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44 Cards in this Set
- Front
- Back
Which rock layers dating from the Appalachian orogeny consist of North American continental shelf strata deposited prior to the late Paleozoic collision with Africa? |
Folded sedimentary rocks of the Valley and Ridge Province. |
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Mountain belts form from _____ or ______ processes over millions of years. (geosphere) |
volcanic or tectonic |
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Mountain belts ______ as they grow higher and steeper. (hydrosphere) |
erode |
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Mountain belts cause ______ as air rises above them. (atmosphere) |
precipitation |
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The North American Cordillera extends from _____ to _____. |
Alaska Panama |
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What are the stages of mountain belt creation? |
accumulation stage orogenic stage |
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What is the process that collectively produces a mountain belt? |
Orogenesis |
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Which stage of mountain belt formation has rocks (sedimentary) that will later be uplifted, faulted, and folded into |
accumulation stage |
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Which stage of mountain belt formation is a mountain building episode from plate convergence? |
orogenic stage |
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Topographically high-standing mountainous areas are generally underlain by ________. |
greater-than-average thickness of lower-density crustal rocks. |
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What best characterizes the tectonic development of fault-block mountains? |
Normal faults; crustal stretching and brittle failure of the upper crust
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What term describes the zone where two continents collide, often preserving slivers of oceanic lithosphere between the colliding plates? |
Suture |
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What type of basin is characterized by thick sequences of relatively undeformed sedimentary rocks? |
forearc |
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What type of rocks dominate the Valley and Ridge Province of the Appalachian Mountains of North America? |
Sedimentary strata folded in late Paleozoic time. |
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What North American mountains are a geologically old mountain range that was folded and deformed during the Paleozoic? |
The Appalachians in the eastern US. |
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Fault-block mountains are produced when ________ occurs and _________ stretch and thin the brittle upper crust (lithosphere), resulting in upwelling of ________. |
continental rifting tensional forces hot mantle rock |
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The East Coast of the United States provides a modern example of a _______ where sedimentation has produced a thick platform of shallow-water sandstones, limestones, and shales. |
passive continental margin |
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______ is used to describe a crustal fragment consisting of a distinct and recognizable series of rock formations that have been transported by plate-tectonic processes. |
terrane |
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The major features of subduction zones are ______? (List 4) |
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What is the name of a thick accumulation of sediments and small, tectonic blocks formed of material scraped off a descending lithospheric plate? |
Accretionary-wedge complex |
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What concept shows that rocks of the crust and upper mantle are floating in gravitational balance? |
Isostasy |
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What types of rocks make up the cores of the ranges of the central and southern Rocky Mountains? |
Uplifted blocks that typically have cores of Proterozoic igneous and metamorphic rocks |
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Which forces create backarc regions? |
Extension |
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How were the Ural Mountains (in Russia) formed? |
Marine strata in a basin between the former Asian and European plates were squeezed, folded, and uplifted as the two plates joined to form the Eurasian plate. |
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What types of materials are characteristic of volcanism along a continental arc? |
Andesitic lavas and pyroclastic materials |
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What happens to create an accretionary wedge? |
The edge of the overriding plate faces a subduction zone. |
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What is an example of an isostatic movement? |
Uplift of areas recently covered by thick continental ice sheets |
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An ________ is a section of the Earth’s oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often thrust onto continental crustal rocks. |
ophiolite |
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What does the term orogenesis mean? |
The combination of processes that produce mountain belts. |
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Along what type of plate boundaries are most continental mountains formed? |
Convergent |
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At what type of plate boundary would Andean-type subduction zones occur? |
Oceanic-continental convergent? |
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Where does most volcanic activity occur in Andean-type subduction zones? |
Inland on the continent |
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Why is the area around Hudson Bay in northern Canada currently rising? |
Melting of the glaciers made this area lighter, so it is rebounding. |
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What term refers to the fact that the crust "floats" in gravitational balance on a denser mantle? |
Isostasy |
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What two kinds of things can happen at subduction zones? (which crust goes under which) |
Ocean crust under continental crust Ocean crust under ocean crust |
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Which of the following is a large igneous body of rock that results from coalescing plutons in an "Andean-type" margin? |
Batholith |
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What term is applied to the juncture of two continents? |
Suture |
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What describes the "microcontinents" idea for continental collision? |
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What are the components of an accretionary wedge? |
Mud, ash, and sediment from both the volcanic mountains and the top of the subducting slab. |
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Under what circumstances will subduction lead to continental collision, causing it to end? |
A subducting plate may carry a low-density continent that eventually ends up at the trench. Because the continental crust will not subduct, it blocks the subduction zone. |
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What two characteristics do geologists use to recognize ancient continental collision zones? |
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What geologic phenomenon causes South Africa to be elevated by as much as 1500 meters (4950 feet)? |
Hot large superplume in the mantle |
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How is terrane different from terrain? |
Terrane - applies to crustal fragments consisting of distinct and recognizable series of rock formations that have been transported by plate tectonics. Terrain - describes the surface topography. |
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Why was the continental crust of Asia deformed more than India proper during the collision of the two continents? |
India is a continental shield of ancient Precambrian rocks that are over 2 billion years old. Southeast Asia was an accreted region formed from the collision of several small crustal fragments and is still relatively "warm and weak." |