I think I may have misstated my pastor's position on this.
He basically said, that of the 80 or so methods of determining the age of the earth, scientists pick only those that give them the ages they are look for, and reject all the others that return a young earth age.
He said there are four methods that scientists use:
- Argon [something]*
- Potassium [something]*
- Uranium [something]*
- Krypton [something]*
He went on to say that the other 76-some are rejected for one reason or another:
- moondust
- strength of the earth's magnetic field
- ocean salinity
- a bunch of others
* He gave the exact names, but I can't remember them.
I think the book
A Case for a Creator, by Lee Strobel mentions them all as well, weatherman.