Hutton thought that the intermediate rock layers eroded away before the more recent rock layers were deposited.Hutton's discovery was a very important event in geology!Absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. Some other methods are good for archaeological ages.Dendrochronology involves recognizing the sequence of tree rings.In micro paleontological analysis, you may not need the general view if all you are trying to establish is which of two foraminifera is the older.
Rock layers may have another rock cutting across them, like the igneous rock in Figure below. To determine this, we use the law of cross-cutting relationships.
As the environment changes, living creatures adapt. They think about how long it took for those events to happen. The laws of stratigraphy can help scientists understand Earth’s past. Refer to the figure as you read about the laws below.
The laws of stratigraphy are usually credited to a geologist from Denmark named Nicolas Steno. Superposition refers to the position of rock layers and their relative ages.
Relative age means age in comparison with other rocks, either younger or older.
The relative ages of rocks are important for understanding Earth’s history.