Learning about sedimentary rock is made easy when you read the basics of sedimentary rocks set out in this article.
1Understand how sedimentary rocks are made. Existing rocks are eroded mainly by water or ice, deposited in rivers, lakes and oceans. When these particles are dropped they build up gradually in layer upon layer. Over millions of years these sediments are buried deeply and are exposed to pressure and temperature turning soft sediment to rock. Collisions of continents and other forces bring these rocks to surface; are exposed and the cycle begins again.Ad
2Be aware of the different types of sedimentary rocks:
- Coal - coal is formed from layers of dead vegetation, such as trees and plants that were laid down in a swamp, buried deeply where pressure and temperature concentrates the carbon in the plant cells forming coal.
- A conglomerate - a conglomerate is a sedimentary rock that is composed of particles of varying size and shape, such as small, medium and large round pebbles mixed with small sand grains.
- Limestone - limestone is composed of calcium carbonate derived from the exoskeletons of sea life such as corals and shelled animals, it can also be precipitated by sea grasses. Lime mud and lime debris are deposited along coastlines. These are buried and slowly recrystallize into limestone.
- This image shows the sea creatures encrusted within limestone.
3Recognise that this article provides only a very basic overview of sedimentary rocks. The most important thing to remember about sedimentary rocks is that they record the long history of our planet.Ad
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- When you go on vacation and visit the coast, fossil areas and other geologically interesting places, take time out to investigate the rocks around you. You may even live close to sedimentary rock formations; see if you can locate them and take photos for a project.
Sources and Citations
- VideoJug. A movie explaining sedimentary rock formation and content. Original source of article - acknowledgment to geology expert, Dr. Matt Genge. Shared with permission and appreciation.