The Rock Cycle

​It shows how the basic rock types are related and how Earth processes, over geologic time, change a rock from one type into another.

​What is rock cycle?

Driving force of rock cycle:

​Earth's internal heat, which causes plate tectonics. The hydrological cycle– movement of water, ice, and air at the surface.

​As the two masses meet, tremendous compressional forces distort and modify the rocks involved. 

Acidic soil water and groundwater is effective at dissolving water minerals and rocks.

Running water carries vast amount of sediment in rivers back to the ocean and inland basin.

​LITHIFICATION

​Is the process by which clay, sand, and other sediments on the bottom of the ocean or other bodies of water are slowly compacted into rocks from the weight of overlying sediments.

​Weathering vs. Erosion

​Weathering is the breaking down or dissolving of rocks and minerals on Earths surface. Once a rock has been broken down, a process called erosion transports the bits of rock and minerals away. Water, acids, salt, plants, animals, and changes in temperature are all agents of weathering and erosion.

Mechanical weathering happens when rock is broken through the force of another substance on the rock such as ice, running water, wind, rapid heating/cooling, or plant growth. Chemical weathering occurs when reactions between rock and another substance dissolve the rock, causing parts of it to fall away.

Frost wedging - in which cracks in rock or other surfaces is filled with water, freeze and expand, causing the cracks to enlarge and eventually break.

Mechanical weathering

Mass wasting - transfer or movement of rock or soil down slope primarily by gravity.

Abrasion - scraping of materials as the sediments are being transported by water or wind.

Mechanical weathering

• Frost wedging

• ​Biological activity

• ​Salt crystal growth

• ​Mass wasting

• ​Abrasion

chemical weathering

Hydrolysis occurs when water dissolves minerals in a rock, producing new compounds.

Example: Feldspar crystals inside the granite react chemically, forming clay minerals.

Carbonic acid also interacts with calcites in caves, causing them to dissolve. Calcite in dripping water builds up over many years to create stalagmites and stalactites.

​Concept Mastery

​Answer letter A and B on pp. 44-45