geochronological data for the late Paleozoic–early Mesozoic granites and associated igneous rocks of the Taimyr Peninsula. It is demonstrated that large volumes of granites were formed due to the oblique collision of the Kara microcontinent and the Siberian paleocontinent. Based on U-Th-Pb isotope data for zircons, we identify syncollisional (315–282 Ma) and postcollisional (264–248 Ma) varieties, which differ not only in age but also in petrochemical and geochemical features. It is also shown that as the postcollisional magmatism was coming to an end, Siberian plume magmatism manifested in the Kara orogen and was represented by basalts and dolerites of the trap formation (251–249 Ma), but also by differentiated and individual intrusions of monzonites, quartz monzonites and syenites (Early–Middle Triassic) with a mixed crustal-mantle source. We present a geodynamic model for the formation of the Kara orogen and discuss the relationship between collisional and trap magmatism.

Сlassification of vegetation of baidzharakh massifs in two sites of the arctic tundra subzone in the Siberian sector of the Russian Arctic

2020 ◽  
pp. 75-99
Author(s):  
O. I. Sumina
Keyword(s):  
Vascular Plants ◽  
Plant Cover ◽  
Arctic Tundra ◽  
The Arctic ◽  
Taimyr Peninsula ◽  
Vegetation Diversity ◽  
Bay Area ◽  
Open Ground ◽  
Crustose Lichens ◽  
Northeast Coast

One of the thermokarst relief forms is baidzharakh massif — the group of mounds separated by trenches formed as a result of the underground ice-wedge polygonal networks melting (Fig. 1). Study of baidzharakh vegetation took place on the northeast coast of the Taimyr Peninsula (the Pronchishcheva Bay area) and on the New Siberian Islands (the Kotelny Island) in 1973–1974 (Sumina, 1975, 1976, 1977a, b, 1979 et al.). The aim of this paper is to produce the classification of baidzharakh mound and trenches communities according to the Brown-Blanquet approach (Westhoff, Maarel, 1978) and to compare these data with the community types earlier established on domination principle (Sumina, 1975 et al.). The information obtained in the 1970s could be helpful in a comparative assessment of the thermokarst process dynamics over the past 4 decades, as well as for comparing these processes in other regions of the Arctic. Both studied areas are located in the northern part of the arctic tundra subzone. On the Taimyr Peninsula (and in particular in the Pronchishcheva Bay area) the plakor (zonal) communities belong to the ass. Salici polaris–Hylocomietum alaskani Matveyeva 1998. Our relevés of plakor tundra on the Kotelny Island demonstrate similarity with the zonal communities of the northeast coast of the Taimyr Peninsula (Table 2). Relevés of communities of thermokarst mounds were made within their boundaries, the size of ~ 30 m². In trenches sample plots of the same area had rectangular shape according to trench width. Relevés of plakor tundra were made on 5x6 m plots. There were marked: location in relief, moistening, stand physiognomy, nanorelief, the percent of open ground patches and degree of their overgrowing, total plant cover, that of vascular plants, mosses, and lichens (especially — crustose ons), and cover estimates for each species. The shape of thermokarst mounds depends on the stage of thermodenudation processes. Flat polygons about 0.5 m height with vegetation similar to the plakor tundra are formed at the beginning of ice melting (Fig. 3, a), after which the deformation of the mounds (from eroded flat polygon (Fig. 3, b) to eroded conical mound (Fig. 3, c). Such mounds of maximal height up to 5 m are located on the middle part of steep slopes, where thermodenudation is very active. The last stage of mound destruction is slightly convex mound with a lumpy surface and vegetation, typical to snowbed sites at slope foots (Fig. 3, d, and 5). Both on watersheds and on gentle slopes mounds are not completely destroyed; and on such elongated smooth-conical mounds dense meadow-like vegetation is developed (Fig. 6). On the Kotelny Island thermokarst mounds of all described shapes occur, while in the Pronchishcheva Bay area only flat polygons, eroded flat polygons, and elongated smooth-conical mounds are presented. Under the influence of thermodenudation the plakor (zonal) vegetation is being transformed that allows to consider the most of mound and trench communities as the variants of zonal association. On the base of 63 relevés, made in 14 baidzharakh massifs, 2 variants with 7 subvariants of the ass. Salici polaris–Hylocomietum alaskani Matveyeva 1998 were established, as well as 1 variant of the azonal ass. Poo arcticae– Dupontietum fisheri Matveyeva 1994, which combines the vegetation of wet trenches with dense herbmoss cover. A detailed description of each subvariant is done. All these syntaxa are compared with the types of mound and trenh communities established previously by the domination principle (Sumina, 1975, 1976, 1979 et al.) and with Brown-Blanquet’ syntaxa published by other authors. The Brown-Blanquet approach in compare with domination principle, clearly demonstrates the similarity between zonal and baidzharakh massifs vegetation. Diagnostic species of syntaxa of baidzharakh vegetation by other authors (Matveyeva, 1994; Zanokha, 1995; Kholod, 2007, 2014; Telyatnikov et al., 2017) differ from ours. On the one hand, this is due to the fact that all mentioned researchers worked in another areas, and on the other, with different hierarchial levels of syntaxa, which are subassociations (or vicariants) in cited works or variants and subvariants in the our. Communities of mounds as well as of trenches in different regions have unlike species composition, but similar apearance, which depends on the similarity of the life form composition and community pattern, stage of their transformation and environmental factors. This fact is a base to group communities by physiognomy in order to have an opportunity of comparative analysis of baidzharakh vegetation diversity in different regions of the Arctic. In total, 6 such groups for thermokarst mounds and trenches are proposed: “tundra-like” ― vegetation of flat polygonal mounds (or trenches) is similar to the plakor (zonal) communities; “eroded tundra-like” ― tundra-like vegetation is presented as fragments, open ground occupies the main part of flat polygonal mounds; “eroded mounds with nonassociated vegetation” ― eroded mounds of various shapes up to sharp conical with absent vegetation at the top and slopes, sparse pioneer vascular plants on a bare substrate and crustose lichens and chionophilous grasses at foots; “meadow-like” ― herb stands with a participation of tundra dwarf-shrubs, mosses, and lichens on elongated smooth-conical mounds and in moderately moist trenches; “communities in snowbeds” ― thin plant cover formed by small mosses, liverworts, crustose lichens, and sparse vascular plants in snowbed habitats on destroyed slightly convex mounds with a lumpy surface and in trenches; “communities of cotton grass” or others, depending on the dominant species ― in wet trenches where vegetation is similar to the arctic hypnum bogs with dominant hygrophyte graminoids as Eriophorum scheuchzeri, E. polystachion, Dupontia fischeri et al. This sheme according to physiognomic features of thermokarst mound and trench communities, as a simplier way to assess the current dynamic stage of the baidzharakh massifs, may be useful for monitoring the thermodenudation activity in different areas of the Arctic, particularly in connection with observed climate changes (ACIA, 2004) and a possible dramatic “cascade of their environmental consequences” (Fraser et al., 2018).

New Evidence of the Late Neopleistocene Peopling of the Lower Ob Valley

2021 ◽  
Vol 49 (1) ◽  
pp. 9-20
Author(s):  
I. D. Zolnikov ◽  
A. A. Anoikin ◽  
E. A. Filatov ◽  
A. V. Vybornov ◽  
A. V. Vasiliev ◽  
...  
Keyword(s):  
Upper Paleolithic ◽  
The Arctic ◽  
Northern Eurasia ◽  
West Siberian Plain ◽  
Faunal Remains ◽  
Human Occupation ◽  
Large Area ◽  
Paleolithic Site ◽  
The North ◽  
Available Information

This study focuses on the early human occupation of the arctic part of the West Siberian Plain and introduces the finds at the Paleolithic site Kushevat (Shuryshkarsky District, Yamal-Nenets Autonomous Okrug), discovered in 2020. Geological and geomorphological characteristics of the Lower Ob region are provided, the chronology of the key Middle and Late Neopleistocene sequences is assessed, and criteria underlying the search for Paleolithic sites in the area are outlined. We describe the discovery and excavations at Kushevat, its stratigraphy and its faunal remains. On the basis of correlation with neighboring key Late Neopleistocene sections with a representative series of absolute dates, the age of the site is estimated at cal 50–35 ka BP. Results of a traceological study of a possibly human-modified reindeer antler are provided. Findings at Kushevat and the available information on the early peopling of northern Eurasia suggest that the boundary of the inhabited part of that region must be shifted ~200 km to the north. The Ob, therefore, is one of the last major Siberian rivers where traces of the Early Upper Paleolithic culture have been found. The discovery of a stratified site in its lower stretch is a milestone in the Paleolithic studies in the region. A large area over which faunal remains are distributed, and the presence of lithics among the surface finds, suggest that Kushevat is a highly prospective site for future archaeological studies of the early stages in the human peopling of the region.

Chapter 6 Conclusions, differences between the Jabal Akhdar and Saih Hatat domes and unanswered questions

10.1144/m54.6 ◽  
2021 ◽  
Vol 54 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Andreas Scharf ◽  
Frank Mattern ◽  
Mohammed Al-Wardi ◽  
Gianluca Frijia ◽  
Daniel Moraetis ◽  
...  
Keyword(s):  
Large Scale ◽  
Late Paleozoic ◽  
Future Research ◽  
Early Paleozoic ◽  
Chronological Order ◽  
Oman Mountains ◽  
Tectonic Events ◽  
Major Fault ◽  
Tethys Ocean ◽  
Semail Ophiolite

AbstractThis chapter provides the conclusions/outlines of the tectonics, affecting the Southeastern Oman Mountains, including the Jabal Akhdar and Saih Hatat domes. The main tectonic events include amongst others (1) Neoproterozoic rifting, (2) two distinct early Paleozoic compressive events, (3) large-scale open ‘Hercynian’ folding and formation of a pronounced unconformity during the late Paleozoic, (4) rifting preceding the opening of the Neo-Tethys Ocean during the late Paleozoic, (5) late Cretaceous obduction of the Semail Ophiolite and the response of the Arabian lithosphere as well as (6) post-obductional tectonics. Also of major geological significance are the three major glaciations (Sturtian, Marinoan and Late Paleozoic Gondwana glaciation) which have been recorded in the rocks of northern Oman. Moreover, major lithological, structural and metamorphic differences exist between the Jabal Akhdar and Saih Hatat domes. It appears likely that a major fault, striking parallel to the eastern margin of the Jabal Akhdar Dome, probably originating during Neoproterozoic terrain accretion, acted as a divide between both domes until present. This fault was multiple times reactivated and could explain the differences between the two domes. A catalogue of unanswered questions is included in chronological order to express that many geological aspects need further investigation and future research projects.

Accurate continuous observations of carbon dioxide and methane dry mole fractions in the arctic atmosphere near the Dikson settlement, Siberia

2021 ◽  
Author(s):  
Alexey Panov ◽  
Anatoly Prokushkin ◽  
Jošt Lavrič ◽  
Karl Kübler ◽  
Mikhail Korets ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Basic Research ◽  
Local Environment ◽  
The Arctic ◽  
Taimyr Peninsula ◽  
Data Quality Control ◽  
Max Planck ◽  
Frozen Ground ◽  
Gas Measurements ◽  
Arctic Atmosphere

<div> <p><span>Measurements of the atmospheric sources and sinks of carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) in the pan-Arctic domain are extremely sparse that limits our knowledge of carbon cycling over this dramatically sensitive environment and making predictions about a fate of carbon conserved in currently frozen ground. Especially critical are the gaps in the arctic latitudes of Siberia, covered by the vast permafrost underlain tundra, where only few continuous atmospheric observation stations are currently operational.</span></p> </div><div> <p><span>We present the first two years of accurate continuous observations of atmospheric CO<sub>2</sub> and CH<sub>4</sub> dry mole fractions at the new atmospheric carbon observation station located near the Dikson settlement (73.33° N, 80.34° E) on the seashore of the western part of the Taimyr Peninsula in Siberia. Data quality control of trace gas measurements is achieved by regular calibrations against WMO-traceable reference gases from pressurized dry air tanks filled at the Max Planck Institute for Biogeochemistry (Jena, Germany). Associated meteorological variables permit evaluation of the climate variability of the local environment and provide a background for screening and interpreting the greenhouse gases (GHG) data records. </span><span>Here we summarize the scientific rationale of the new site, give technical details of the instrumental setup, analyse the local environments and present CO</span><sub>2</sub><span> and CH</span><sub>4</sub><span> fluctuations in the arctic atmosphere. Along with the temporal variability of GHG’s, we provide an overview of the angular distribution of detected GHG signals in the region and their input to the atmospheric fluctuations on the measurement site. Observation records deal with the daytime mixed layer and may be considered as representative throughout the vast area (~500–1000 km), and cover the period from September 2018 to September 2020.</span></p> </div><div> <p><span>The </span><span>reported study</span><span> was funded by Russian Foundation for Basic Research, Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science, project number 20-45-242908, RFBR project </span><span>18-05-60203</span><span> and </span><span>by the Max Planck Society (Germany)</span></p> </div>

Late Paleozoic tectonism of the Bogda region in  Chinese North Tianshan: Insights from sedimentary provenance analysis

2021 ◽  
Author(s):  
Qian Wang ◽  
Guochun Zhao ◽  
Yigui Han ◽  
Jinlong Yao
Keyword(s):  
Detrital Zircon ◽  
Detrital Zircons ◽  
Late Paleozoic ◽  
Provenance Analysis ◽  
The North ◽  
Tectonic Transition ◽  
Isotopic Analyses ◽  
Zircon Morphology ◽  
Detrital Zircon Ages ◽  
T Values

<p>The Chinese North Tianshan (CNTS) extends E-W along the southern part of the Central Asian Orogenic Belt and has undergone complicated accretion-collision processes in the Paleozoic. This study attempts to clarify the late Paleozoic tectonism in the region by investigating the provenance of the Late Paleozoic sedimentary successions from the Bogda Mountain in the eastern CNTS by U-Pb dating and Lu-Hf isotopic analyses of detrital zircons. Detrital zircon U-Pb ages (N=519) from seven samples range from 261 ± 4 Ma to 2827 ± 32 Ma, with the most prominent age peak at 313 Ma. There are Precambrian detrital zircon ages (~7%) ranged from 694 to 1024 Ma. The youngest age components in each sample yielded weighted mean ages ranging from 272 ± 9 Ma to 288 ± 5 Ma, representing the maximum depositional ages. These and literature data indicate that some previously-assumed “Carboniferous” strata in the Bogda area were deposited in the Early Permian, including the Qijiaojing, Julideneng, Shaleisaierke, Yangbulake, Shamaershayi, Liushugou, Qijiagou, and Aoertu formations. The low maturity of the sandstones, zircon morphology and provenance analyses indicate a proximal sedimentation probably sourced from the East ­Junggar Arc and the Harlik-Dananhu Arc in the CNTS. The minor Precambrian detrital zircons are interpreted as recycled materials from the older strata in the Harlik-Dananhu Arc. Zircon ɛ<sub>Hf</sub>(t) values have increased since ~408 Ma, probably reflecting a tectonic transition from regional compression to extension. This event might correspond to the opening of the Bogda intra-arc/back arc rift basin, possibly resulting from a slab rollback during the northward subduction of the North Tianshan Ocean. A decrease of zircon ɛ<sub>Hf</sub>(t) values at ~300 Ma was likely caused by the cessation of oceanic subduction and subsequent collision, which implies that the North Tianshan Ocean closed at the end of the Late Carboniferous. This research was financially supported by the Youth Program of Shaanxi Natural Science Foundation (2020JQ-589), the NSFC Projects (41730213, 42072264, 41902229, 41972237) and Hong Kong RGC GRF (17307918).</p>

Sign in / Sign up

Export Citation Format

Share Document