Folk Classification Scheme Flashcards

Micrite Classification

• Micrite matrix containing 0-1% allochems is classified as Micrite.
• Micrite matrix with 1-10% allochems is termed Fossil-iferous Biomicrite, indicating the presence of fossils.
• For micrite matrix consisting of 10-50% allochems, the classification is Sparse Biomicrite, showing a moderate abundance of allochems.
• When the micrite matrix contains over 50% allochems, it is known as Packed Biomicrite, indicating a dense concentration of allochems.

Spar Cement Classification

• Subequal Spar and Micrite refers to a type of biosparite that is poorly washed, revealing a mix of spar and micrite.
• Spar Cement with poor sorting results in Unsorted Biosparite, where grains lack uniformity in size and distribution.
• Spar Cement with good sorting is categorized as Sorted Biosparite, indicating a homogenous grain size and better arrangement.
• Rounded and abraded Spar Cement signifies Rounded Biosparite, suggesting that the grains have undergone significant transport and wear.

Deposition Environments

• Quiet water deposition is associated with Micrite, reflective of environments with low energy where fine particles settle slowly.
• High wave current activity leads to the formation of Rounded Biosparite, where strong currents affect grain shape and size.

Fossil and Ooid Prefixes

• The prefix bio is used for fossils, indicating biological origin.
• The prefix oo denotes ooids, which are small, minimally lithified grains often formed in marine environments.
• The prefix pel relates to peliods, small grains similar to ooids but differing in origin and formation.
• The prefix intra is used for intraclasts, which are fragments of pre-existing carbonate materials.