Layers of volcanic ash are igneous deposits, while layers of rock these deposits surround are usually sedimentary. Igneous intrusions form when magma breaks through a layer of rock from beneath, or lava flows down from above. When igneous intrusion causes newer sedimentary layers to sink into older ones, it's called subsidence.
When they break and engulf chunks of sedimentary rocks, it's called stoping. The original rock layers around subsidence areas are called wall rocks and the layers that xenoliths came from are called parent rocks.
In historical geology, the primary methods of absolute dating involve using the radioactive decay of elements trapped in rocks or minerals, including isotope systems from very young (radiocarbon dating with Radiometric dating is based on the known and constant rate of decay of radioactive isotopes into their radiogenic daughter isotopes.
Particular isotopes are suitable for different applications due to the type of atoms present in the mineral or other material and its approximate age.
An absolute age is one determined usually by mass-spectrometry where an isotope is measured and then an age can be calculated (a very very basic explanation).
So in the end you can say this fossil is 50 thousand years old (always with an associated uncertainty).
For example, techniques based on isotopes with half lives in the thousands of years, such as Carbon-14, cannot be used to date materials that have ages on the order of billions of years, as the detectable amounts of the radioactive atoms and their decayed daughter isotopes will be too small to measure within the uncertainty of the instruments.
One of the most widely used and well-known absolute dating techniques is carbon-14 (or radiocarbon) dating, which is used to date organic remains.
So I can say the second layer is younger than the first and older than the third but I have no idea whether the cake is 5 minutes or 5 million years old.Igneous rocks form from eruptions of lava or magma.Metamorphic rock is formed by great pressure far below the Earth's surface. Sedimentary rocks form from soil and silt carried and deposited by moving water.Over time, the accumulated deposits compress and harden.Sometimes beds of rock can turn over the other way, so be very cautious when relatively dating rocks!