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Geology 100--General Geology

Exam No. 1 Study Guide

Discuss three important characteristics of a scientific theory.  Briefly describe the "scientific method."  What distinguishes science from other fields of knowledge? 

What are Earth's principal compositional layers?  How do these layers differ in terms of chemical composition and density?  How do continental and oceanic crust differ in terms of density and composition? What elements is each Earth layer enriched in?  

Summarize the theory of plate tectonics.  Distinguish between the lithosphere and asthenosphere.  Be able to describe the relative motion of two plates at various types of plate boundaries, including subduction zones, collision zones, transform boundaries, and divergent boundaries.  Be able to summarize, in detail, the evidence that supports the theory of plate tectonics.  What processes are thought to drive plate motions? 

What defining characteristics do all minerals possess?  Be able to explain how the basic chemical building block of the silicate minerals—the silicate tetrahedron--is put together.  What is the chemical formula for this structure?  Why is the large negative of this structure important?   Be able to explain the silicate structure (e.g., isolated tetrahedra, single chains, double chains, sheets, 3-D framework, etc.) of each of these minerals: olivine, pyroxene, amphibole, biotite/muscovite, quartz, plagioclase feldspar (plag), potassium feldspar (K-spar). Understand the difference between the ferromagnesian and non-ferromagnesian silicate minerals in terms of composition.  Be able to describe some important mineral properties used to identify common minerals in hand specimen.    

What is the order of crystallization (in terms of temperature) of various minerals from a mafic magma as predicted by Bowen's Reaction Series?  Explain the different ways that magmas can change composition.  How are magmas classified?  What, besides temperature, affects melting and crystallization?  What are the intrusive/extrusive equivalents for igneous rocks of felsic, intermediate, and mafic composition?  

Know the factors that affect the eruptive style of a volcano. What is the basic textural difference between plutonic and volcanic rocks in terms of crystal size?  What are the different igneous rock textures and what do they tell us about the cooling histories of igneous rocks? 

Understand the differences between various volcanic landforms, including shield volcanoes, cinder cones, and stratovolcanoes.  Which type of volcano is most common at subduction zones?  Which type is most explosive?  Which types are associated with mafic magma?  Which type is associated with intermediate magma?  

Be able to distinguish between the two main types of weathering. List several examples each of mechanical and chemical weathering processes.  Be able to explain how susceptibility to chemical weathering relates to Bowen’s Reaction Series.  Be able to explain how mechanical and chemical weathering act together (i.e., reinforce each other) to disintegrate and decompose a rock mass.  Which type of weathering predominates in arid environments? In humid environments?  

Important Vocabulary...