Pretty obvious that the dike came after the rocks it cuts through, right?
That’s because zircon is super tough – it resists weathering. Each radioactive isotope works best for particular applications.
The half-life of carbon 14, for example, is 5,730 years.
What’s more, if the whole rock is badly weathered, it will be hard to find an intact mineral grain containing radioactive isotopes.
You might have noticed that many of the oldest age dates come from a mineral called zircon.
In a way this field, called geochronology, is some of the purest detective work earth scientists do.
There are two basic approaches: relative age dating, and absolute age dating.
Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering—the reason Jesus came into the world (See Six Days? He said, This only makes sense with a time-line beginning with the creation week thousands of years ago.
It makes no sense at all if man appeared at the end of billions of years.
The narrower a range of time that an animal lived, the better it is as an index of a specific time.
No bones about it, fossils are important age markers.
Look for “absolute” ages such as cornerstones, dates carved into fresh concrete, or dates stamped on manhole covers.