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Jens Gast
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Verfasst am: Mo Okt 10, 2005 5:26 pm Titel: Potential for a GSSP in the Middle Cambrian of Utah |
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Here is a interesting article about stratigraphy and correlation by using the agnostid Ptychagnostus atavus, whom is wellknown from several different parts off the world.
Loren E. Babcock, Margaret N. Rees, Richard A. Robison, Elizabeth S. Langenburg and Shanchi Peng (2004): Potential Global Standard Stratotype-section and Point (GSSP) for a Cambrian stage boundary defined by the first appearance of the trilobite Ptychagnostus atavus, Drum Mountains, Utah, USA. - Geobios, 37 (2) , 149-158.
Abstract
The base of the Ptychagnostus (or Acidusus) atavus Zone is one of the most clearly recognizable horizons on an intercontinental scale in the Cambrian System, and would serve as an excellent position for the base of a new stage-level chronostratigraphic subdivision. Among well-exposed, readily accessible sections in Laurentia, the "Stratotype Ridge" section, Drum Mountains, western Utah, USA, is perhaps the most suitable for a Global Standard Stratotype-section and Point (GSSP) defined by the first appearance datum (FAD) of the cosmopolitan agnostoid trilobite P. atavus. In the "Stratotype Ridge" section, the FAD of P. atavus occurs near the base of a calcisiltite bed 62 m above the base of the Wheeler Formation. A position corresponding closely to this horizon can be recognized with precision in Gondwana, Siberia, Kazakhstan, and Baltica using a combination of stratigraphic tools, the most useful of which are trilobite biostratigraphy, conodont biostratigraphy, and sequence stratigraphy. Brachiopod biostratigraphy and chemostratigraphy provide general constraints on the position of the horizon intercontinentally.
Greetings,
Jens |
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baby4423 Gast
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Verfasst am: Di Dez 06, 2005 12:09 am Titel: Need to know |
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Jens hat Folgendes geschrieben: | Here is a interesting article about stratigraphy and correlation by using the agnostid Ptychagnostus atavus, whom is wellknown from several different parts off the world. |
I really need to know more about this... school project. Can you PM me some more ideas? |
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Jens Gast
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Verfasst am: Do Dez 08, 2005 9:16 pm Titel: Re: Need to know |
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baby4423 hat Folgendes geschrieben: | Jens hat Folgendes geschrieben: | Here is a interesting article about stratigraphy and correlation by using the agnostid Ptychagnostus atavus, whom is wellknown from several different parts off the world. |
I really need to know more about this... school project. Can you PM me some more ideas? |
We can, but try not to spam. |
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