Lithostratigraphical units are sedimentary or igneous units that conform to the Law of Superposition. Lithostratigraphy embraces the description, definition and naming of these units, as well as their correlation.
Description of lithostratigraphical units.
When a new unit is defined, or an existing one formally revised, the following should be described:
- Relationship with stratigraphically adjacent units, both vertical and lateral.
- Nature of boundaries: whether gradational or sharp, conformable or unconformable. In particular, describe how the base can be recognized.
- Thickness at the type section and its lateral variation.
- Precise location of the type section, using grid references or, where appropriate, the Global Positioning System (GPS).
Definition of lithostratigraphical units.
Units are defined within a hierarchical framework: