Talk:Stratigraphy of the Cambrian

Stratigraphic Implications of Treptichnus pedum

 * "Stratigraphic Implications. Stratigraphic boundaries must be defined by stratotypes that can be referred to in other sections. Working groups of the International Correlation Programs democratically decide, in which country and at what level to put the “Golden Spike”. Nevertheless such decisions have a subjective (if not political) element.


 * Of the many changes that took place in the transition from the Proterozoic to the Phanerozoic Era, the onset of vertical bioturbation is just one. Treptichnus pedum has the advantage that it is distinctive, common and can be recognized in a variety of facies. On the other hand, it could be argued whether this burrow really represents vertical bioturbation or just a more sophisticated mode of undermat mining.


 * Thus it is not surprising that the first appearance does not exactly coincide with other bioevents, such as the disappearance of the formerly ruling vendobionts, the radiation of “small shelly fossils”, and eventually of the trilobites. In fact, Treptichnus pedum has lately been found in association with the last vendobionts in Australia and Namibia. Thus it is formally true to say that these strange organisms survived into the Early Cambrian, even though their extinction, and with it the demise of the Ediacaran ecosystem, was certainly more decisive. Possibly geochemical or paleomagnetic excursions would in this case be better chronometers than guide fossils; but unfortunately they cannot be recognized right in the field!"

Treptichnus pedum have very big time range: Uppermost Precambrian to Middle Cambrian, Lower Ordovician! Alecsey(Alnagov (talk) 09:02, 9 May 2009 (UTC))

Articles about treptichnid traces
- systematica of "Treptichnus pedum" traces; redescription of type species Treptichnus pedum (T. pedum from GSSP) as Podolodes pedum; interpretation ''Didymaulichnus cf. tirasensis'' as treptichnid. Aleksey(Alnagov (talk) 20:38, 10 May 2009 (UTC))


 * Inserting into Trichophycus pedum. Martin  (Smith609 – Talk)  15:26, 11 May 2009 (UTC)

Amount of species of Early Cambrian fossils in key regions
Source:

Aleksey(Alnagov (talk) 19:26, 10 May 2009 (UTC))


 * What is the significance of this data? How has it been statistically corrected for differences in exposure, collection bias, etc? Martin  (Smith609 – Talk)  15:24, 11 May 2009 (UTC)

Cambrian system in ...
You can use and modify this scheme. Aleksey (Alnagov (talk) 13:31, 23 August 2009 (UTC))