Precambrain time units and nomenclature - the geon concept
- Univ. of Montreal, Quebec (Canada)
The International Commission on Stratigraphy (ICS) recently published its first edition of the Global Stratigraphic Chart. The chart includes, among other, 12 new terms for divisions of the Proterozoic that were approved by the Subcommission on Precambrain Stratigraphy. The Proterozoic is divided into three eras at 1600 and 1000 Ma, and the units are named Paleoproterozoic, Mesoproterozoic, and Neoproterozoic. If the primary goal of the Subcommission on Precambrian Stratigraphy was the division of the Proterozoic into broad time units, as can be surmised by statements in earlier proposals, then one wonders about the value of a complex nomenclature for divisions whose boundaries are defined at round 200 m.y. intervals without reference to standard sections. A geologic calendar using the concept of geon (a time unit of 10{sup 8} a) is suggested an alternative to the recently proposed complex nomenclature for Proterozoic periods.
- OSTI ID:
- 6213125
- Journal Information:
- Geology; (USA), Vol. 18:4; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
Similar Records
Sequence stratigraphy - historical perspective of concepts, problems, and challenges in exploration
Tectonics of Precambrian basement along the Pacific margin of Antarctica and relation to western North America