Floian

The Floium is in Earth's history, the second stage of the chronostratigraphic Unterordovizium series of the Ordovician. The beginning is geochronological dating to about 477.7 million years, the end to about 470 million years. The Floium following the Tremadocian and is detached from the Dapingium.

Naming and history

The stage is named after the place in Västergötland Flo ( southern Sweden). The name was suggested by Stig M. Bergström, Anita Löfgren and Jörg Maletz until 2004. The Floium corresponds to the lower part of the former Arenigium series ( or level).

Definition and GSSP

The lower limit is defined approximatus with the first appearance of the graptolite - type Tetragraptus. The upper limit of Floium (or the subsequent stage of Dapingiums lower limit) is defined by the first appearance of the conodont species Baltoniodus triangularis. The official reference profile ( GSSP = " Global Stratotype Section and Point" ) for the Floium lies in the quarry Diabasbrottet, about 5 km north- west of the village Flo in Västergötland ( southern Sweden).