Silurian#Ludlow

The Ludlow (rarely also Ludlowium or Ludlovium ) is in Earth's history, a chronostratigraphic series within the Silurian. She began geochronological before about 427.4 million years ago and ended about 423 million years. The Ludlow is preceded by the Wenlock series; it is followed by the Pridolium series.

Naming and history

The Ludlow is named after the town of Ludlow in Shropshire (England), are present at the surface in the vicinity rocks of this age. Roderick Murchison introduced the term in 1833 in the literature. Originally, the Ludlow had before 1989 was given the rank of a hierarchical level to the rank of a series.

Definition and GSSP

Ludlow which begins with the base of the Gorstium, which is defined by the (local ) inserting the acritarchs type Leptobrachion longhopense. This limit is probably near the base of Neodiversograptus nils soni Graptolithenzone. The border to Pridolium other hand, is defined by the first appearance of the graptolite - type Monograptus parultimus clearly. The official reference profile ( GSSP = " Global Stratotype Section and Point" ) for the Gorstium located at the abandoned quarry "Pitch Coppice ", about 4.5 km south-west of Ludlow on the south side of the road from Ludlow by Wigmore.

Subdivision

The Ludlow series of Silurian is divided into two geological stages:

• System: Silurian ( 443.4 to 419.2 mya ) Series: Pridolium ( 423 to 419.2 mya ) (not divided into more stages )
• Series: Ludlow ( 427.4 to 423 mya ) Level: Ludfordium ( 425.6 to 423 mya )
• Level: Gorstium ( 427.4 to 425.6 mya )