Dating of sedimentary rocks senior dating agency co uk
Scientists date igneous rock using elements that are slow to decay, such as uranium and potassium.
By dating these surrounding layers, they can figure out the youngest and oldest that the fossil might be; this is known as "bracketing" the age of the sedimentary layer in which the fossils occur.
Cross-cutting relations can be used to determine the relative ages of rock strata and other geological structures.
Picture from Glen Canyon National Recreation Area, Utah.
The principle of cross-cutting relationships pertains to the formation of faults and the age of the sequences through which they cut.
Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault.
Possible explanations are offered for the discrepancies, and further experiments are suggested.
The universe is full of naturally occurring radioactive elements.