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| Titel |
Middle Paleozoic-Mesozoic boundary of the North Asian craton and the Okhotsk terrane: new geochemical and geochronological data and their geodynamic interpretation |
| VerfasserIn |
A. V. Prokopiev, J. Toro, J. K. Hourigan, A. G. Bakharev, E. L. Miller |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1868-4556
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| Digitales Dokument |
URL |
| Erschienen |
In: Geology, geophysics and tectonics of Northeastern Russia: a tribute to Leonid Parfenov ; Nr. 4 (2009-09-17), S.71-84 |
| Datensatznummer |
250001440
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| Publikation (Nr.) |
 copernicus.org/smsps-4-71-2009.pdf |
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| Zusammenfassung |
The Okhotsk terrane, located east of the South Verkhoyansk sector of
the Verkhoyansk fold-and-thrust belt, has Archean crystalline
basement and Riphean to Early Paleozoic sedimentary cover similar to
that of the adjacent the North Asian craton. However, 2.6 Ga
biotite orthogneisses of the Upper Maya uplift of the Okhotsk
terrane yielded Early Devonian 40Ar/39Ar cooling ages,
evidence of a Mid-Paleozoic metamorphic event not previously known.
These gneisses are also intruded by 375±2 Ma (Late Devonian)
calc-alkaline granodiorite plutons that we interpret as part of a
continental margin volcanic arc. Therefore, Late Devonian rifting,
which affected the entire eastern margin of North Asia separating
the Okhotsk terrane from the North Asian craton, was probably a
back-arc event.
Our limited 40Ar/39Ar data from the South Verkhoyansk metamorphic
belt suggests that low grade metamorphism and deformation started in the
Late Jurassic due to accretion of the Okhotsk terrane to the North Asia
margin along the Bilyakchan fault. Shortening and ductile strain continued
in the core of the South Verkhoyansk metamorphic belt until about 120 Ma due
to paleo-Pacific subduction along the Uda-Murgal continental margin arc. |
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