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RE: Age of Archaeoceratops




-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Marco Auditore
Sent: Monday, May 20, 2002 2:16 PM
To: dinosaur@usc.edu
Subject: Re: Age of Archaeoceratops

At 22.48 20/05/2002 +0200, you wrote:
>Dear ListMembers, I'm very grateful if someone could tell me the exact age
>of Archaeoceratops oshimai, in my data-file I've:
>Archaeoceratops Dong, Azuma, 1997
>A. oshimai Dong, Azuma, 1997
>Occurrence: Xinminbao Group, Gongpoquan Basin of the Mazongshan Area,
>Gansu Province, China.
>Period and age: early Cretaceous
>But the early Cretaceous period include Barresian Valanginian,
>Hauterivian, Barremian (forming Neocomian), Aptian, and Albian, to which
>age corrispond the Xinminbao Group?

Hi Sandro, I'm here again. the age is Neocomian, from "The age of dinosaurs
in Russia and Mongolia".<<


Here in lies the rub, this really doesn't narrow the age down. I've broken
down the time periods in my lists the best I can. Some won't like the way
I've done it, but it's the best way I could think of.

The Cretaceous period is broken down (as all ages) to stages, and epochs.
There are three epochs in the Cretaceous; The Neocomian is a Subepoch of the
Early Cretaceous Epoch, it is further broken down into three stages;
Berriasian, Valanginian, and the Hauterivian. The next Subepoch is the
Gallic, which actually is in both the upper Early Cretaceous Epoch and the
Lower Gulf Epoch (or upper Cretaceous, but I don't think anyone uses the
Gulf Epoch, but if you have subepochs you have to have epochs, IMHO, it's
like having subfamilies without familes, etc). The lower Gallic has the
Barremian, Aptian and Albian (which is middle to late Early Cretaceous
Epoch); the upper Gallic is the Cenomanian then the Turonian. The last
subepoch is the Senonian: Coniacian, Stantonian, Campanian and finally the
Maastrichtian.

Some people just use the subepochs and not the stages. This may be because
they haven't or can't get a more precise age to the formation they are
working in.

Tracy L. Ford
P. O. Box 1171
Poway Ca  92074