NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Learning to tell Neoproterozoic timeIn 1989, the International Commission on Stratigraphy established a Working Group on the Terminal Proterozoic Period. Nine years of intensive, multidisciplinary research by scientists from some two dozen countries have markedly improved the framework for the correlation and calibration of latest Proterozoic events. Three principal phenomena--the Marinoan ice age, Ediacaran animal diversification, and the beginning of the Cambrian Period--specify the limits and character of this interval, but chemostratigraphy and biostratigraphy based on single-celled microfossils (acritarchs), integrated with high-resolution radiometric dates, provide the temporal framework necessary to order and evaluate terminal Proterozoic tectonic, biogeochemical, climatic, and biological events. These data also provide a rational basis for choosing the Global Stratotype Section and Point (GSSP) that will define the beginning of this period. A comparable level of stratigraphic resolution may be achievable for the preceding Cryogenian Period, providing an opportunity to define this interval, as well, in chronostratigraphic terms--perhaps bounded at beginning and end by the onset of Sturtian glaciation and the decay of Marinoan ice sheets, respectively. Limited paleontological, isotopic, and radiometric data additionally suggest a real but more distant prospect of lower Neoproterozoic correlation and stratigraphic subdivision.
Document ID
20040088902
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Knoll, A. H.
(Botanical Museum, Harvard University Cambridge, MA 02138, United States)
Date Acquired
August 21, 2013
Publication Date
March 1, 2000
Publication Information
Publication: Precambrian research
Volume: 100
Issue: 3-Jan
ISSN: 0301-9268
Subject Category
Geosciences (General)
Funding Number(s)
CONTRACT_GRANT: NCC2-1053
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
Non-NASA Center
Review, Academic
Review

Available Downloads

There are no available downloads for this record.
No Preview Available