Stratigraphical characteristics and development of Vendian–Cambrian boundary beds on the East European Platform

Abstract

The present paper serves as a review on the stratigraphy and lithological characteristics of the Cambrian-Vendian boundary beds in the northwestern part of the East European Platform. This transition interval is represented by clastic rocks accumulated in humid climatic conditions. According to the lithological and palaeontological data the corresponding (transition) interval comprises two regional series: the Valdai Regional Series and the Baltic one. They both are divided into two regional stages (from below to top): Redkino, Kotlin, Rovno and Lontova.The Redkino-Kotlin and Kotlin-Rovno boundaries are characterized by distinct contacts reflecting various changes in the sedimentary environment whereas the boundary between the Rovno and Lontova regional stages drawn on the basis of the palaeontological data only falls within the interval of continuous sedimentation.Proceeding from the study of the fossil distribution and their living conditions during late Vendian and early Cambrian on the East European Platform the lower boundary of the Cambrian is most likely situated at the base of the Baltic Series.

Mineralogical and Rb-Sr Isotope Studies of Low-Temperature Diagenesis of Lower Cambrian Clays of the Baltic Paleobasin of north Estonia

“…Ferric iron in these sediments is also observed by the sediment color variations from greenish-gray to occasionally reddish-violet. Red has been interpreted (Mens and Pirrus, 1986) as the "primary" sediment color, and it was preserved owing to the lack of organic material required for iron reduction.…”

“…Thick-bedded, coarse-grained siltstones of the Tiskre Formation occur only in the uppermost part of the section (Mens and Pirrus, 1997a) (Figure 2). Authigenic minerals (glauconite, chemogenic phosphate, pyrite) and fossil assemblages suggest that the sediments were deposited under normal marine conditions (Mens and Pirrus, 1986). Geological data on the wellcharacterized paleogeography and lithology of the Vendian and Cambrian terrigenous sediments on the East-European Platform, including the Baltic Paleobasin, are sunmlarized by Rozanov and Lydka (1987) and Pirrus (1997a, 1997b).…”

A revision of Holm's Early and early Mid Cambrian hyoliths Of Sweden

“…Within Scandinavia these terms may create confusion; when the same terms are used independently outside Scandinavia problems with regard to correlation become evident. In order to avoid confusion we do not italicize fossil names of lithostratigraphical units (see also Mens et al 1987Mens et al , 1990. The oldest term -Hyolithes Zone -was designated by Svenonius (1884) when he divided the stratified rocks of Norrbotten (Lapland).…”

“…Since then several additions, changes and revisions have been made in order to correlate with regions outside Baltoscandia/the East European Platform. We refer to the latest revision of Cambrian zones which was adopted in the IUGS correlations charts (Mens et al 1987(Mens et al , 1990 as the international standard for the above mentioned area. This implies that zone names should not be changed even if generic names are revised, at least not until a new official revision is undertaken.…”

Cambrian (Series 3 – Furongian) conodonts from the Alum Shale Formation at Slemmestad, Oslo Region, Norway

“…A hiatus is developed in central Sweden and the eastern Baltic area that covers the two or three lower trilobite zones of the Acerocarina Superzone (e.g., Martinsson, 1974;Mens & Pirrus, 1977;Szaniawski & Bengtson, 1998). Thus, the horizons with Cordylodus proavus recorded in Estonia and western Russia, the Oslo Region and in Scania, Sweden, are not represented in situ in central Sweden (Szaniawski & Bengtson, 1998;Löfgren & Viira, 2007).…”