Яндекс.Метрика

A.V. Kolesnikov, N.I. Bobkov

Сериальное издание: Estudios Geologicos
Том: 75 , Год издания: 2019

Аннотация

The Asha Group of the South Urals, initially erected by Albert Olli as Palaeozoic sed imentary complex, more than half a century ago was considered as a key section for the Vendian (Ediacaran) of the western slope of the South Urals. However, the ca. 1 700 m-thick terrigenous sedimentary sequence is characterised by unusual low biod iversity of Ediacaran macrofossils, which might be explained by relatively young age of the Asha Group and possible mass extinction event in the end of Ediacaran Period. The relatively young age was confirmed by the U-Pb zircon date of 547.6±3.8 Ma obtained from the tuff in the lower part of the Basa Formation as well as finding of ichnospecies Didymaulichnus tirasensis in the upper part of Zigan formation. However, in 2018 it has been documented there the mass appearing of D. tirasensis in the lowermost part of the Basa Formation. Therefore, the Vendian (Ediacaran) age of the Asha Group of the South U rals can be revisited in favour to terminal EdiacaranCambrian or even early Cambrian.
индекс в базе ИАЦ: 044532