STRATIGRAPHIC TERMINOLOGY, NOMENCLATURE AND CLASSIFICATION

AN OVERVIEW OF STRATIGRAPHIC TERMINOLOGY, NOMENCLATURE, AND CLASSIFICATION

• A key discipline of geology, stratigraphy is the examination of the order, age, and relationship of rock strata.
• The establishment of a uniform system of vocabulary, nomenclature, and categorization is crucial for the efficient communication and comprehension of geological formations.

• Stratigraphic Unit: A rock body owning unique features that enable its mapping and description as a cohesive entity.
• A lithostratigraphic unit is a unit described by its lithological features, such as rock type, color, and texture.
• A biostratigraphic unit is a unit that is determined by its fossil richness.
  Chronostratigraphic Unit: A unit determined by its age using absolute dating methods.
• A Time-Stratigraphic Unit is a geometric unit that represents a precise period of geological time.

Lexical Terms

• Stratigraphic units are named according to particular rules in order to guarantee clarity and uniformity.
• Stratigraphic units are often designated based on a geographical position, a unique attribute, or a geological process. For instance:
• Classification of lithostratigraphic units: Sandstone Formation, Limestone Member
• Taxonomic units: Ammonite Zone, Dinosaur Bed
• Chronostratigraphic units: Eocene Epoch, Cretaceous Period

Taxonomy

• Stratigraphic units can be categorized according to their comparative age and vertical location. Principal categorization systems consist of:
• The concept of superposition states that younger rocks are placed on top of older rocks, provided that no major disruption has taken place.

Cross-Cutting Relationships: A geological structure that intersects another is often of a more recent age.

Rock pieces that are incorporated within another rock are of a much older age than the host rock.

Unconformities are gaps in the geological record that indicate historical periods of erosion or lack of deposition.

Stratigraphic Correlations

• Effective correlation of stratigraphic units from several places is essential for comprehending the geological history of a broader area. This entails the identification of common features, such as lithology, fossil fossils, and age correlations. Some methods employed for correlation analysis are:
• The lithostratigraphic correlation is established by comparing rock types and their sequences.
• Biostratigraphic correlation is determined by the existence and spatial arrangement of fossil remains.
• Chronostratigraphic correlation is established using absolute age measurements.

Additional Considerations

• Facies refer to the horizontal separation of rock groups caused by changes in the conditions under which they were deposited.
• Correlation charts are graphical depictions of associations and connections among stratigraphic features.
• Codes for Stratigraphic Nomenclature: Global recommendations and benchmarks for stratigraphic nomenclature.

IMAGE SOURCE (THUMBNAIL)