Summary

Hopefully, you now have a much greater appreciation for every rock you see. You likely understand the basic types of rocks and how they have developed through the ages. Geological time is very long, so most of the rock to see have a long history dating from billions of years ago.

In this course, you studied rock formation through the diverse actions of the earth's crust, a long history of sedimentation processes, the flow of water and air, and the heat of fire – and many more processes that shape every rock, river, and valley you encounter in everyday life. You now know why the study of geology is important, even if this is not your college major.

Chapter one introduced the basic terminology you needed to know to get started in the subject of geology. Geology is one of those courses where there is a lot of lingo to learn in order to even get started. This chapter simply got you started on your geology adventure. You also learned about the 3 basic types of rocks and how they come to be rocks in the first place.

Chapter two began our discussion of planet earth and its many unique features by looking directly at its origins. You learned that the earth is about 4.54 billion years old and began as a giant cloud of swirling space dust. Boy, has it changed! We looked at how all that dust collected into the wide range of rocks, minerals, and amazing geological structures on land and sea we now research in geology. At the end of the chapter, you studied the continental features and seafloor landscape and why they exist as they do now.

Chapter three allowed you to examine the concept of geologic time. As you know, this timeframe dates back to the first days when the earth's crust was being developed. Older rocks look different from younger rocks; you needed to know the difference between them. You learned how to date rocks and how you can use rocks to indicate the age of

fossils. The chapter also looked at the different types of fascinating fossils you can find in your own back yard or nearby rock quarry.

Chapter four involved a discussion of what we know about plate tectonics. You learned that it is still called "plate tectonic theory" even though there aren't any legitimate counter-theories on why the continents exist at all and where they are located. You also saw what plate tectonics means for geologists. Clearly, the earth is still changing and phenomena like earthquakes and mountain-building can be easily explained by understanding how the lithosphere moves on this planet.

Chapter five in the course finally began to talk about what many people think geology is all about – cool rocks and minerals. You saw that a mineral is a hardened substance from the earth that is made from single element or just a few elements in a chemical compound. The two main mineral classifications you learned about are the silicates and non-silicates. You studied how to classify and identify the most common minerals you'll find around the world and even in your own backyard.

Finally, we got into detail on the subject of igneous rocks and their formation in Chapter six of the course. You learned that igneous rocks are literally born out of fire –the first rocks to be spit out of our molten interior. After reading this chapter, you could see all of the stuff that's in magma and how it turns into the rocks you see all the time. Magma is more than just underground lava. You were able to study and learn about the amazing things that happen when it cools and the ways the minerals precipitate out of it when that occurs.

Chapter seven delved into volcanism and the volcanoes we have on earth. Volcanoes help dispel the heat from inside our planet and contribute to new land formation in some parts of the world. You learned just how magma is extruded from deep within the earth through volcanic activity. You already knew that lava is just surface magma but soon learned that there are several types of volcanoes and volcanic eruptions all over the world. We also discussed how volcanic eruptions might be predicted.

Chapter eight in the course covered weathering and its effects on geology. Weathering is inevitable and can change rock faces for many reasons. You learned how these work with regard to sedimentary rocks and how weathering creates soil. You saw how soil is

different all over the world for many reasons. You also studied how soil forms and what makes each soil type unique. Weathering can create ore deposits, as you also learned.

Chapter nine allowed you to finally learn about sedimentary rocks. You saw that if igneous rocks are basically the primary rocks, then sedimentary rocks are secondary. These are the rocks that start out as smaller pieces called sediments, becoming lithified to form their own kind of stone. You learned how to name sedimentary rocks and what we gain economically from products these types of rocks provide us on earth.

Chapter ten in the course rounded out the discussion of rock types by revealing how we get metamorphic rock. Things, pressure and heat cause metamorphic change in rocks, leading to many different rock types. You now fully understand the complexities of metamorphism and how they lead to several types of new rock from old rock.

Chapter eleven in the course is about earthquakes. Studying earthquakes reminds us that geology isn't just about rocks. You learned in this chapter that earthquakes are perhaps the best proof that plate tectonics is not theoretical. They happen mainly when two or more plates are moving in directions that are not congruent with one another. You also learned how earthquakes are measured and saw why they cause so much damage.

Chapter twelve taught you how and why rocks deform. You saw that while rocks seem so solid, the awesome powers of earth movement can still create giant mountains and crush sedimentary rock into much harder metamorphic rock. You hopefully learned the patterns of rock deformation and understood the types of stress the earth's crust is under on a daily basis. The chapter helped you understand why the earth has the interesting topography it has now and why it will probably continue to have even more interesting and different topography in the future.

Chapter thirteen in the course helped you understand better the geological phenomena seen due to the effects of gravity. You were reminded that gravity pulls everything toward the center of the earth so that heavy things that don't have the necessary friction or infrastructure to hold up properly will fall down. Rock, dirt, sediment, snow, and ice all participate in this process to create things like landslides,

mudslides, flows, and even avalanches. You also saw that there are more forces at play in these gravity-based situations besides the law of gravity.

Chapter fourteen was a study of water; you learned that it is important to study water in geology because water shapes geologic structures to a huge degree. Water is contained in the hydrosphere but it interacts with the geosphere all over the world. You learned about streams, rivers, deltas, and basins and why they are such critical parts of the geology of the earth.

Chapter fifteen in the course covered glaciers and how they shaped the geomorphology of the earth. You now know that glaciers represent the cryosphere of the earth and that, while there are more or fewer of them at any given point in time, glaciers still exist today in pockets all over the earth. You also saw just how important glaciers have been in shaping the land and water features in all of the continents of this planet in so many ways.

After studying geology as a science with a lot of different features to consider in this course, rocks now likely take on a new meaning to you. While you may not be able to name every rock you pick up off the ground, you probably can understand in a new light how it came to look the way it does. Who knows? You may have decided to make geology a topic you want to study further.

Good luck!