Just in case somebody wants to get a bigger picture of the subject rather than the agenda of the ICR.
http://en.wikipedia.org/wiki/Geochronology
This has become “a battle of the theologies” as much as anything else.
Anything happening prior to a change in metaphysics automatically raises questions about applying our ideas of physics to it. That includes everything from the rate of uranium decay to whether it makes sense to deem a day to be 24 * 60 minutes as we know them.