Air 3 Dotsero Crater

[hank970]

Colorado's youngest volcano, an explosive phreatomagmatic event, erupted just 4150 years ago.

 

[Daniel Mclean]

Wow, epic!

I have one question - how do you know it erupted 4150 years ago and not less? Radiocarbon dating has its problems...

 

[hank970]

Wow, epic!

I have one question - how do you know it erupted 4150 years ago and not less? Radiocarbon dating has its problems...

4150 years, with a margin of error of 300 years plus or minus, is based on radiocarbon dating of wood buried beneath the ejecta. I'm certainly not qualified to challenge that finding. Are you?

 

[Daniel Mclean]

Interesting. I'm not qualified but have done a lot of research in this area. There are three assumptions with this method of dating:

1. When the rock forms (hardens) there should only be parent radioactive atoms in the rock and no daughter radiogenic (derived by radioactive decay of another element) atoms;
2. After hardening, the rock must remain a closed system, that is, no parent or daughter atoms should be added to or removed from the rock by external influences such as percolating groundwaters; and
3. The radioactive decay rate must remain constant.

That means that those assumptions are what they are - assumptions and therefore can't give accurate dates. We don't know if these assumed things were present at the time when the landform was created.

But that's kind of off-topic. I really liked the picture - it looks like a beautiful spot!