Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4724037 | Precambrian Research | 2009 | 11 Pages |
Abstract
A biostratigraphic model of the temporal distribution of distinctive Proterozoic microfossil assemblages is suggested, based on studies of upper Precambrian chert-embedded and compression-preserved organic-walled microfossils from the reference sections of Eurasia, North America and Australia. Microfossils from 2.0 to 0.542Â Ga can be divided into seven successive informal global units which can be compared to standard units of the International and Russian time scales. Each unit is characterized by a particular association of taxa, typified by the fossil assemblage that gives it its name. These form broad biostratigraphic units comparable to assemblage zones of Phanerozoic successions; in general (but with minor differences) they correspond to chronostratigraphic units accepted by the Internal Commission on Stratigraphy. The units are: (1) Labradorian, the upper part of the Paleoproterozoic (Orosirian and Statherian), 2.0-1.65Â Ga; (2) Anabarian, lower Mesoproterozoic (Calymmian-Ectasian)/Lower Riphean-lower Middle Riphean, 1.65-1.2Â Ga; (3) Turukhanian, upper Mesoproterozoic (Stenian)/upper Middle Riphean, 1.2-1.03Â Ga; (4) Uchuromayan, lower Neoproterozoic (late Stenian-Tonian)/lower Upper Riphean, 1.03-0.85Â Ga; (5) Yuzhnouralian, upper Neoproterozoic (Cryogenian)/upper Upper Riphean, 0.85-0.63Â Ga; (6) Amadeusian, lower Ediacaran/lower Vendian, 0.63-0.55Â Ga; (7) Belomorian, upper Ediacaran/upper Vendian, 0.55-0.542Â Ga.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geochemistry and Petrology
Authors
V.N. Sergeev,