Re: K-T Boundry

[NEIL CLARK <NCLARK@museum.gla.ac.uk>]

> I just heard a lecture on hadrosaurs of the Cretaceous, afterwards
> an interesting discussion took place.  The speaker, Sandy Ludlum, 
says
> that the marine K-T boundry and the terrestrial K-T boundry may not
> coincide with each other.  Anyone have any ideas on this?

As far as I know, all stratotype sections are based on marine 
biostratigraphy and not terrestrial.  The stratotype section for the 
Maastrichtian is in a quarry at St Pietersburg outside of Maastricht 
(South Netherlands) and refers mostly to the later part of the 
Maastrichtian.  The stratotype section for the boundary between the 
Mesozoic and the Caenozoic (as far as I am aware) is at Nye Klor 
(Jutland) [assuming that it has been decided on!].  This means that 
the bondary should be the same the world over.  If it appears that 
there is a discrepancy then it cannot represent the K-T boundary.  All 
potential boundaries have to be comapred with Nye Klor (or the 
stratotype), the problem arises when it is impossible to compare 
sections (as is found with many terrestrial sections).  The only way 
round this is if it is possible to compare dates of terrestrial volcanics 
with those in marine situations that are comparible with the 
stratotype.  Basically, you can't call something a boundary unless 
you can compare it with the stratotype boundary ;-)