Norium
| system | series | step | ≈ age ( mya ) |
|---|---|---|---|
| higher | higher | higher | younger |
| Triad | Upper Triassic | Rhaetium | 201.3 ⬍ 208.5 |
| Norium | 208.5 ⬍ 228 |
||
| Carnium | 228 ⬍ 235 |
||
| Middle Triassic | Ladinium | 235 ⬍ 242 |
|
| Anisium | 242 ⬍ 247.2 |
||
| Lower Triassic | Olenekium | 247.2 ⬍ 251.2 |
|
| Indusium | 251.2 ⬍ 251.9 |
||
| deeper | deeper | deeper | older |
The Norium ( Nor ) is the middle chronostratigraphic level of the Upper Triassic in the history of the earth , which geochronologically corresponds to the period about 228 to about 208.5 million years ago and thus lasted about 19.5 million years. The previous stage is the carnium , the next stage the rhaetium .
Naming and history
The original type locality is in the Noric Alps (Austria), which gave the stage its name. Edmund von Mojsisovics suggested the level and name in 1869.
Definition and GSSP
The beginning of the stage is defined by the base of the ammonite zone Klamathites macrolobatus or Stikinoceras kerri and the conodont zones Metapolygnathus communisti or Metapolygnathus primitius . The end of the stage was defined as the first appearance of the ammonite species Cochloceras amoenum . In addition, the conodonts Misikella spp. and Epigondolella mosheri , as well as the radiolarian species Proparvicingula moniliformis . An official GSSP (globally valid type locality and type profile) has not yet been adopted.
Breakdown
In the Tethys area, norium is divided into six ammonite zones:
- Halorites macer zone
- Himavatites hogarti zone
- Cyrtopleurites bicrenatus zone
- Juvavites magnus zone
- Malayites paulckei zone
- Guembelites jandianus zone
Regionally, the norium is divided into the lower grades Lacium (Lac), Alaunium (Alaun) and Sevatium (Sevat).
credentials
- ↑ according to Brack et al. (2005): 226 to 207 million years
literature
- Peter Brack, Hans Rieber, Alda Nicora and Roland Mundil: The Global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale. Episodes, 28 (4): pp. 233-244, Beijing 2005 ISSN 0705-3797 .
- Felix Gradstein, Jim Ogg, Jim & Alan Smith: A Geologic timescale. Cambridge University Press 2005, ISBN 978-0-521-78673-7
- Hans Murawski & Wilhelm Meyer: Geological dictionary . 10., rework. u. exp. Ed., 278, Enke Verlag, Stuttgart 1998, ISBN 3-432-84100-0 .
Web links
- 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)
- International Chronostratigraphic Chart 2012 (PDF)