Aalenium
system | series | step | ≈ age ( mya ) |
---|---|---|---|
higher | higher | higher | younger |
law | Upper Jurassic | Tithonium | 145 ⬍ 152.1 |
Kimmeridgium | 152.1 ⬍ 157.3 |
||
Oxfordium | 157.3 ⬍ 163.5 |
||
Middle Jurassic | Callovium | 163.5 ⬍ 166.1 |
|
Bathonium | 166.1 ⬍ 168.3 |
||
Bajocium | 168.3 ⬍ 170.3 |
||
Aalenium | 170.3 ⬍ 174.1 |
||
Lower Jurassic | Toarcium | 174.1 ⬍ 182.7 |
|
Pliensbachium | 182.7 ⬍ 190.8 |
||
Sinemurium | 190.8 ⬍ 199.3 |
||
Hettangium | 199.3 ⬍ 201.3 |
||
deeper | deeper | deeper | older |
The Aalenian (German shortens Aalen, also Aalenien ) is in the Earth's history , the oldest of the four chronostratigraphic stage of the Middle Jurassic and includes geochronological the period of about 174.1 to 170.3 million years ago. The Toarcium precedes this stage ; it is followed by the Bajocium .
Naming and history
The stage is named after the city of Aalen in Baden-Württemberg . The step and name were first used by Karl Mayer-Eymar in 1864. The first fossil finds were made in the deep tunnel in Aalen. A large part of this is exhibited in the city's Urweltmuseum Aalen .
Definition and GSSP
The beginning (the base) of the stage is defined by the first appearance of the ammonite genus Leioceras . The first appearance of the ammonite genus Hyperlioceras marks the end of the stage or the base of the subsequent Bajocium. The Global Stratotype Section and Point (GSSP, the type profile of the basal unit boundary ) of the Aalenium is located in an outcrop approx. 500 m north of the village of Fuentelsaz (Guadalajara Province, Spain) in the Iberian Mountains .
Subdivision of the Aalenium
The Aalenian will Tethysbereich in the following ammonite - biozones divided:
Lower level | Biozone | Index fossil |
---|---|---|
Oberaalenium | concavum | Graphoceras concavum |
bradfordensis | Brasilia bradfordensis | |
murchisonae | Ludwigia murchisonae | |
Unteraalenium | opalinum | Leioceras opalinum |
literature
- S. Cresta, A. Goy, S. Ureta, C. Arias, E. Barrón, J. Bernad, ML Canales, F. García-Joral, E. García-Romero, PR Gialanella, JJ Gómez, JA González, C. Herrero, G. Martínez, ML Osete, N. Perilli and JJ Villalaín: The Global Boundary Stratotype Section and Point (GSSP) of the Toarcian-Aalenian Boundary (Lower-Middle Jurassic). Episodes, 24 (3), Beijing 2001, pp. 166-175 PDF .
- Felix Gradstein, Jim Ogg, Jim Smith, Alan Smith: A Geologic timescale. Cambridge University Press, 2005, ISBN 978-0-521-78673-7 .
- Karl Mayer-Eymar: Tableau synchronistique des terrains jurassiques. 1 table, Zurich 1864.
- 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)
- “The Aalenium”, article by Ulrich Sauerborn on urweltmuseum-aalen.de
- Aalen Primeval World Museum
- Deep gallery basking
- Homepage Urweltmuseum Aalen, City of Aalen