When did the cretaceous end?

[doushantuo]

Trilo,the base of the danian has been astronomically calibrated in the Zumaia section,Spain(basalmost Danian).

The "Strange section" starts with a package of 17 precessional cycles(Magnetochron 29R(eversed)

Obviously,the the sun is the true chronometer in this case

edit:one of the authors in the following piece is Laskar,Nestor of astronomical tuning

PALEOG

 

(slightly less than 7 Mb )(G3 is more or less free access,with a sliding endpoint(about one year before the current (latest)issue

 

 

 

 

 

 

 

 

 

[LabRatKing]

9 hours ago, siteseer said:

I always understood the iridium layer to be neither Cretaceous nor Paleocene but THE boundary - the line/zone between them.  If there was more than one impact over hundreds or thousands of years and the layer/layers was/were deposited over that amount of time, it would still be virtually instantaneous from a geologic standpoint.  It's like asking what time of day the Cretaceous ended (relative vs. absolute as we learned in geology class).  We will likely never reach that level of resolution so the boundary might still move or get thinner or thicker.  When I was a kid, the number was 60-65 million years ago.

 

Jess

It can get confusing for many due to the misuse/ misunderstanding of the terms  K-T and K-Pg when discussing the boundary. I blame this on the very low standards for what passes for SciComm on the interwebs.

[doushantuo]

hear you