This transformation into a different nuclide can be accomplished in different ways.
Alpha decay is a type of radioactive decay where an alpha particle is emitted.
The sediment of this area was laid down after ammonite A appeared 199 million years ago, and before ammonite B became extinct 195 million years ago.
This narrows the date of the delta beds to the four million years between these dates.
The second method is called absolute dating and is done by analysing the amount of radioactive decay in the minerals of the rocks.
Scientists find out the age of a dinosaur fossil by dating not only the rocks in which it lies, but those below and above it.
So, to understand this process, we need to know that an alpha particle is two protons and two neutrons bound together, which is the same as a helium nucleus.
In other words, an alpha particle is a helium nucleus.
We call the unstable nuclide that undergoes radioactive decay the parent nuclide and the nuclide that results from the radioactive decay the daughter nuclide.
This is a fairly easy concept to remember because it is as if the original nuclide is giving birth to the new nuclide, much like a human parent and daughter relationship.
Learn about three common types of radioactive decay: alpha decay, beta decay and gamma decay. You simply subtract your birth date from the current date. It was also discovered that these elements decayed into other elements at fixed rates.
So we have to rely on something called radiometric dating to figure out the age of rock.
After another half-life has passed, it will have decayed to an eighth, and so on. The half-life of potassium-40 is 1,310 million years, after which half of its substance will have changed into stable argon-40.