Okuzeka
Geology & Earth Sciences vocabulary · Geologic Time & Fossils

Law of superposition

Meaning in geology & earth sciences, with examples

nounCommon term

In geology & earth sciences, law of superposition means: The principle that in undisturbed layers of sedimentary rock, the oldest layer is at the bottom and each layer above it is younger.

In Turkish: üst üste gelme ilkesi, süperpozisyon ilkesi, tabakaların üst üste gelme yasası

How it is used

One of the basic principles of relative dating, first described by Nicolas Steno in the 17th century. Geologists apply it with care, because folding and faulting can turn layers upside down. Also called the principle of superposition.

Example sentences

  1. By the law of superposition, the sandstone at the base of the cliff is the oldest unit.

  2. Fossils showed that the law of superposition could not be applied here, because the strata were overturned.

Common collocations

  • the law of superposition
  • apply the law of superposition
  • principle of superposition
  • relative dating
  • stratumA single layer of sedimentary rock or sediment with similar features throughout, separated from the layers above and below it. The plural is strata.
  • unconformityA surface between rock layers that marks a gap in the geological record, where erosion removed rock or no sediment was deposited for a long time.
  • fossilThe remains or traces of a plant or animal that lived long ago, preserved in rock, such as shells, bones, leaf impressions or footprints.
  • geologic time scaleThe system that divides the Earth's roughly 4.6-billion-year history into named units such as eons, eras, periods and epochs, based on rocks and fossils.

More terms: Geologic Time & Fossils

Practise with graded reading

Reading at the right level is the fastest way to make new words stick. Pick free English books by level: