Argon argon dating technique
Other objections raised by creationists are addressed in [Dalrymple2006a].The overall reliability of radiometric dating was addressed in some detail in a recent book by Brent Dalrymple, a premier expert in the field. 80-81]: These methods provide valid age data in most instances, although there is a small percentage of instances in which even these generally reliable methods yield incorrect results.Several hundred laboratories around the world are active in radiometric dating.Their results consistently agree with an old Earth.Some [skeptics] make it sound like there is a lot of disagreement, but this is not the case.The disagreement in values needed to support the position of young-Earth proponents would require differences in age measured by orders of magnitude (e.g., factors of 10,000, 100,000, a million, or more).Another method is to make age measurements on several samples from the same rock unit.This technique helps identify post-formation geologic disturbances because different minerals respond differently to heating and chemical changes.
In the particular case that Morris highlighted, the lava flow was unusual because it included numerous xenoliths (typically consisting of olivine, an iron-magnesium silicate material) that are foreign to the lava, having been carried from deep within the earth but not completely melted in the lava.The differences actually found in the scientific literature are usually close to the margin of error, usually a few percent, not orders of magnitude!Vast amounts of data overwhelmingly favor an old Earth.If two or more radiometric clocks based on different elements and running at different rates give the same age, that's powerful evidence that the ages are probably correct.Along this line, Roger Wiens, a scientist at the Los Alamos National Laboratory, asks those who are skeptical of radiometric dating to consider the following (quoted in several cases from [Wiens2002]): All of the different dating methods agree--they agree a great majority of the time over millions of years of time.
Creationist Henry Morris, for example, criticizes this type of "uniformitarian" assumption [Morris2000, pg. But numerous experiments have been conducted to detect any change in radioactivity as a result of chemical activity, exceedingly high heat, pressure, or magnetic field. Scientists have also performed very exacting experiments to detect any change in the constants or laws of physics over time, but various lines of evidence indicate that these laws have been in force, essentially the same as we observe them today, over the multi-billion-year age of the universe.