Relative dating exercise 1 Striper chatbot
Applying the principles of relative dating to these rock exposures (also called "outcrops"), we can reconstruct the sequence of events that created the geologic features which we see.
Events can be the deposition of a sedimentary layer, the eruption of a lava flow, the intrusion of magma to form a batholith, a fault (break) in the rock that shifts one side relative to the other side (and causes an earthquake), a fold that bends and distorts rock layers, or any number of other geologic processes.
Also an igneous intrusion is present (labeled T) and a fault is present (labeled A).
Question 3: What is the sequence of events that can be inferred from the above cross-section?
We have seen that a cliff or a road cut is a local "geologic cross-section" -- a side view of the geology at one location.
without knowing the absolute ages at which the rocks themselves formed.
To review our principles of relative dating as applied to such geologic cross-sections, we will make use of a neat learning tool available on the Internet.
"Athro Limited" is a private company which provides education modules on the Internet.
In the same way, such a transect could also show the inferred profile of the geology underfoot -- the expected rock layers and structures beneath the land from the northwest corner to the southeast corner of the map. You can open a larger version of this diagram by clicking on it.
Notice that the various sedimentary layers have been labeled with letters.