Cyclostratigraphy

The nature of sediments can vary in a cyclic fashion, and these cycles can be displayed in the sedimentary record - here visible in the colouration and resistance of strata

Cyclostratigraphy is the study of astronomically forced climate cycles within sedimentary successions [1]. Astronomical cycles are variations of the Earth's orbit around the sun due to the gravitational interaction with other masses within the solar system. Due to this cyclicity solar irradiation differs through time on different hemispheres and seasonality is affected. These insolation variations have influence on earth's climate and so on the deposition of sedimentary rocks.

The main orbital cycles are precession with at present main periods of 19- and 23-kyr, obliquity with at present main periods of 41-kyr, and 1,2-Myr, and eccentricity with at present main periods of around 100-kyr, 405-kyr, and 2.4-Myr.

Cyclostratigraphic study of rock records can lead to accurate dating of events in the geological past, to increase understanding of cause and consequences of earth's (climate) history, and to more control on depositional mechanisms of sediments and the acting of sedimentary systems.

See also

• Milankovitch cycles
• Stratigraphy

References

• Isabelle Cojan et Maurice Renard, Sédimentologie, 2e éd., Dunod, 2006, ISBN 2100496239 (French)
• Graham P. Weedon, Time-Series Analysis And Cyclostratigraphy: Examining Stratigraphic Records of Environmental Cycles, Cambridge University Press, 2005 ISBN 0521019834 (English)
• André Berger, Le climat de la Terre — Un passé pour quel avenir ?, De Boeck université, 1992, ISBN 2-8041-1497-X (French)
• Brigitte Van Vliet-Lanoë, La planète des glaces — Histoire et environnements de notre ère glaciaire, Vuibert, 2005, ISBN 2711753778 (French)
• Patrick de Wever, Loïc Labrousse, Daniel Raymond, André Schaaf, La mesure du temps dans l'histoire de la Terre, Société géologique de France, édité par Vuibert, 2005, ISBN 271175393X (French)