Ch13_Outline

Ch13_Outline - Chapter 13 Divergent Boundaries: Origin and...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 13 Divergent Boundaries: Origin and Evolution of the Ocean Floor Mapping the ocean floor ± Depth was originally measured by lowering weighted lines overboard ± Echo sounder (also referred to as sonar ) Invented in the 1920s Primary instrument for measuring depth Reflects sound from ocean floor Mapping the ocean floor ± Multibeam sonar Employs an array of sound sources and listening devices Obtains a profile of a narrow strip of seafloor
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Mapping the ocean floor ± Viewing the ocean floor from space Satellites use radar altimeters to measure subtle differences of the ocean surface Small variations reflect the gravitational pull of features on the seafloor Mapping the ocean floor ± Three major provinces of the ocean floor Continental margins Deep-ocean basins Oceanic (mid-ocean) ridges Echo sounder (A) and multibeam sonar (B) Figure 13.3
Background image of page 2
3 Major topographic divisions of the north Atlantic Ocean Figure 13.6 Continental margins ± Passive continental margins Found along most coastal areas that surround the Atlantic ocean Not associated with plate boundaries Experience little volcanism and few earthquakes Continental margins ± Features comprising a passive continental margin Continental shelf Flooded extension of the continent Varies greatly in width Gently sloping Contains important mineral deposits Some areas are mantled by extensive glacial deposits
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Continental margins ± Features comprising a passive continental margin Continental slope Marks the seaward edge of the continental shelf Relatively steep structure Boundary between continental crust and oceanic crust Continental margins ± Features comprising a passive continental margin Continental rise Found in regions where trenches are absent Continental slope merges into a more gradual incline – the continental rise Thick accumulation of sediment At the base of the continental slope turbidity currents deposit sediment that forms deep-sea fans Provinces of a passive continental margin Figure 13.7
Background image of page 4
5 Continental margins ± Active continental margins Continental slope descends abruptly into a deep-ocean trench Located primarily around the Pacific Ocean Accumulations of deformed sediment and scraps of ocean crust form accretionary wedges Active continental margin Figure 13.8 Features of the deep-ocean basin ± Deep-ocean trench Long, relatively narrow features Deepest parts of ocean Most are located in the Pacific Ocean Sites where moving lithospheric plates plunge into the mantle Associated with volcanic activity
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Earth’s deep-ocean trenches Figure 13.9 Features of the deep-ocean basin ± Abyssal plains Likely the most level places on Earth
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 07/17/2008 for the course GS 121 taught by Professor Leavell during the Fall '07 term at Ohio State.

Page1 / 17

Ch13_Outline - Chapter 13 Divergent Boundaries: Origin and...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online