3 rock types
Most of the rocks on the earth's surface is of the sedimentary kind and this also happens to be the one most interesting to hydrocarbon exploration.
1 - Igneous rocks are "fired formed" and come from deep within the earth, i.e. volcanoes. When a volcano spits up magma to the surface and it cools, the rock is igneous. Common igneous rocks are basalt and granite. When you are in an area that has lots of igneous rocks and you can deduce there was a high chance the area had volcanic activity at some point in earth's history.
2 - Metamorphic rocks are those that have been altered via extreme heat and pressure. Tectonic activity causes causes intense stress and pressure on rocks causing it to under go physical and chemical changes. Marble is an example of a metamorphic rock. When the sedimentary rock limestone experiences extreme heat and pressure, it changes to become the metamorphic rock marble.
3 - Sedimentary rocks are the Frankenstein of rocks because it is made from the redeposition of eroded material from existing rocks. When rocks are exposed to the elements of nature, they become weathered and eventually grains from these weathered rocks get transported by rivers and streams and eventually to oceans. The deposition of these sediments on the ground over time leads to lithification.
Lithification
Process where unconsolidated sediments become a sedimentary rock by compaction and cementation. As deposition occurs, older sediments are buried deeper and deeper. This increasing overburden squeezes out water, compacting the sediments until individual particles come into contact. Cementation by calcium carbonate or silica precipitation from circulating waters may glue the rock grains together.
Continental drift
The continents are moving and the earth at one point was a single continent. This is because the earth acts as a giant convection cell where hot rocks move away from the center of the earth cool, and Earth as a layer cake
Crust
Mantle
Outer core
Inner core
Geologic Structures
Folding
Faulting
