The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a
subperiod in the
geologic timescale
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 geoch ...
or a
subsystem of the
geologic record. It is the earlier of two subperiods of the
Carboniferous period lasting from roughly 358.9 to 323.2 million years ago. As with most other
geochronologic units, the
rock beds that define the Mississippian are well identified, but the exact start and end dates are uncertain by a few million years. The Mississippian is so named because rocks with this age are exposed in the
Mississippi Valley.
The Mississippian was a period of
marine transgression in the Northern Hemisphere: the sea level was so high that only the
Fennoscandian Shield and the
Laurentian Shield were dry land. The
cratons were surrounded by extensive delta systems and
lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into '' coastal lagoons'' (or ''barrier lagoons' ...
s, and carbonate sedimentation on the surrounding continental platforms, covered by shallow seas.
In
North America, where the interval consists primarily of marine
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms wh ...
s, it is treated as a geologic period between the
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...
and the
Pennsylvanian Pennsylvanian may refer to:
* A person or thing from Pennsylvania
* Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timesca ...
. During the Mississippian an important phase of
orogeny
Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An '' orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted ...
occurred in the
Appalachian Mountains
The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. The ...
. The USGS geologic time scale shows its relation to other periods.
USGS Timescale
/ref>
In Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...
, the Mississippian and Pennsylvanian are grouped together as the Carboniferous system, and traditionally referred to as the '' Upper Carboniferous'' and ''Lower Carboniferous'' instead.
Subdivisions
In the official geologic timescale, the Mississippian is subdivided into three stages:
* Serpukhovian ( to mya)
* Visean ( to mya)
* Tournaisian ( to mya)
The lower two come from European stratigraphy, the top from Russian stratigraphy. Besides Europe and Russia, there are many local subdivisions that are used as alternatives for the international timescale. In the North American system, the Mississippian is subdivided into four stages:
* Chesterian (top of the Visean plus the Serpukhovian)
* Meramecian (middle Visean)
*Osagean
The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly ...
(top of the Tournaisian and bottom of the Visean)
* Kinderhookian (the lower two-thirds of the Tournaisian)
References
External links
*
*
*01
Geological epochs
*
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