Ivorium
structure
The Ivorian is a period of the Carboniferous in the history of the earth . It is the upper regional lower level (also used as a level by some authors) of the regional and global level of the Tournaisium in Belgium . In absolute terms, the Ivorian lasted from about 351.5 to about 345.5 million years. In the level / sub-level structure of the Karbon in Belgium, the Ivorium is preceded by the Hastarium , followed by the Moliniacium , the lower regional sub-level of the Viséum .
History and naming
The lower level or level is named after the place Yvoir , on the right bank of the Meuse, between Namur and Dinant (Belgium). The Ivorium was originally proposed as a level by Raphael Conil , Eric Groessens and Henri Pirlet in 1977, but was mostly used as a lower level by later authors. According to the Stratigraphic Table of Germany 2002, it is also available in Germany as a lower level of the Tournaisium.
Definition and correlation
The base of the ivorium is defined by the first appearance of the conodonts - (sub) species Polygnathus communis carina . The first appearance of the foraminifera species Eoparastaffella simplex marks the base of the subsequent Moliniacium and thus also the upper limit of the Ivorium. The Ivorium is now correlated with the upper part of the Tournaisium.
The absolute age of the Ivorium is disputed. According to Menning et al. (2000) it lasted from 348 to 342.5 million years, according to the Stratigraphic Table of Germany 2002 (STD2002) the Ivorian ranges from about 351.5 to about 345.5 million years. With a duration of 3.7 million (from 349 to 345.3), it is the shortest in the Geological Time Scale 2004 (GTS2004).
Breakdown
The ivorium can be subdivided biostratigraphically into the foraminifera zone MFZ5 to MFZ8. In the succession of rugose corals , it occupies zones RC3 and the lower part of RC4.
swell
Individual evidence
- ↑ according to the Stratigraphic Table of Germany. These ages differ slightly from the ages in the International Stratigraphic Chart from 2009
- ↑ a b c Hance et al. (2006: p. 117ff.)
- ↑ see Weyer & Menning (2006: p. 28, table 1), comparisons of several time scales
- ^ Felix M. Gradstein et al .: A geologic time scale 2004 . 589 pp., Cambridge Univ. Press, Cambridge 2004. ISBN 0-521-78673-8 and ISBN 0-521-78142-6
literature
- Raphael Conil, Eric Groessens and Henri Pirlet: Nouvelle charte stratigraphique du Dinantien type de la Belgique. Annales de la Société géologique du Nord, 96: 363-371, Lille 1977 ISSN 0767-7367
- Luc Hance, Édouard Poty and François-Xavier Devuyst: Ivorian. Geologica Belgica 9 (1-2): 117-122 Brussels 2006 PDF
- Dieter Weyer and Manfred Menning: Geological time scale, stratigraphic nomenclature and magnetostratigraphy. In: Stratigraphie von Deutschland VI Unterkarbon (Mississippium) , series of publications by the German Society for Geosciences, 41: 27-50, Hannover 2006 ISBN 3-932537-37-8 .
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 ]).