Plate Boundary Features Chart

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    Mar, 1999
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   Mar 1, 2006
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PLATE BOUNDARY FEATURES CHART

The lithosphere of our planet made of large masses of rock called plates. These plates move. Features form at the edges of the plates from the activity that occurs at these plate boundaries.

Below is a summary graphic of the features that form at each type of plate boundary. As you learn about plate tectonics, fill in the names of examples of each of these features.

C/O stands for Continent to Ocean, C/C is Continent to Continent, O/O is ocean to Ocean. If the graphics look strange when you first load this page, try "reload" or "refresh".

FEATURE/
ACTIVITY 		DIVERGE C/O
CONVERGE 		C/C
CONVERGE 		O/O
CONVERGE 		TRANS
VERSE
PLATE DIRECTION apart toward
each
other 		toward
each
other 		toward
each
other 		past
each
other
EARTH-
QUAKES

Earthquakes occur at all plate boundaries Earthquakes occur at all plate boundaries Earthquakes occur at all plate boundaries Earthquakes occur at all plate boundaries Earthquakes occur at all plate boundaries
VOLCANOES


At divergent boundaries such as the Mid-Atlantic Ridge, new thin oceanic type basaltic crust is formed from molten rock that fills in the gap between plates Oceanic-continental convergence also sustains many of the Earth's active volcanoes, such as those in the Andes and the Cascade Range in the Pacific Northwest. . Subduction processes in oceanic-oceanic plate convergence also result in the formation of volcanoes. Over millions of years, the erupted lava and volcanic debris pile up on the ocean floor until a submarine volcano rises above sea level to form an island volcano. .
MOUNTAIN
RANGES

. The oceanic Nazca Plate is pushing into the continental part of the South American Plate. In turn, the overriding South American Plate is being lifted up, creating the towering Andes mountains, the backbone of the continent When two continents meet head-on, neither is subducted because the continental rocks are relatively light and, like two colliding icebergs, resist downward motion. Instead, the crust tends to buckle and be pushed upward or sideways. The collision of India into Asia 50 million years ago caused the Eurasian Plate to crumple up and override the Indian Plate. After the collision, the slow continuous convergence of the two plates over millions of years pushed up the Himalayas and the Tibetan Plateau to their present heights. . .
FEATURE/
ACTIVITY 		DIVERGE C/O
CONVERGE 		C/C
CONVERGE 		O/O
CONVERGE 		TRANS-
FAULT
ISLAND
ARC

. . . Subduction processes in oceanic-oceanic plate convergence result in the formation of volcanoes. Over millions of years, the erupted lava and volcanic debris pile up on the ocean floor until a submarine volcano rises above sea level to form an island volcano. Such volcanoes are typically strung out in chains called island arcs. As the name implies, volcanic island arcs, which closely parallel the trenches, are generally curved. The trenches are the key to understanding how island arcs such as the Marianas and the Aleutian Islands have formed and why they experience numerous strong earthquakes. .
MIDOCEAN
RIDGE

The mid-Atlantic Ridge, a topographically high area near the middle of the Atlantic Ocean, is an example of a divergent plate boundary. . . . .
SUBDUCTION
ZONE

. Even though the Nazca Plate as a whole is sinking smoothly and continuously into the trench, the deepest part of the subducting plate breaks into smaller pieces that become locked in place for long periods of time before suddenly moving to generate large earthquakes. Such earthquakes are often accompanied by uplift of the land by as much as a few meters. . Magmas that form island arcs are produced by the partial melting of the descending plate and/or the overlying oceanic lithosphere. The descending plate also provides a source of stress as the two plates interact, leading to frequent moderate to strong earthquakes. .
FEATURE/
ACTIVITY 		DIVERGE C/O
CONVERGE 		C/C
CONVERGE 		O/O
CONVERGE 		TRANS-
FAULT
DEEP
SEA
TRENCH

. Off the coast of South America along the Peru-Chile trench, the oceanic Nazca Plate is pushing into and being subducted under the continental part of the South American Plate. . When two oceanic plates converge, one is usually subducted under the other, and in the process a trench is formed. The Marianas Trench (paralleling the Mariana Islands), for example, marks where the fast-moving Pacific Plate converges against the slower moving Philippine Plate. The Challenger Deep, at the southern end of the Marianas Trench, plunges deeper into the Earth's interior (nearly 11,000 m) than Mount Everest, the world's tallest mountain, rises above sea level (about 8,854 m). .
RIFT
ZONE

The consequences of plate movement are easy to see around Krafla Volcano, in the northeastern part of Iceland. Here, existing ground cracks have widened and new ones appear every few months. From 1975 to 1984, numerous episodes of rifting (surface cracking) took place along the Krafla fissure zone. Some of these rifting events were accompanied by volcanic activity; the ground would gradually rise 1-2 m before abruptly dropping, signalling an impending eruption. Between 1975 and 1984, the displacements caused by rifting totalled about 7 m. . . . .
      
Thanks to Volcano world (http://volcano.und.nodak.edu/learning.html) for Rocky The Volcano, and for some of the text that pops up when you move your cursor over Rocky. Thanks to the USGS for most of the text that pops up when you move your cursor over Rocky. This text was found in the USGS document "Understanding Plate Motions" at http://pubs.usgs.gov/publications/text/understanding.html.

More information, including animations, can be found at: http:// www2.nature.nps.gov/ grd/ usgsnps/ animate/ pltecan.html, http:// www.seismo.unr.edu/ ftp/ pub/ louie/ class/ 100/ plate-tectonics.html, http:// volcano.und.nodak.edu/ vwdocs/ vwlessons/ lessons/ Plates/ Plates1.html, http:// library.thinkquest.org/ 17701/ high/ , http:// unix.utb.edu/ %7Epaullgj/ geog1303/ Plate_Tectonics.html , http:// www.pbs.org/ wgbh/ aso/ tryit/ tectonics/ transform.html , http:// www.scotese.com/ indianim.htm .
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