Actualistic Versus Non-Actualistic Conditions in the Precambrian Sedimentary Record: Reappraisal of an Enduring Discussion

  1. Wladyslaw Altermann3 and
  2. Patricia L. Corcoran4
  1. J. A. Donaldson1,
  2. P. G. Eriksson2 and
  3. W. Altermann3

Published Online: 12 MAR 2009

DOI: 10.1002/9781444304312.ch1

Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems

Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems

How to Cite

Donaldson, J. A., Eriksson, P. G. and Altermann, W. (2002) Actualistic Versus Non-Actualistic Conditions in the Precambrian Sedimentary Record: Reappraisal of an Enduring Discussion, in Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems (eds W. Altermann and P. L. Corcoran), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304312.ch1

Editor Information

  1. 3

    Institut für Allgemeine und Angewandte Geologie, Ludwig-Maximilians-Universität München, Luisenstrasse 37, D-80333 Munich, Germany

  2. 4

    Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 3J5, Canada

Author Information

  1. 1

    Ottawa-Carleton Geoscience Centre, Department of Earth Sciences, Carleton University, Ottawa, ON, K1S 5B6, Canada

  2. 2

    Department of Earth Sciences, University of Pretoria, Pretoria 0002, South Africa

  3. 3

    Institut für Allgemeine und Angewandte Geologie, Ludwig-Maximilians-Universität München, Luisenstrasse 37, D-80333 Munich, Germany

Publication History

  1. Published Online: 12 MAR 2009
  2. Published Print: 18 FEB 2002

ISBN Information

Print ISBN: 9780632064151

Online ISBN: 9781444304312

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Keywords:

  • actualistic versus non-actualistic conditions in precambrian sedimentary record;
  • precambrian sedimentology - actualistic and non-actualistic;
  • actualism and catastrophism;
  • actualistic versus non-actualistic conditions;
  • extreme and unique events and environments in Earth history;
  • precambrian rock record - case for actualism;
  • geological processes and products embraced by actualism

Summary

Actualistic models can be successfully applied to virtually all sedimentary successions preserved in the Precambrian rock record, allowing for differences in the relative rates and intensities of those processes that control weathering, erosion, transportation, deposition and lithification. As the basis for this statement, we understand actualism to be the principle that the same processes and natural laws applied in the past as those active today. This definition readily accommodates events of even catastrophic character, such as bolide impacts and tsunamis. Non-actualistic models introduce semantic problems and are of little help for understanding geological processes. A review of the English and German literature on actualism reveals that many misconceptions can arise because of the two principal meanings of the term ‘actual’: (i) real, factual; (ii) present-day. However, if the full range of possible outcomes subject to natural laws is considered, rather than just the expression of these laws as observed in present environments, all Precambrian settings can be investigated and understood by applying the actualistic approach, which is fundamental but not unique to the geological sciences. Thus, all studies involving Precambrian sedimentary rocks can be approached by means of comparisons to present-day environments. Non-actualistic models should be reserved for speculations about early Hadean environments, cosmology, religion and philosophical conjectures about ‘parallel’ worlds (such as those inhabited by unicorns).