Stratigraphy

As a geological discipline, stratigraphy deals with the spatial location and temporal sequence of rock bodies. By means of stratigraphy, bodies of rock are dated and correlated with each other.

Lower Freshwater Molasse profile (Aquitanian age) in the Wallenried Quarry
Profile of the Lower Freshwater Molasse (Aquitanian age) in the Wallenried Quarry (Canton FR). Deposits of a meandering river in a flood plain.

Summary

The stratigraphic principle

Stratigraphy organizes bodies of rock spatially and chronologically according to their contained characteristics. It places non directly connected rock units together in a relationship (correlation). Stratigraphy is the foundation for the reconstruction of the Earth’s history. It also serves to solve general geological questions.

The stratigraphic principle was formulated in 1669 by Nicolaus Steno in his work Dissertationis prodromus. It is founded on the basis that, with an undisturbed sequence of sedimentary layers, the layer in the footwall (below) is older than the layer in the hanging wall (above). 

Most important sub disciplines

The age determination of rock units, either in years (absolute/numerical age) or as relative age, expressed in in the units of the chronostratigraphic time scale. Chronostratigraphy and geochronology are grouped together in Switzerland.

Age-independent categorization of objectively observable lithological characteristics in the field. Lithostratigraphy provides an as objective as possible reference system for all other stratigraphic studies. The rock units shown in a geological map are lithostratigraphic units.

Relative age determination by means of index fossils.

Categorization of rocks based on the pattern of the sequence of magnetic field reversals.

Categorization of rocks based on sea-level fluctuation influenced sedimentary units (sequences).

Swiss Guidelines

Official Bodies

  • Swiss Committee for Stratigraphy (SKS): The SKS validates the definition and nomenclatural correctness of existing and new lithostratigraphic units in Switzerland; in collaboration with the Swiss Geological Survey it administers the Lithostratigraphic Lexicon of Switzerland
  • International Commission on Stratigraphy (ICS): Defines Global Boundary Stratotype Sections and Points (GSSP) as the basis for the International Stratigraphic Chart.


Fundamentals of Geology

Alain Morard Dr. phil. nat., Geologist
President Swiss Committee on Stratigraphy (SCS)
swisstopo / Swiss Geological Survey
Seftigenstrasse 264
P.O. Box
3084 Wabern
Tel.
+41 58 469 05 49
Fax
+41 58 469 05 45

E-Mail


Print contact

Alain Morard

Dr. phil. nat., Geologist
President Swiss Committee on Stratigraphy (SCS)
swisstopo / Swiss Geological Survey
Seftigenstrasse 264
P.O. Box
3084 Wabern

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