Earth:Parasequence

From HandWiki

A parasequence is a fundamental concept of sequence stratigraphy. Parasequences are not directly related to sequences.

Definition

A parasequence is defined as a genetically related succession of bedsets that is bounded by marine flooding surfaces (or their correlative surfaces) on top and at the bottom.[1] The succession is supposed to be relatively conformable in the sense that breaks in deposition within the parasequence are much shorter than the time of deposition of the parasequence itself.[2][1] Most parasequences show a shallowing upward,[3] which is sometimes also included into the definition.[4]

File:Clastic Parasquences.jpg
Schematic graphic log showing facies successions in common types of clastic parasequences
File:Carbonate Parasequence Architecture.jpg
Schematic graphic log showing facies successions in common types of carbonate parasequences

Properties

Since parasequences are relatively conformable, so Walther's law applies within a parasequence. This is not necessarily the case for transitions from one parasequence to another. They are also typically of the size of one up to tens of meters.[3]

References

  1. 1.0 1.1 Van Wagoner, JC (1988) (in en). An overview of the fundamentals of sequence stratigraphy and key definitions. Special Publications of SEPM. 
  2. Patzkowsky, Mark E.; Holland, Steven M. (2012). Stratigraphic Paleobiology. Chicago: University of Chicago University Press. pp. 34. 
  3. 3.0 3.1 Patzkowsky, Mark E.; Holland, Steven M. (2012). Stratigraphic Paleobiology. Chicago: University of Chicago University Press. pp. 35. 
  4. Catuneanu, Octavian (2011). "Sequence stratigraphy: methodology and nomenclature" (in en). Newsletters on Stratigraphy (E. Schweizerbart'sche Verlagsbuchhandlung) 44 (3): 173–245. doi:10.1127/0078-0421/2011/0011. http://doc.rero.ch/record/28034/files/str_ssm.pdf.