7: Igneous Rocks
- Page ID
- 29100
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- Explain partial melting and the geological processes that lead to melting.
- Describe the range of chemical compositions of magmas.
- Discuss the processes that take place during magma cooling, and the order of crystallization in Bowen’s reaction series.
- Explain how fractional crystallization and partial melting alter magma composition.
- Classify igneous rocks according to the proportions of minerals within them.
- Describe the origins of aphanitic, phaneritic, and porphyritic textures
- Classify plutons according to their shapes and relationships to surrounding rocks.
- Explain how chilled margins form.
- 7.1: Magma and How It Forms
- This page explains that igneous rocks form from cooled magma, which is primarily composed of elements like oxygen and silicon. The composition of magma is affected by the original rock's makeup and melting conditions, mainly through partial melting, conduction, decompression, or flux-induced melting with added water. These processes are closely related to the dynamics of plate tectonics.
- 7.2: Crystallization of Magma
- This page outlines the rock cycle, focusing on magma formation and crystallization processes. It describes the transition from ultramafic mantle rocks to magma and the factors that change its composition, including Bowen’s reaction series. The classification of igneous rocks into ultramafic, mafic, intermediate, and felsic categories based on silica content is emphasized.
- 7.3: Classification of Igneous Rocks
- This page explains the classification of igneous rocks based on mineral composition and grain size, categorizing them into felsic, intermediate, mafic, and ultramafic types influenced by Bowen’s reaction series. It distinguishes between intrusive and extrusive rocks, describing textures like phaneritic and aphanitic, as well as porphyritic textures indicating varied cooling rates.
- 7.4: Intrusive Igneous Rocks
- This page explains how magma rises due to its lower density compared to surrounding rock, employing mechanisms like filling cracks and melting. It details the formation of xenoliths through stoping and describes how magma cools in the crust as various plutons—stocks, batholiths, dikes, sills, laccoliths, and pipes. The page also highlights the significance of understanding plutons for identifying geological formations, emphasizing the distinct textures created by rapid cooling at margins.
- 7.5: Chapter 7 Summary and Key Term Check
- This page details Chapter 7, which covers the formation, crystallization, classification, and characteristics of igneous rocks. It explains magma formation through processes like decompression and flux-induced melting, and how magma composition influences crystallization according to Bowen's reaction series.