What types of rocks are good for radiometric dating

Radiometric dating of rocks and minerals using naturally occurring, long-lived radioactive isotopes is troublesome for young-earth creationists because the techniques have provided overwhelming evidence of the antiquity of the earth and life.

Some so-called creation scientists have attempted to show that radiometric dating does not work on theoretical grounds (for example, Arndts and Overn 1981; Gill 1996) but such attempts invariably have fatal flaws (see Dalrymple 1984; York and Dalrymple 2000).

For example, a geologist may examine a cutting where the rocks appear as shown in Figure 1.

Here he can see that some curved sedimentary rocks have been cut vertically by a sheet of volcanic rock called a dyke.

Young-Earth creationists -- that is, creationists who believe that Earth is no more than 10,000 years old -- are fond of attacking radiometric dating methods as being full of inaccuracies and riddled with sources of error.

When I first became interested in the creation-evolution debate, in late 1994, I looked around for sources that clearly and simply explained what radiometric dating is and why young-Earth creationists are driven to discredit it.

Uranium-lead dating is an established radiometric dating technique.

Very old rocks have been dated by measuring the amount of lead in the mineral zircon (Zr Si O4) which forms with radioactive uranium that takes more than 4 billion years to decay.

All these methods point to Earth being very, very old -- several billions of years old.nts and thus many applications of the basic principle.Examples: Archeologists may employ the well known method of carbon 14 dating.Other creationists have focused on instances in which radiometric dating seems to yield incorrect results.In most instances, these efforts are flawed because the authors have misunderstood or misrepresented the data they attempt to analyze (for example, Woodmorappe 1979; Morris HM 1985; Morris JD 1994).