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Episodes 2021; 44(3): 273-283

Published online September 1, 2021


Copyright © International Union of Geological Sciences.

(Re)proposal of three Cambrian Subsystems and their Geochronology

by Ed Landing1*, Gerd Geyer2, Mark D. Schmitz3, Thomas Wotte4, and Artem Kouchinsky5

1 New York State Museum, 222 Madison Avenue, Albany, NY, USA
2 Lehrstuhl für Geodynamik und Geomaterialforschung, Institut für Geographie und Geologie, Bayerische Julius-Maximilians Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
3 Department of Geosciences, Boise State University, 1910 University Drive, Boise, Idaho 83725, USA
4 Department of Palaeontology, TU Bergakademie Freiberg, Bernhard-von-Cotta-Straße, D-09599 Freiberg, Germany
5 Department of Palaeontology, Swedish Museum of Natural History, Box 50007, SE-104 05, Stockholm, Sweden

Correspondence to:*E-mail: ed.landing@nysed.gov

Received: April 29, 2020; Revised: September 24, 2020; Accepted: September 24, 2020

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


The Cambrian is anomalous among geological systems as many reports divide it into three divisions of indeterminate rank. This use of “lower”, “middle”, and “upper” has been a convenient way to subdivide the Cambrian despite agreement it consists of four global series. Traditional divisions of the system into regional series (Lower, Middle, Upper) reflected local biotic developments not interprovincially correlatable with any precision. However, use of “lower”, “middle”, and “upper” is unsatisfactory. These adjectives lack standard definition, evoke the regional series, and are misused. Notably, there is an almost 50 year use of three Cambrian subsystems and a 1997 proposal to divide the Avalonian and global Cambrian into four series and three subsystems. The global series allow proposal of three formal subsystems: a ca. 32.6 Ma Lower Cambrian Subsystem (Terreneuvian and Series 2/proposed Lenaldanian Series), a ca. 9.8 Ma Middle, and a ca. 10 Ma Upper Cambrian Subsystem (=Furongian Series). Designations as “Lower Cambrian Subsystem” or “global Lower Cambrian” distinguish the new units from such earlier units as “Lower Cambrian Series” and substitute for the de facto subsystem terms “lower”, “middle”, and “upper”. Cambrian subsystems are comparable to the Carboniferous’ Lower (Mississippian) and Upper (Pennsylvanian) Subsystems.