Sandbian

The Sandbium is in Earth's history, the lowest stratigraphic stage of Oberordovizium series of the Ordovician. The level corresponds approximately to the geochronological period of about 458.4 to about 453 million years. The Sandbium following the Darriwilium and is detached from the Katium.

Naming and history

The name of the step is derived from the village of Södra Sandby. The name was proposed by a group of scientists Stig Bergström 2006.

Definition and GSSP

The lower limit is defined by the first appearance of the graptolite - type Nemagraptus gracilis. The upper limit is the first appearance of the graptolite - type Diplacanthograptus caudate. The border coincides with the lower limit of the " Guttenberg carbon isotope excursion -13 " together, a world observed deviation in the C13 isotope ratio. The official reference profile ( GSSP = " Global Stratotype Section and Point" ) for the Sandbium are four natural outcrops along the creek Sularp at Fågelsång, 8 km east of the center of Lund and 1.5 km west of Södra Sandby in Skåne ( southern Sweden).