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| Titel |
Provenance analysis and tectonic setting of the Triassic clastic deposits in Western Chukotka, Northeast Russia |
| VerfasserIn |
M. I. Tuchkova, S. Sokolov, I. R. Kravchenko-Berezhnoy |
| 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.177-200 |
| Datensatznummer |
250001447
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| Publikation (Nr.) |
 copernicus.org/smsps-4-177-2009.pdf |
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| Zusammenfassung |
| The study area is part of the Anyui subterrane of the Chukotka microplate, a
key element in the evolution of the Amerasia Basin, located in Western
Chukotka, Northeast Russia. The subterrane contains variably deformed, folded
and cleaved rhythmic Triassic terrigenous deposits which represent the
youngest stage of widespread marine deposition which form three different
complexes: Lower-Middle Triassic, Upper Triassic (Carnian) and Upper Triassic
(Norian). All of the complexes are represented by rhythmic interbeds of
sandstone, siltstone and mudstone. Macrofaunas are not numerous, and in some
cases deposits are dated by analogy to, or by their relationship with, other
units dated with macrofaunas. The deposits are composed of pelagic sediments,
low-density flows, high-density flows, and shelf facies associations
suggesting that sedimentation was controlled by deltaic progradation on a
continental shelf and subsequent submarine fan sedimentation at the base of
the continental slope. Petrographic study of the mineral composition
indicates that the sandstones are lithic arenites. Although the Triassic
sandstones appear similar in outcrop and by classification, the constituent
rock fragments are of diverse lithologies, and change in composition from
lower grade metamorphic rocks in the Lower-Middle Triassic to higher grade
metamorphic rocks in the Upper Triassic. This change suggests that the
Triassic deposits represent an unroofing sequence as the source of the
clastic material came from more deeply buried rocks with time. |
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