Question

Provide two examples of things that apply to both relative and absolute dating.

Answer 1

Relative dating 
1) The law of superposition states that, in an undisturbed stratigraphic environment, the oldest layers of strata are beneath the younger ones. 

2) The law of original horizontality states that layers, when originally deposited, are fairly horizontal; folds and tilted beds are consequences of deformation that post-dates deposits. 

3) The law of original continuity states that sedimentary layers generally accumulate in continuous sheets. 

4) The law of cross-cutting relations states that cutting features are younger than the cut strata. 

5) The principle of baked contacts states that igneous intrusions metamorphose surrounding rock, and the metamorphosed rock is older than the intrusion. 

6) The principle of inclusions states that, if a layer of sediment over an igneous layer includes pebbles of the igneous rock, then the sediment is younger. 

Absolute dating 
1) Radioactive isotopes are unstable and decay at a constant rate, allowing geochronologists to determine a numerical age. Radiocarbon dating is used to date organic remains. 

2) Rate of tree growth, shell growth, and production of other organic material 

3) Rate of snow accumulation, clastic sediment deposition, and chemical sediment precipitation