19: Geology of the Oceans
- Page ID
- 29182
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- Describe the origins of the major topographic features of the sea floor, including continental shelves and slopes, spreading ridges, seamount chains and isolated seamounts, and deep submarine canyons.
- Describe the various components of oceanic crust: pillow basalts, sheeted dikes, gabbro bodies, layered gabbro, and layered ultramafic rock.
- Describe the age distribution of oceanic crust and explain why all of it is relatively young.
- Summarize the types of sediments and sedimentary rocks that accumulate on the sea floor and explain why different types of sediment are present in different areas.
- Explain the origins of sea-floor methane hydrates.
- Describe and explain regional variations in the salinity and temperature of ocean water.
- Describe the general nature of major ocean-surface currents and the origins of deep-ocean circulation patterns.
- Explain the importance of ocean currents to our climate.
- 19.1: The Topography of the Sea Floor
- This page explores ocean bathymetry, highlighting the Atlantic and Pacific Ocean floor features such as continental shelves, abyssal plains, mid-ocean ridges, and deep trenches with depths over 11,000 meters.
- 19.2: The Geology of the Oceanic Crust
- This page explores oceanic crust formation, emphasizing its origin from magma at sea-floor spreading ridges and subsequent geological evolution. It details the composition of oceanic crust, mainly from mafic magma, leading to rock types like pillow basalts and gabbro, and notes the age variation, with the oldest sections being roughly 280 million years old.
- 19.3: Sea-Floor Sediments
- This page discusses the composition of the sea floor, highlighting the various sediment types such as terrigenous, pelagic carbonate, pelagic silica, volcanic ash, and iron/manganese nodules. It notes that sediment characteristics depend on factors like continental proximity and water depth. Terrigenous sediments are typically found near coasts, while carbonate sediments form from marine life and are absent below 4,000 meters.
- 19.4: Ocean Water
- This page discusses the salinity of seawater, which is mainly due to dissolved ions from rivers and varies regionally based on evaporation and freshwater input. Ocean salinity averages 35 g/L and is highest in dry regions like the Mediterranean. It explains the importance of thermohaline circulation for global heat transfer and potential climate impacts from its slowdown.
- 19.5: Chapter 19 Summary
- This page discusses ocean floor topography, including continental shelves and seamounts, and covers oceanic crust formation with basaltic structures and volcanic activity. It highlights the age of the crust, sea-floor sediment variations, and the influence of biological activity on composition. Additionally, it examines properties of ocean water, such as salinity and temperature, and emphasizes the importance of ocean currents in global heat distribution and climate effects.