For other uses, see Mississippian (disambiguation).
- Not to be confused with the "Mississippian period" describing the dominance of the Mississippian culture.
Permian Cisuralian Asselian younger Carboniferous Pennsylvanian Gzhelian 299.0–303.9 Kasimovian 303.9–306.5 Moscovian 306.5–311.7 Bashkirian 311.7–318.1 Mississippian Serpukhovian 318.1–328.3 Viséan 328.3–345.3 Tournaisian 345.3–359.2 Devonian Upper Famennian older Subdivision of the Carboniferous system according to the ICS.
The Mississippian is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earliest/lowermost of two subperiods of the Carboniferous period lasting from roughly 359 to 318 Ma (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 River valley.
In North America, where the interval consists primarily of marine limestones, it was in the past treated as a full-fledged geologic period between the Devonian and the Pennsylvanian. In Europe, the Mississippian and Pennsylvanian are one more-or-less continuous sequence of lowland continental deposits and are grouped together as the Carboniferous system, and sometimes called the Upper Carboniferous and Lower Carboniferous instead. During the Mississippian subperiod an important phase of orogeny occurred in the Appalachian Mountains.
In the official geologic timescale, the Mississippian is subdivided into three stages:
- Tournaisian 359.2 ± 2.5 to 345.3 ± 1.3
- Visean 345.3 ± 2.5 to 326.4 ± 1.3
- Serpukhovian 326.4 ± 2.5 to 318.1 ± 1.3
The first two come from European stratigraphy, the last is 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:
- Kinderhookian (the lower two-thirds of the Tournaisian)
- Osagean (top of the Tournaisian and bottom of the Visean)
- Meramecian (middle Visean)
- Chesterian (top of the Visean plus the Serpukhovian)
- ^ Gradstein et al. (2004)
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