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Re: Idle question on Cretaceous chronostratigraphy

To: DML <dinosaur@usc.edu>
Subject: Re: Idle question on Cretaceous chronostratigraphy
From: David Marjanovic <david.marjanovic@gmx.at>
Date: Thu, 22 Mar 2007 23:56:27 +0100
References: <95d00c5f0703221328h6c395f45tcd48567a557e2b2d@mail.gmail.com>
Reply-to: david.marjanovic@gmx.at
Sender: owner-DINOSAUR@usc.edu

The Cretaceous is the longest period of the Phanerozoic, yet also the
only one divided into only two epochs (Lower and Upper Cretaceous) in
the ICS chart. Is there a rational explanation for this somewhat
surprising state of affairs, or did it just "happen"?


It did just happen.

Glut's Encyclopedia recognizes a "Middle Cretaceous", apparently without knowing that this kind of nomenclature is regulated and can't just be introduced by usage. It consists of the Albian and Cenomanian, which makes a lot of sense -- there were mass extinctions at both ends, but IIRC none between the Albian and the Cenomanian.

References:
- Idle question on Cretaceous chronostratigraphy
  - From: Andreas Johansson <andreasj@gmail.com>

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