Book contents
- Frontmatter
- Contents
- List of Contributors
- Preface
- The Proterozoic Biosphere
- PART I
- 1 Geology and Paleobiology of the Archean Earth
- 2 Geological Evolution of the Proterozoic Earth
- 3 Proterozoic Biogeochemistry
- 4 Proterozoic Atmosphere and Ocean
- 5 Proterozoic and Selected Early Cambrian Microfossils: Prokaryotes and Protists
- 6 Modern Mat-Building Microbial Communities: a Key to the Interpretation of Proterozoic Stromatolitic Communities
- 7 Proterozoic and Earliest Cambrian Carbonaceous Remains, Trace and Body Fossils
- 8 The Proterozoic-Early Cambrian Evolution of Metaphytes and Metazoans
- 9 Molecular Phylogenetics, Molecular Paleontology, and the Proterozoic Fossil Record
- 10 Biostratigraphy and Paleobiogeography of the Proterozoic
- 11 Biotic Diversity and Rates of Evolution During Proterozoic and Earliest Phanerozoic Time
- 12 A Paleogeographic Model for Vendian and Cambrian Time
- 13 Evolution of the Proterozoic Biosphere: Benchmarks, Tempo, and Mode
- PART 2
- References Cited
- Subject Index
- Index to Geologic Units
- Taxonomic Index
2 - Geological Evolution of the Proterozoic Earth
Published online by Cambridge University Press: 04 April 2011
- Frontmatter
- Contents
- List of Contributors
- Preface
- The Proterozoic Biosphere
- PART I
- 1 Geology and Paleobiology of the Archean Earth
- 2 Geological Evolution of the Proterozoic Earth
- 3 Proterozoic Biogeochemistry
- 4 Proterozoic Atmosphere and Ocean
- 5 Proterozoic and Selected Early Cambrian Microfossils: Prokaryotes and Protists
- 6 Modern Mat-Building Microbial Communities: a Key to the Interpretation of Proterozoic Stromatolitic Communities
- 7 Proterozoic and Earliest Cambrian Carbonaceous Remains, Trace and Body Fossils
- 8 The Proterozoic-Early Cambrian Evolution of Metaphytes and Metazoans
- 9 Molecular Phylogenetics, Molecular Paleontology, and the Proterozoic Fossil Record
- 10 Biostratigraphy and Paleobiogeography of the Proterozoic
- 11 Biotic Diversity and Rates of Evolution During Proterozoic and Earliest Phanerozoic Time
- 12 A Paleogeographic Model for Vendian and Cambrian Time
- 13 Evolution of the Proterozoic Biosphere: Benchmarks, Tempo, and Mode
- PART 2
- References Cited
- Subject Index
- Index to Geologic Units
- Taxonomic Index
Summary
The Proterozoic Eon extends from 2500 to 550 Ma, from the close of the Archean to the beginning of the Cambrian. It includes three principal geochronologic divisions: Lower or Proterozoic I (2500 to 1600 Ma), Middle or Proterozoic II (1600 to 900 Ma), and Upper or Proterozoic III (900 to 550 Ma). These definitions are consistent with previous usage (Schopf 1983a) and with recommendations of the Subcommission on Precambrian Stratigraphy of the International Union of Geological Sciences (Plumb and James 1986). Although some criticism has been voiced at the use of absolute ages rather than stratigraphic or paleontologic events for subdividing Precambrian time (Cloud 1987), we find that the lack of well-developed, widespread, narrowly constrained, isochronous Precambrian biostratigraphic markers, equivalent to Phanerozoic faunal successions, presents an as yet insurmountable barrier to the establishment of globally useful Precambrian biostratigraphic subdivisions.
Systematic treatment of the geological evolution of the Proterozoic earth and similar long-term or large-scale aspects of Proterozoic history is complicated at present by our incomplete knowledge of existing Proterozoic rocks, selective preservation/obliteration of certain types of terranes, and uncertain geochronology and correlation. Many Proterozoic sequences remain essentially unstudied, especially in parts of central and northern Africa, South America, and Asia, and their stratigraphies, ages, and tectonic settings are unresolved. Information from these sequences is essential to evaluation of global patterns of Proterozoic geologic evolution, sediment recycling, and tectonics.
- Type
- Chapter
- Information
- The Proterozoic BiosphereA Multidisciplinary Study, pp. 43 - 80Publisher: Cambridge University PressPrint publication year: 1992
- 1
- Cited by