Autor: John I. Garver, M. I. Tuchkova, I. I. Podgornyi, G. E. Bondarenko, A. V. Soloviev
Rok vydání: 2003
Předmět:
Zdroj: Lithology and Mineral Resources. 38:162-176
ISSN: 0024-4902
DOI: 10.1023/a:1023456126348
Popis: The South Anyui fold zone (western Chukotka) is considered a suture zone related to closure of the South Anyui oceanic basin and collision of Eurasia with the Chukotka-Arctic Alaska microcontinent in the Early Cretaceous. The existence of a compensatory sedimentation basin (foredeep) during folding in the termi- nal Jurassic-initial Cretaceous remains debatable. This work presents first data on age estimates of detrital zir- cons from Upper Mesozoic terrigenous sequences of the South Anyui suture zone obtained by the fission-track method. The distal flysch of presumably Late Jurassic age and the proximal flysch of probably Late Triassic age were sampled in the Uyamkanda River basin. The fission-track dating showed that sandstones from the flysch sections contain detrital zircons of two different-age populations. Young zircon populations from sandstones of distal turbidites in the upper course of the Uyamkanda River (two samples) are 149 ± 10.2 and 155.4 ± 9.0 Ma old (Late Jurassic), whereas those from coarse-grained proximal turbidites sampled in the lower course of the Uyamkanda River (one sample) is 131.1 ± 7.5 Ma old (Early Cretaceous). The data obtained indicate that the Late Mesozoic folding in the South Anyui suture zone was accompanied by the formation of a marginal sedi- mentary basin. Sediments accumulated in this basin compose tectonic nappes that constitute a fold-thrust struc- ture with the northern vergence.
Databáze: OpenAIRE
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