Stratigraphy - Chronostratigraphy

Chronostratigraphy

Chronostratigraphy is the branch of stratigraphy that studies the absolute, not relative, age of rock strata. The branch is based upon deriving geochronological data for rock units, both directly and inferentially, so that a sequence of time-relative events of rocks within a region can be derived. In essence, chronostratigraphy seeks to understand the geologic history of rocks and regions.

The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geological region and, eventually, the entire geologic record of the Earth.

A gap or lacuna in the geological record may be caused by erosion, in which case it is called a vacuity, or by non-deposition, where is known as a stratigraphic hiatus. It is called a hiatus because deposition was on hold for a period of time. A physical lacuna may represent both a period of non-deposition and a period of erosion. A fault may cause the appearance of a hiatus.