| 1. |
- Li, Z. X., et al.
(författare)
-
How not to build a supercontinent: A reply to JDA Piper
- 2009
-
Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 174:1-2, s. 208-214
-
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.
|
|
| 2. |
|
|
| 3. |
- Gladkochub, D. P., et al.
(författare)
-
1.79–1.75 Ga mafic magmatism of the Siberian craton and late Paleoproterozoic paleogeography
- 2022
-
Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 370
-
Tidskriftsartikel (refereegranskat)abstract
- The paper presents new geological, geochronological, geochemical, and Nd isotopic data on the late Paleoproterozoic dolerites of the Siberian craton. U-Pb baddeleyite ages of the Doros dolerites (Aldan shield, south-eastern Siberia) and East Anabar dolerites (Anabar shield, northern Siberia) are 1757 ± 4 and 1774 ± 6 Ma, respectively. This new geochronological data together with published 1.76–1.75 Ga ages for Timpton-Algamay dolerites of the Aldan shield and Chaya dolerites of the Baikal uplift (southern Siberia) revealed a 20 my difference between this magmatism in the north and south Siberia. The Doros dolerites in their chemical compositions correspond to sub-alkaline basaltic andesites, but the East Anabar dolerite is chemically close to basaltic trachyandesite. The Doros dolerites demonstrate negative and close to zero ɛNd(t) values (from −7.0 to +0.1), which correlate well with SiO2 and Mg#. All Doros dolerites have Nb–Ta and Ti anomalies in multielement spectra. The geochemical and Nd isotopic data suggest that the Doros dolerites have been formed by the mixing of mantle and crustal material. The East Anabar dolerites are characterized by a negative ɛNd(t) value of −3.7, negative Nb–Ta anomaly in multielement spectra, high concentrations of TiO2 and P2O5. The 1775 Ma East Anabar dolerites could be generated from a subcontinental lithospheric mantle source, possibly with some mantle plume interaction (possibly centred at the convergence with the 1.76–1.75 Ga fanning Aldan swarm). Geochemistry and Nd isotope systematics of all 1.78–1.75 Ga mafic dykes and intrusions of the Siberian craton indicate the subcontinental lithospheric mantle source or mantle source contaminated by crustal material. Geochronological data from the 1.79–1.75 Ga magmatic rocks of Siberia and other continents suggest continuous magmatism over this interval in some continents, but a series of short magmatic events/pulses (from one to four) separated by intervals of quiescence in other continents. We locate the analysed dykes and sills on new 1750 Ma and 1790 Ma global paleogeographic reconstructions. Analysis of 1.79–1.75 Ga geochemical data on mafic intrusions from Late Paleoproterozoic continents suggests the prevalence of subcontinental lithospheric mantle source for the mafic intrusions over the pure mantle plume source.
|
|
| 4. |
|
|
| 5. |
- Ernst, R. E., et al.
(författare)
-
Identification of the ca. 720 Ma Irkutsk LIP and its plume centre in southern Siberia : The initiation of Laurentia-Siberia separation
- 2023
-
Ingår i: Precambrian Research. - 0301-9268. ; 394
-
Tidskriftsartikel (refereegranskat)abstract
- Widespread 720 Ma magmatism has been linked with the break-up of Rodinia and the onset of the Sturtian ‘Snowball Earth’ event. We report a new U-Pb baddeleyite age from the Baikal dyke subswarm in southern Siberia which increases the known extent of the 720 Ma Irkutsk LIP and confirms a previous hypothesis that the Baikal and Sayan subswarms converge at the southern tip of the Irkutsk promontory. Together they define a mantle plume centre with direct links to the 720 Ma Franklin plume centre of northern Laurentia, thus constraining the paleo-reconstruction of southern Siberia and northern Laurentia. It is inferred that this combined 720 Franklin – Irktusk LIP event is associated with the breakup of southern Siberia from northern Laurentia during fragmentation of the Rodinia supercontinent. Expansion of 720 Ma magmatism into Siberia greatly increases the scale of the Franklin-Irktusk LIP.
|
|
| 6. |
|
|
| 7. |
- Gladkochub, D. P., et al.
(författare)
-
Proterozoic basic magmatism of the Siberian Craton: Main stages and their geodynamic interpretation
- 2012
-
Ingår i: Geotectonics. - 0016-8521. ; 46:4, s. 273-284
-
Tidskriftsartikel (refereegranskat)abstract
- Geological data on the Precambrian basic complexes of the Siberian Craton and their isotopic age are considered. The three main episodes of Precambrian basic magmatism of Siberia correspond to certain stages of the geodynamic evolution of the craton and the Earth as a whole. In the Late Paleoproterozoic, largely in the south and the north of the craton, the basic rocks were emplaced against the background of post-collision extension, which followed the preceding collision-accretion stage responsible for the formation of the craton. In the Mesoproterozoic, primarily in the north of the craton, basic magmatism was controlled by dispersed within-plate extension apparently caused by the impact of a mantle plume. Neoproterozoic basic magmatism widespread in the southern and southeastern parts of the craton was caused by rifting, which accompanied breakdown of the Rodinia supercontinent and opening of the Paleoasian ocean along the southern margin of the Siberian Craton.
|
|
| 8. |
- Lubnina, Natalia V., et al.
(författare)
-
Fennoscandia before Nuna/Columbia : Paleomagnetism of 1.98–1.96 Ga mafic rocks of the Karelian craton and paleogeographic implications
- 2017
-
Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 292, s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- Numerous mafic dykes, sills and intrusions with ages between 1985 Ma and 1960 Ma are exposed near the Onega Lake in southern Karelia, Russia. The paleomagnetic analysis of these rocks has revealed a stable remanence with directions belonging to two groups. The directions of the first group characterize ten intrusions including the dated 1970 ± 3 Ma Unoi sill and 1976 ± 9 Ma Suna River Canyon dolerite, the corresponding paleomagnetic pole is 44.4°N, 101.5°E, A95 = 6.3°. The second group comprises two intrusions including the 1984 ± 8 Ma Pudozhgora intrusion and Krestoviy Navolok dyke with the corresponding paleopole calculated from 5 site mean poles is 60.9°N, 144.8°E, A95 = 6.8°. Both remanence directions are supported by robust baked contact tests. We propose the first group's pole as the key 1975 Ma Fennoscandian pole. The second one is well dated, but based only on two intrusions without proper averaging of the paleosecular variations. We have also carried out a complimentary paleomagnetic study of the previously investigated 2504 Ma Shalskiy gabbronorite dyke. The remanence of this dyke is now supported by the inverse contact test and statistics can be improved. Using our 1975 Ma pole together with coeval poles from Superior, Slave and Amazonia cratons we propose a provisional 1975 Ma paleogeographic reconstruction.
|
|
| 9. |
- Bogdanova, Svetlana, et al.
(författare)
-
Assembly and Breakup of Rodinia (Some results of IGCP project 440)
- 2009
-
Ingår i: Stratigraphy and Geological Correlation. - 0869-5938. ; 17:3, s. 259-274
-
Forskningsöversikt (refereegranskat)abstract
- The principal results of project 440 "Assembly and Breakup of Rodinia" of the International Geological Correlation Programme (IGCP) are reviewed in this work. A map of that supercontinent compiled using geological and paleomagnetic data describes global paleogeography 900 Ma ago. The assembly of Rodinia, which comprised most of Precambrian continental blocks, lasted ca. 400 m.y. (from 1300 to 900 Ma). Its breakup presumably triggered by mantle superplume took place between 830 and 650 Ma. The correlation between tectonic events in different continental blocks is considered. Some problems concerning the Rodinia reconstruction and history, e.g., the slow growth of juvenile crust and effects of mantle-plume events during the amalgamation period and of glaciations at the breakup time, are discussed. The latter caused changes in the biosphere and climate, whereas postglacial periods stimulated progress in biota evolution.
|
|
| 10. |
- Pisarevsky, S A, et al.
(författare)
-
Palaeomagnetism of 935 Ma mafic dykes in southern Sweden and implications for the Sveconorwegian Loop
- 2006
-
Ingår i: Geophysical Journal International. - 0956-540X. ; 166:3, s. 1095-1104
-
Tidskriftsartikel (refereegranskat)abstract
- New palaeomagnetic results for the 935 Ma Goteborg-Slussen mafic dykes in southern Sweden provide a well-dated high-quality palaeomagnetic pole for Early Neoproterozoic Baltica. New U-Pb geochronological data for several palaeomagnetically studied mafic intrusions yield three additional well-dated palaeopoles and one virtual geomagnetic pole. This set of dated poles suggests minimal drift of Baltica in moderate latitudes between similar to 965 and 915 Ma. They also support the hypothesis of a post-900 Ma regional remagnetization event in SW Sweden and SW Norway. The positions of three distinct clusters of similar to 1100 to 850 Ma palaeopoles suggest a clockwise time progression of the Baltica apparent polar wander path (the Sveconorwegian Loop) during this time interval. New well-dated palaeomagnetic poles for similar to 970 to 900 Ma from Laurentia are required to verify the palaeogeographic reconstructions of Baltica and Laurentia.
|
|
