Walther’sWalther’s law of correlation of facieslaw of correlation of facies

The principle that facies that occur in conformable vertical successions of strata also occur in laterally adjacent environments.[A vertical progression of facies can be found corresponding lateral facies changes]

Walther’sWalther’s PrinciplePrinciple< vertical and horizontal facies match >

The various deposits of the same facies-area and similarly the sum of the rocks of different facies-areas are formed beside each other in space, though in a cross section we see them lying on top of each other.As with biotypes, it is a basic statement of far reaching significance that only those facies and facies-areas can be superimposed primarily which can be observed beside each other at the present time.

Walther’sWalther’s LawLaw• Sedimentary rock types record the environment

of their deposition.• Depositional environments can shift laterally as

conditions change.• When so, laterally related environments become

superimposed.• Time-transgressive sedimentary formations, are

the result.• The vertical succession and lateral sequence of

facies will be the same.

Walther’sWalther’s LawLaw• Certain facies associations are common in the

rock record.• For example, most clastic shoreline show a

series of depositional environments that are progressively finer-grained in the offshore direction.

• There are facies belts of coarses sands, and silts and clays. If the relative sea level changes, deposits of these facies belts accumulate.

• Three facies pattern are possible.

Walther’sWalther’s LawLawFacies belts could pile up vertically if the

relative rate of sea-level rise is exactly balanced by the sedimentary output of the land.

Walther’sWalther’s LawLawFacies show a transgressive pattern when the

sediment supply is overpower by a relative rise in sea level, or when the land subsides tectonically. Both cause the shoreline to move landward

Walther’sWalther’s LawLaw Facies show a regression pattern when the

shoreline moves seaward due to an excess sediment supply from land, when the land is tectonically uplifted and the sea level retreats, or when there is a relative lowering of sea level.

Walther’s Law Exceptions

• The law is invalid where the contact between

different lithologies is non-conformable (due

to lack of deposition), or during cases of rapid

environmental change when non-adjacent

environments may replace one another.