Space
| series | step | Lower level | ≈ age ( mya ) |
|---|---|---|---|
| higher | higher | higher | younger |
| Lower Triassic | Olenekium | Space | 249.2-247.2 |
| Smithium | 251.2-249.2 | ||
| Indusium | Servantium | 251.6-251.2 | |
| Griesbachium | 251.9-251.6 | ||
| deeper | deeper | deeper | older |
Spathium (English Spathian) is in the history of the earth the upper lower level of the Olenekian , the second level of the Lower Triassic . It follows the Smithium , the lower subgrade of the Olenekium, and is replaced by the Aegeum , the lowest subgrade of the Anisium .
Concept history
The Spathium is named after Spath Creek in the northwest part of Ellesmere Island . This stream is in turn named after Leonard Frank Spath , an English paleontologist who mainly worked on ammonites . The level and name were proposed by Edward Timothy ("Tim") Tozer in 1965.
Definition, correlation, absolute dating and subdivision
The spathe is characterized by the occurrence of the ammonite genera Tirolites , Columbites , Subcolumbites , Prohungarites and Keyserlingites . Tozer placed the lower limit at the base of the Subolenekites pilaticus zone. However, an ammonite zone seems to be missing in the type profile in the transition area Griesbachium / Dienerium. The upper limit of the spatium is close to the first appearance of the ammonite genera Japonites , Paradanubites and Paracrochordiceras and the first appearance of the conodont species Chiosella timorensis .
The space is correlated with the upper oleic. The same limits are assumed for the lower level Russium ; this lower level was suggested by Zakharov (1994) because the space at the type locality is not completely occupied by ammonites. However, the russium did not find acceptance.
This section of the earth's history is geochronologically dated to about 249.2 to 247.2 million years ago. For the alternative dating of the Lower Triassic see (Brack et al. 2005).
The spatium includes the following ammonite zones:
- Prohungarites subcolumbites
- Procolumbites
- Columbites parisianus
- Tirolites cassianus
Although there is no "official", i. H. is recognized and defined by the International Commission on Stratigraphy (ICS), but is simply referred to as an "informal" time interval, the space is also used in more recent works on the Lower Triassic.
supporting documents
Individual evidence
- ^ Frisch, Thomas (2011): Edward Timothy Tozer (1928-2010). Arctic, 64 (3): 388-389, Calgary. PDF
- ↑ Zakharov, Yuri D. (1994): Proposals on revision of the Siberian standard for the Lower Triassic and candidate stratotype section and point for the Induan-Olenekian boundary. Albertiana, 14: 44-51, Utrecht. PDF ( page no longer available , search in web archives )
- ↑ TimeScale Creator 5.0 download page
- ↑ Brack, Peter, Hans Rieber, Alda Nicora and Roland Mundil (2005): 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): 233-244, Beijing ISSN 0705-3797 PDF ( Memento of the original from December 27, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ Galfetti, Thomas, Peter A. Hochuli, Arnaud Brayard, Hugo Bucher, Helmut Weissert & Jorunn Os Vigran: Smithian-Spathian boundary event: Evidence for global climatic change in the wake of the end-Permian biotic crisis. Geology, 34 (4): 291-294 doi : 10.1130 / G23117A.1
literature
- Tozer, Edward Timothy (1965): Lower Triassic stages and ammonoid zones of Arctic Canada. Geological Survey of Canada Paper, 65-12: 1-14, Ottawa.
- Tozer, Edward Timothy (1967): A standard for Triassic time. Geological Survey of Canada Bulletin, 156: 1–103, Ottawa.
- Gradstein, Felix, James Ogg & Alan Smith (2004): A Geologic Time Scale 2004. 589 pp. Cambridge University Press, Cambridge ISBN 0521781426