Topography Study Guide
Summary of the Chapter All landforms are composed of rocks or their weathered by products. Three main types of rocks can be identified on the Earth's surface: igneous, sedimentary and metamorphic.
The rock cycle is a model that describes how various geological processes create, modify and influence rocks. The rock cycle suggests that all rocks originated from magma. This model also suggests that all rock types can be melted back into magma by tectonic forces that return rock to the mantle. Time has a unique meaning to geoscientists.
To a geoscientist time is not measured in seconds, minutes or days, but in eons, eras, periods, and epochs. Each one of these units measures time according to major geologic events that have occurred over the 4.6 billion years of Earth history. When a geoscientist mentions the Cretaceous we know that this is a time period that occurred between 65 to 144 million years ago.
Uniformitarianism is an important theory central to understanding in geology and geomorphology. This theory suggests that the continuing uniformity of existing geomorphic and geologic processes should be used as the intellectual framework for understanding the geologic history of the Earth. It rejects the idea that the landscape of the Earth is the result of catastrophic processes (e.g., the biblical flood). Three types of rocks are recognized by geologists: igneous, sedimentary, and metamorphic. Igneous rocks are formed by the solidification of magma.
This solidification can occur at or beneath the Earth's surface. Sedimentary rocks develop from the lithification of sediments or weather rock debris. Two general categories of sedimentary rocks exist: clastic and non-clastic. Metamorphic rocks are created by the alteration of existing rocks by intense heat or pressure. Most rocks are composed of one or more minerals. The minerals that make up a rock can be produced by magma solidification (igneous rocks), sedimentation of weather rock debris (sedimentary rocks), or metamorphism (metamorphic rocks).
Minerals are naturally occurring inorganic solids that have a crystalline and a unique chemical make-up. Geologists have discovered more than 2000 different types of minerals. The various types of minerals have been classified into nine groups. Igneous rocks are produced by the crystallization of magma.
This process can occur at the Earth's surface or beneath the ground. The type of igneous rocks that forms from solidification is controlled primarily by magma chemistry, temperature of crystallization, and rate of cooling. Four basic types of magma have been classified by geologists. This classification is based on chemistry. Felsic magma contains relatively high quantities of sodium, aluminum, potassium, and silica. Its solidification produces granite, dacite, rhyolite, and granodiorite. Each of these rocks has a unique mineral composition and grain size.
Mafic magma is rich in calcium, iron, magnesium, and relatively poor in silica (between 45 to 52%). The rocks that are created from this magma include basalt and gabbro.
These rocks are dominated by the minerals pyroxene, amphibole, and olivine. Intermediate magma produces andesite and diorite. These rocks contain less silica (between 53 to 65%) and have a chemistry that is between felsic and mafic. Dominant minerals in these rocks include pyroxene, amphibole, and plagioclase feldspars. Ultramafic igneous rocks contain relative low amounts of silica (. Essay Questions (1).
Discuss in detail the formation of sedimentary rocks. Also, include in your answer information concerning their composition, lithification, and naming. Explain why the theory of plate tectonics explains lithospheric phenomena like earthquakes, mountains, volcanoes, folding, and faulting. Compare and contrast the structure, composition, and formation of igneous and sedimentary rocks. Discuss the classification of clastic sedimentary rocks according to particle types. Outline the Bowen reaction series. What does it tell us about the formation of minerals in igneous rocks?
What geologic features are found at the boundaries of tectonic plates? Briefly explain how plate tectonics is responsible for their formation or occurrence. What evidence exists for the theory of plate tectonics (8). Describe the various types of igneous rocks that exist according crystal size, magma chemistry, and the quantity of various mineral types. Discuss how heat, pressure, and the chemical action of fluids act to create metamorphic rocks. Describe some of the common types of metamorphic rocks. What is the difference between clastic and non-clastic sedimentary rocks?
What are the two general types of non-clastic sedimentary rocks that exist? Finally, give two examples of each of these three rock types. What are the eight most common elements found in minerals? Describe the nine major groups of minerals. Describe the various layers that make up the solid Earth.
Describe the various physiological features associated with the ocean basins. What is a volcano? Where and why do they form? Describe the five different types of volcanoes. Describe the various physiological features associated with the Earth's terrestial surface.
Describe the various physiological features associated with the Earth's ocean basins. Outline the various processes of physical, chemical, or biological weathering. Erosion can be seen as three processes: detachment, entrainment and transport. Discuss these three processes in relation to following two erosional mediums: water and ice. Discuss the nature of hillslope failure processes as related to cohesive and non-cohesive materials slope materials.
Topography Study Guide
Describe the physical characteristics of a location that would favor each of the following types of mass movements: rockfall, rockslide, mudflow, slump, and creep. What is a glacier? What conditions are necessary for a glacier to form? Why did continental glaciers form over certain specific regions of the North American continent? Describe the overall impact of extensive alpine glaciation on the mountainous regions of British Columbia. What are some of the more important erosional and depositional landforms?
By what processes do waves and currents erode coasts? Briefly describe each process? What coastal environmental conditions favor coastal erosion? What conditions favor coastal deposition?
How do glaciers influence the surface configuration of the Earth by way of erosion and deposition? Give plenty of examples in your answer. What are some of the common features associated with continental glaciation? How are these features formed?
Typography Study Guide
Briefly describe SIX depositional features associated with continental glaciation. How does beach drift and longshore drift move sediment along coastlines?
What factors often trigger mass movement? Describe the various processes that operate in periglacial regions. Describe the common landforms found in periglacial regions. Describe some of the landforms common to environments influenced by eolian processes. Describe some the important characteristics of soil. What five factors are important in pedogenesis? Outline how the pedogenic processes operate.
Topography Study Guide
Describe the Canadian and US systems of soil classification.