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Geologic Time Scale Updated

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piranha

The noticeable change in the Cambrian is the Wuliuan Stage replaces the provisional "Cambrian Stage 5".

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Wrangellian

Ah, thanks, I was wondering when the next update would come out!

 

12 hours ago, piranha said:

The noticeable change in the Cambrian is the Wuliuan Stage replaces the provisional "Cambrian Stage 5".

And Series 3 is now the Miaolingian.

Another Chinese name... no surprise. The Drumian sort of looks out of place there.  Are there any strata outside of China that are in the running for the other names? Seems China ended up with all the best (intact) Cambrian sequences.

 

I wonder why they haven't yet named the upper two stages of the Pleistocene... I thought they were going to be called the Ionian and Tarantian, but they seem to have backed away from those.

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Oxytropidoceras

Wrangellian wrote:

 

"Another Chinese name... no surprise. The Drumian sort of looks out of place there.  Are there any strata outside of China that are in the running for the other names? Seems China ended up with all the best (intact) Cambrian sequences."

 

It is not so much that "...China ended up with all the best (intact) Cambrian sequences." It is that the Chinese government has been quite generous, relative to other countries, in funding paleontological research into Cambrian paleontology and stratigraphy. Thus, they have best documented and studied sequences, which is essential for establishing stratotypes. 

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piranha

3.c. Cambrian Stage 5
A proposal for the Wuliuan Stage (formerly provisional Stage 5) and the Miaolingian Series (formerly provisional Series 3) was overwhelmingly approved within the ISCS in 2017 (balloting in October–November) and will soon be forwarded to ICS for approval.  The base of the Wuliuan Stage and the Miaolingian Series coincides with the FAD of the oryctocephalid trilobite Oryctocephalus indicus, and the proposed GSSP section, the Wuliu-Zengjiayan section, is at Balang Village in the Miaoling Mountains, eastern Guizhou, China.   LINK

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Wrangellian
8 hours ago, Oxytropidoceras said:

Wrangellian wrote:

 

"Another Chinese name... no surprise. The Drumian sort of looks out of place there.  Are there any strata outside of China that are in the running for the other names? Seems China ended up with all the best (intact) Cambrian sequences."

 

It is not so much that "...China ended up with all the best (intact) Cambrian sequences." It is that the Chinese government has been quite generous, relative to other countries, in funding paleontological research into Cambrian paleontology and stratigraphy. Thus, they have best documented and studied sequences, which is essential for establishing stratotypes. 

Ah, there is that. I've often wondered if there were more/better sequences elsewhere that haven't been (fully) studied yet, but had assumed all the most extensive and scientifically useful sequences would have been known already, and that the best ones would have been selected for staking out the Geologic Time Scale regardless of what country they were in.

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Wrangellian
4 hours ago, piranha said:

3.c. Cambrian Stage 5
A proposal for the Wuliuan Stage (formerly provisional Stage 5) and the Miaolingian Series (formerly provisional Series 3) was overwhelmingly approved within the ISCS in 2017 (balloting in October–November) and will soon be forwarded to ICS for approval.  The base of the Wuliuan Stage and the Miaolingian Series coincides with the FAD of the oryctocephalid trilobite Oryctocephalus indicus, and the proposed GSSP section, the Wuliu-Zengjiayan section, is at Balang Village in the Miaoling Mountains, eastern Guizhou, China.   LINK

Thanks for the link.

 

Extract:

 

"Following a decision on Stage 10, provisional stages 2, 3, and 4, are expected to be defined in rapid succession. A decision on the preferred GSSP horizon of any one of the three stages will restrict choices for the remaining two stages, so the ISCS is approaching work toward definition of the three stages as closely linked.
4) A more long-term objective is re-examination of the Cambrian System (Terreneuvian Series, Fortunian Stage) GSSP. Imprecision in correlating the lower boundary of the Cambrian System has been encountered on all palaeocontinents, and the ISCS is now engaged in seeking a practical solution to remedy the problem (see Babcock, L.E. et al. 2014: Proposed reassessment of the Cambrian GSSP. Journal of African Earth Sciences 98, 3–10). A decision on how to proceed with the Cambrian GSSP is expected to be made following ratification of GSSPs for stages 2, 3, and 4."

 

So it looks like 2,3,4 will probably all have names from one country/region...

And if the base of the Cambrian/Terreneuvian/Fortunian ends up being redefined, where might the replacement GSSP be found?  Hmmm...

 

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GordonC

Why is there a large uncertainty (if that is the right term) for the dating of the Silurian -Devonian boundary? G

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