Sandbium
| system | series | step | ≈ age ( mya ) |
|---|---|---|---|
| higher | higher | higher | younger |
| Ordovician | Upper Ordovician | Brain antium | 443.4 ⬍ 445.2 |
| Katium | 445.2 ⬍ 453 |
||
| Sandbium | 453 ⬍ 458.4 |
||
| Middle Ordovician | Darriwilium | 458.4 ⬍ 467.3 |
|
| Dapingium | 467.3 ⬍ 470 |
||
| Lower Ordovician | Floium | 470 ⬍ 477.7 |
|
| Tremadocium | 477.7 ⬍ 485.4 |
||
| deeper | deeper | deeper | older |
The sandbium is the lowest chronostratigraphic level of the Upper Ordovician series of the Ordovician in the history of the earth . Geochronologically, the stage roughly corresponds to the period from around 458.4 to around 453 million years. The Sandbium follows the Darriwilium and is replaced by the Katium .
Naming and history
The name of the stage is derived from the locality Södra Sandby . The name was proposed by a group of scientists around Stig Bergström in 2006.
Definition and GSSP
The lower limit is defined by the first appearance of the graptolite species Nemagraptus gracilis . The upper limit is the first appearance of the graptolite species Diplacanthograptus caudatus . The limit also coincides with the lower limit of the "Guttenberg carbon-13 isotope excursion", a deviation in the C13 isotope ratio that can be observed worldwide. The official reference profile (GSSP = "Global Stratotype Section and Point") for the Sandbium are four natural outcrops along the Sularp stream near Fågelsång , 8 km east of the center of Lund and 1.5 km west of Södra Sandby in Skåne ( southern Sweden ).
literature
- SM Bergström, SC Finney, Xu Chen, C. Pålsson, Zhi-lao Wang and Y. Grahn: A proposed global boundary stratotype for the base of the Upper Series of the Ordovician System: The Fågelsång section, Scania, southern Sweden. Episodes. 23 (3): 102-109, Beijing 2000 ISSN 0705-3797 .
- Stig M. Bergström, Stanley C. Finney, Chen Xu, Daniel Goldman and Stephen A. Leslie: Three new Ordovician global stage names. Lethaia, 39: 287-288, Oslo 2006 ISSN 0024-1164 .
- Felix Gradstein, Jim Ogg and Alan Smith: A Geologic timescale. Cambridge University Press 2004 ISBN 978-0-521-78673-7 .
Web links
- International Stratigraphic Chart 2012 (PDF)
- German Stratigraphic Commission, Manfred Menning (Hrsg.): Stratigraphische Tisch von Deutschland 2002 . Potsdam 2002, ISBN 3-00-010197-7 (1 sheet, Stratigraphie.de [PDF; 6.6 MB ]).
- Commission for the paleontological and stratigraphic research of Austria of the Austrian Academy of Sciences (Ed.): The Stratigraphic Table of Austria (sedimentary layer sequences). Vienna 2004 (PDF; 376 kB)