The Tortonian is in the
geologic time scale
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochrono ...
an
age or
stage of the late
Miocene that spans the time between 11.608 ± 0.005
Ma and 7.246 ± 0.005 Ma (million years ago). It follows the
Serravallian and is followed by the
Messinian
The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma (million years ago). It follows the Tortonian and is followed by the Zanclean, the first ...
.
The Tortonian roughly overlaps with the regional Pannonian Stage of the
Paratethys
The Paratethys sea, Paratethys ocean, Paratethys realm or just Paratethys was a large shallow inland sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia.
Paratethys was peculiar due to its pa ...
timescale of Central Europe. It also overlaps the upper
Astaracian,
Vallesian and lower
Turolian European land mammal ages, the upper
Clarendonian and lower
Hemphillian North American land mammal ages and the upper
Chasicoan and lower
Huayquerian South American land mammal ages.
Definition
The Tortonian was introduced by Swiss
stratigrapher
Stratigraphy is a branch of geology concerned with the study of rock layers ( strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks.
Stratigraphy has three related subfields: lithostrat ...
Karl Mayer-Eymar in 1858. It was named after the Italian city of
Tortona in the region