Westphalian (stage)
The Westfalium (also Westphalian, rarely falsely Westphalium or Westphal ) is in Earth's history, a period of the Carboniferous. It is the average regional level (or subseries ) of the regional subsystem of Silesiums in Central and Western Europe. The Westfalium corresponds to the global levels of the upper Bashkirian and Moscovian of. In absolute terms, took the Westfalium of about 316.5 million to about 305 million years ago. The Westfalium heads the Namurium, it is followed by Stefanium, the highest regional level of Silesium.
History and naming
Name and stage was introduced by Albert de Lapparent and Ernest Munier - Chalmas 1892 in the literature. The name is derived from the landscape Westphalia.
Definition and correlation
The onset is defined by the Ersteinsetzen the ammonite species Gastrioceras subcrenatum ( Schlotheim ). The Westfalium is therefore approximately in the center of the global stage a Bashkirian. The upper limit was in the Central Europe originally a hiatus between Westfalium and Stefanium whose scope is very different. Meanwhile, the upper limit is set equal to the Moscovian / Kasimovian limit. However, the limit Westfalium / Stefanium is very controversial because the Cantabrium, which was inserted between Westfalium and Stefanium and the Stefanium was slammed so far established with certainty only in Cantabria.
According to the uncertain upper limit and the different absolute time scales the Westfalium ranges from 316.5 to 305 million years, or from about 315 to about 307 million years, or after a calibration of the Pennsylvaniums by Menning et al. (2006) by bis 316,5 306 million years
Subdivision
The Westfalium been traditionally divided into four sub-stages in Germany, which have been designated by the letters A, B, C, D. In Belgium and England Westfalium AC were named with its own name:
- Westfalium D
- Bolsovium
- Duckmantium
- Langsettium