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| 2. |
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| 3. |
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| 4. |
- Abbafati, Cristiana, et al.
(författare)
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- 2020
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Vernikovskaya, A.E., Pease, V.L., Vernikovsky, V.A., Gee, D.G. & Travin, A.V.
(författare)
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Geochemistry and Petrology of Neoproterozoic Granites of the Mamont-Shrenk Terrane, Central Taimyr
- 2002
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Ingår i: Geochemical International. ; 40, s. 435-446
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Li, Z. X., et al.
(författare)
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How not to build a supercontinent: A reply to JDA Piper
- 2009
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Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 174:1-2, s. 208-214
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The hypothesized existence of a Neoproterozoic supercontinent called Rodinia is based on a series of geological and paleomagnetic observations, with details about the configuration and evolution of this supercontinent still a matter for debate. Regrettably, we found that the comment by Piper (this volume) lacks scientific objectiveness. The 'Palaeopangaea' that he promotes is, in our view, based on incorrect application of paleomagnetic data, and is not supported by geological evidence. (C) 2009 Elsevier B.V. All rights reserved.
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| 7. |
- Luchitskaya, M. V., et al.
(författare)
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Composition, Age, and Origin of Cretaceous Granitic Magmatism on the Eastern Chukchi Peninsula
- 2018
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Ingår i: Geotectonics. - 0016-8521 .- 1556-1976. ; 52:3, s. 312-330
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Tidskriftsartikel (refereegranskat)abstract
- New geochronological and isotopic geochemical data are given, which make it possible to recognize two types of granitic rocks on the eastern Chukchi Peninsula. Early Cretaceous Tkachen and Dolina granitic plutons with zircon ages (U-Pb SIMS) of 119-122 and 131-136 Ma are related to the first type. They cut through Devonian-Lower Carboniferous basement rocks and are overlain by the Aptian-Albian Etelkuyum Formation. Basal units of the latter contain fragments of granitic rocks. Late Cretaceous Provideniya and Rumilet granitic plutons, which contain zircons with ages of 94 and 85 Ma (U-Pb SIMS), respectively, belong to the second type. They cut through volcanic-sedimentary rocks of the Etelkuyum and Leurvaam formations pertaining to the Okhotsk-Chukotka Volcanic Belt. In petrographic and geochemical features, the Early Cretaceous granitic rocks of the Tkachen Pluton are commensurable with I-type granites, while Late Cretaceous granite of the Rumilet Pluton is comparable to A(2)-type granite. The Sr-Nd isotopic data provide evidence that from the Early Cretaceous Tkachen and Dolina plutons to the Late Cretaceous Provideniya and Rumilet plutons, the degree of crustal assimilation of suprasubduction mantle-derived melts increases up to partial melting of heterogeneous continental crust enriched in rubidium. An unconformity and various degrees of secondary alteration of volcanic-sedimentary rocks have been established in the Okhotsk-Chukotka Volcanic Belt, and this was apparently caused by transition of the tectonic setting from suprasubduction to a transform margin with local extension.
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| 8. |
- Pease, v., Gee, D.G., Vernikovsky, V.A., Vernikovskaya, A. and Kireev, S.
(författare)
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The Mamont-Shrenk terrane: A Mesoprpterozoic complex in the Neoproterozoic accretionary belt of central Taimyr, northern Siberia
- 2001
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Ingår i: Terra Nova. ; :13, s. 270-280
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Tidskriftsartikel (refereegranskat)
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Gottlieb, Erik S., et al.
(författare)
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Neoproterozoic basement history of Wrangel Island and Arctic Chukotka : integrated insights from zircon U–Pb, O and Hf isotopic studies
- 2018
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Ingår i: Geological Society Special Publication. - 0305-8719 .- 2041-4927. ; 460:1
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Tidskriftsartikel (refereegranskat)abstract
- The pre-Cenozoic kinematic and tectonic history of the Arctic Alaska Chukotka (AAC) terrane is not well known. The difficulties in assessing the history of the AAC terrane are predominantly due to a lack of comprehensive knowledge about the composition and age of its basement. During the Mesozoic, the AAC terrane was involved in crustal shortening, followed by magmatism and extension with localized high-grade metamorphism and partial melting, all of which obscured its pre-orogenic geological relationships. New zircon geochronology and isotope geochemistry results from Wrangel Island and western Chukotka basement rocks establish and strengthen intra- and inter-terrane lithological and tectonic correlations of the AAC terrane. Zircon U–Pb ages of five granitic and one volcanic sample from greenschist facies rocks on Wrangel Island range between 620±6 and 711±4 Ma, whereas two samples from the migmatitic basement of the Velitkenay massif near the Arctic coast of Chukotka yield 612±7 and 661±11 Ma ages. The age spectrum (0.95–2.0 Ga with a peak at 1.1 Ga and minor 2.5–2.7 Ga) and trace element geochemistry of inherited detrital zircons in a 703±5 Ma granodiorite on Wrangel Island suggests a Grenville–Sveconorwegian provenance for metasedimentary strata in the Wrangel Complex basement and correlates with the detrital zircon spectra of strata from Arctic Alaska and Pearya. Temporal patterns of zircon inheritance and O–Hf isotopes are consistent with Cryogenian–Ediacaran AAC magmatism in a peripheral/external orogenic setting (i.e. a fringing arc on rifted continental margin crust).
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| 15. |
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| 16. |
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| 17. |
- Ledneva, G. V., et al.
(författare)
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Late Triassic siliceous-volcano-terrigenous deposits of the Chukchi Peninsula : composition of igneous rocks, U-Pb age of zircons, and geodynamic interpretations
- 2016
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Ingår i: Russian Geology and Geophysics. - : GeoScienceWorld. - 1068-7971 .- 1878-030X. ; 57:8, s. 1119-1134
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Tidskriftsartikel (refereegranskat)abstract
- Study of Late Triassic volcanic, subvolcanic, and volcanosedimentary rocks of the Chukchi Peninsula (Vel'may terrane) has shown their different geochemical types. Basalts, dolerites, and tuffs of the lower-middle strata of the Upper Triassic section bear evidence for their formation in suprasubductional geodynamic setting. Basalts and dolerites of the upper strata of this section correspond in composition to within-plate rocks and are similar to Middle-Late Triassic oceanic-plateau basalts and dolerites. U-Pb dating of magmatic zircons from tuffs of the lower-middle strata and from dolerites of the upper strata shows the almost synchronous magmatic activity in the suprasubductional (206 +/- 5 Ma) and within-plate (212 +/- 4 Ma) geodynamic settings. (C) 2016, V.S. Sobolev IGM, Siberian Branch of the RAS.
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| 18. |
- Ledneva, Galina V., et al.
(författare)
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Permo"Triassic hypabyssal mafic intrusions and associated tholeiitic basalts of the Kolyuchinskaya Bay, Chukotka (NE Russia) : Links to the Siberian LIP
- 2011
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Ingår i: Journal of Asian Earth Sciences. - : Elsevier BV. - 1367-9120 .- 1878-5786. ; 40:3, s. 737-745
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Tidskriftsartikel (refereegranskat)abstract
- In order to test tectonic hypotheses regarding the evolution of the Arctic Alaska-Chukotka microplate prior to the opening of the Amerasian basin, we investigated rocks exposed near Kolyuchinskaya Bay, eastern Chukotka. Hypabyssal mafic rocks and associated basaltic flows enclose terrigenous sediments, minor cherts and limestones in pillow interstices. The hypabyssal mafic rock yields a U-Pb zircon age of 252 +/- 4 Ma and indicates intrusion of basic magma at the Permo-Triassic boundary, contemporaneous with voluminous magmatism of the Siberian large igneous province (LIP). The lava flows and hypabyssal mafic rocks of the Kolyuchinskaya Bay region have trace elements, Sm-Nd and Rb-Sr isotope compositions identical to the tholeiitic flood basalts of the main plateau stage of the Siberian LIP, but differ from the latter in the major-element variations. We conclude that compositional variations in the hypabyssal rocks studied reflect their generation in an extensional environment that might be related to the Siberian super-plume activity at the time. Although the genetic and temporal links between intrusive mafic rocks and lavas are not well proved, compositional variations of the eruptive rocks still indicate their generation in an extensional environment.
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| 19. |
- Pease, Victoria, et al.
(författare)
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Baltica in the Cryogenian, 850-650 Ma
- 2008
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Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 160:1-2, s. 46-65
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Forskningsöversikt (refereegranskat)abstract
- This new tectonic synthesis provides a framework for understanding the dynamic evolution of Baltica and for constraining tectonic correlations within the context of the Neoproterozoic break-up of Rodinia–Pannotia. Cryogenian Baltica is described with respect to five geographic regions: the northwest, northeast, east, south, and southwest (modern coordinates). These geographic regions define three principal Cryogenian tectonic margins: a rifting northwestern margin, a passive northeastern margin, and a poorly understood southern margin. The northwest region is characterized by Neoproterozoic to lower Ordovician sedimentary successions deposited on Archean to late Mesoproterozoic crystalline complexes, reworked during Caledonian orogenesis. Lare Neoproterozoic to lower Ordovician sedimentary strata record the change from an alluvial setting to a marine environment, and eventually to a partially starved (?) turbidite basin. They document rifting from the Rodinian-Pannotian supercontinent, which was unsuccessful until ca. 620–550 Ma when voluminous dikes and mafic/ultramafic complexes were intruded. Baltica's northeastern and eastern regions document episodic intracratonic rifting throughout the Mesoproterozoic, followed by pericontinental passive margin deposition throughout the Cryogenian. In the northeast platformal and deeper-water basin deposits are preserved, whereas the eastern region was later affected by Paleozoic rifting and preserves only shelf deposits. The northeastern and eastern regions define Baltica's Cryogenian northeastern tectonic margin, which was an ocean-facing passive margin of the Rodinia–Pannotia supercontinent. It remained a passive margin until the onset of Timanian orogenesis at ca. 615 Ma, approximately synchronous with the time of Rodinia–Pannotia rifting. Baltica's southern and southwestern regions remain enigmatic and controversial. Precambrian basement is generally hidden beneath thick successions of Ediacaran and younger platform sediments. Similarities between these regions exist, however, and suggest that they may share a similar tectonic evolution in the Cryogenian and therefore define the southern tectonic margin of Baltica at this time. Paleo- to Mesoproterozic basement was affected by Neoproterozoic and younger tectonism, including Cryogenian (?) and Ediacaran rifting. This was followed by Ediacaran (ca. 550 Ma) passive margin sediment deposition at the time of Rodinia–Pannotia break-up, until Early Paleozoic accretion of allochthonous terranes record the transition from rifting to a compressional regime. Paleomagnetic and paleontological data are consistent with Baltica and Laurentia drifting together between ca. 750 and 550 Ma, when they had similar apparent polar wander paths. Microfossil assemblages along the eastern margin of Laurentia and the western margin of Baltica (modern coordinates), suggest proximity between these two margins at this time. At ca. 550 Ma, Laurentia and Baltica separated, consistent with paleomagnetic, paleontological, and geological data, and a late break-up for Rodinia–Pannotia.
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Pease, V, et al.
(författare)
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The JEBEL Project
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 25. |
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