Origin of "K/T", once again

[stssram@st.unocal.com (Bob Myers)]

On Nov 17, 20:49, John F. Morrissey wrote:
} Subject: re: Synapsids and Diapsids
> 
> By the way, I thought that the K in "K/T" was from "kreta" (meaning
> "chalk," and referring to the planktonic ooze common at the boundary). 
> Other subscribers have suggested different sources for the K (= different
> words that mean chalk).  Which is correct?

The source for K in K/T, without any doubt, is Cretaceous.  K is the
standard geologic symbol for the Cretaceous.  The T stands for Tertiary,
which is an old term for most of the Cenozoic era, up until the Quaternary
which is the last 2 million years or so.  (The terms Primary and Secondary
have not been used for a long time.)

Indirectly, of course, the K does come from "chalk", but chalk throughout
the Cretaceous, not chalk at the K/T boundary as such.

This reduces your question to, why is the Cretaceous period represented 
by K.  As has been stated before, C is taken by Carboniferous, and C-bar (C
with a horizontal line through it) by Cambrian.   I think the K does come
from German, though; my dictionary says the Latin word was creta, not kreta.



 


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Bob Myers                               Unocal Information Systems Support
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