This text is designed to give you a comprehensive introduction to Geology at no or very nominal cost. It contains both written and graphic text material, intra-text links to other internal material which may aid in understanding topics and concepts, intra-text links to the appendices and glossary for tables and definitions of words, and extra-text links to videos and web material that clarifies and augments topics and concepts.
- Metamorphic rocks is one of the three rock categories in the rock cycle. Metamorphic rock material has been changed by temperature, pressure, and/or fluids. The rock cycle shows that both igneous and sedimentary rocks can become metamorphic rocks. And metamorphic rocks themselves can be re-metamorphosed. Because metamorphism is caused by plate tectonic motion, metamorphic rock provides geologists with a history book of how past tectonic processes shaped our planet
- Sedimentary rock and the processes that create it, which include weathering, erosion, and lithification, are an integral part of understanding Earth Science. This is because the majority of the Earth’s surface is made up of sedimentary rocks and their common predecessor, sediments. Even though sedimentary rocks can form in drastically different ways, their origin and creation have one thing in common, water.
- This chapter discusses the fundamental processes driving mass-wasting, types of mass wasting, examples and lessons learned from famous mass-wasting events, how mass wasting can be predicted, and how people can be protected from this potential hazard. Mass wasting is the downhill movement of rock and soil material due to gravity. The term landslide is often used as a synonym for mass wasting, but mass wasting is a much broader term referring to all movement downslope.
- The hydrosphere, liquid water, is the single most important agent of erosion and deposition. The cryosphere, the solid state of water in the form of ice also has its own unique erosional and depositional features. Large accumulations of year-round ice on the land surface are called glaciers. Masses of ice floating on the ocean as sea ice or icebergs are not glaciers, although they may have had their origin in glaciers.
- This chapter describes the systems involved in regulating Earth’s temperature, its climate, geologic evidence of past climate changes, and the role humans have on today’s climate change. It is critically important to be aware of the geologic context of climate change processes if we want to understand anthropogenic (human-caused) climate change.
- Coastlines are the great interface between the 29% of earth’s surface that is land and 71% of earth that is covered by the oceans. Therefore, it is the longest visible boundary on earth. To understand the processes that take place at this interface, we must first consider the energetic action at this boundary; namely, waves. The importance of this interface is seen in the study of ancient shorelines, and particularly for natural resources, a process called sequence stratigraphy.
- Approximately 30 percent of Earth’s terrestrial surface is desert. Deserts are defined as locations of low precipitation. While temperature extremes are often associated with deserts, they do not define them. The lack of moisture, including the lack of humidity and cloud cover, allow temperature extremes to occur. The sun’s energy is more absorbed by the Earth’s surface without cloud cover, and nighttime cooling is more drastic without cloud cover and humidity to absorb the emitted heat, so temp
- An important use of geologic knowledge is locating economically valuable materials for use in society. All items we use can come from only three sources: they can be farmed, hunted or fished, or they can be mined. without mining, modern civilization would not exist. Geologists are essential in the process of mining.