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76 Cards in this Set
- Front
- Back
As seawater evaporates the following sequence of minerals/compounds forms: |
Carbonates, gypsum, halite, Mg- and K-chlorides |
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Today reefs are constructed mostly by corals. Which organisms made reefs prior to corals? |
Rudists |
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Marble is a metamorphic rock that forms from _ |
Limestone |
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Which of the following tectonic settings will be coolest at 30km depth? |
Stable continental lithosphere |
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Which mineral is diagnostic of metamorphism? |
Staurolite |
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Approximately what is the pressure on a rock at 15km depth in the Earth's crust? |
4000 times atmospheric pressure |
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A geothermometer is _ |
A mineral assemblage that reveals the maximum temperature attained by a rock |
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What is the average rate at which temperature increases with depth in the Earth's crust? |
30°C/km |
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Which process(es) will cause metamorphism? |
An increase in Pressure Interaction with hydrothermal fluids An Increase in temperature |
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During metamorphism, changes in the bulk composition of a rock occur primarily as a result of _ |
Reaction with hydrothermal fluids |
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How is general pressure in all directions called (e.g atmospheric pressure) |
Confining pressure |
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What is metasomatism? |
A change in the bulk composition of a rock during metamorphism |
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What is the primary source of the carbon dioxide in metamorpic fluids? |
Sedimentary carbonates |
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What type of metamorphism is caused by high temperature and high pressure imposed over a large volume of crust? |
Regional |
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What type of metamorphism is caused by igneous intrusions? |
Contact metamorphism |
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At what depth does low-grade metamorphism begin? |
6-10 km |
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Where does seafloor metamorphism take place?
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Divergent plate boundaries |
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What is the relationship between metamorphic foliation and sedimentary bedding? |
There is no general angular relationship between sedimentary bedding and metamorphic foliation |
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The parallel alignment of mica in a metamorphic rock is an example of _
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Foliation |
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What type of metamorphic rock was once used to make blackboards because of its ability to split easily into thin sheets along smooth, parallel surfaces? |
Slate |
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Which of the following rocks represents the highest metamorphic grade? |
Gneiss |
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What is not used to classify foliated rocks? |
The texture of the parent rock |
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Which tectonic settings may be characterized by regional, high-pressure and ultra-high-pressure metamorphism? |
Convergent plate boundaries |
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Which of the following statements about the metamorphism of a shale is false?
With increasing metamorphism, 1) clay minerals break down to form micas 2) the grain size of the rock gets smaller 3) foliation develops 4) the amount of water in the rock decreases |
2) With increasing metamorphism, the grain size of the rock gets smaller |
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Order schist, gneiss and slate according to increasing metamorphic grade
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Slate -> Schist -> Gneiss |
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Light-colored rocks with coarse bands of segregated light and dark minerals are called _ |
Gneisses |
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Which of the following metamorphic rocks is incorrectly paired with its parent rock? 1) Greenstone - Basalt 2) Quarzite - Granite 3) Marble - Limestone 4) Schist - Shale |
2) Quartzite - Granite |
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Which metamorphic rock is always foliated? |
Schists |
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Which rock has a granular texture? |
Hornfels |
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Which metamorphic rock forms from mafic volcanic rocks? |
Greenstrone |
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A non-foliated contact metamorphic rock is called a _
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Hornfels |
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Granoblastic metamorphic rocks generally contain minerals that are _ in shape. |
equant |
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Which metamorphic rocks cannot form from a shale? |
Marble |
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What type of metamorphic rock has undergone partial melting? |
Migmatite |
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Which rock can be considered gradational between an igneous and a metamorphic rock? |
Migmatite |
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Which metamorphic minerals commonly form porphyroblasts? |
Garnet |
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What is a porphyroblast? |
A relatively large metamorphic mineral |
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Which rock represents the highest grade of metamorphosed mafic volcanic rocks? |
Granulite |
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What metamorphic facies occurs at temperatures of 400°C and pressures of 6 kilobars? |
Greenschist |
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In the metamorphic map, isograd B is the _ isograd. |
sillimanite |
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What mineral would not be present in the garnet zone? |
Staurolite |
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In which direction is the metamorphic grade increasing? |
East |
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What is the most likely parent rock of a metamorphic rock containing muscovite, biotite, garnet, and quartz? |
Shale |
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Which metamorphic facies represents the highest temperature? 1) Amphibolite 2) Blueschist 3) Granulite 4) Greenschit |
3) Granulite |
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Which pressure-temperature regime represents the eclogite facies? |
Area G |
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Which pressure-temperature regime represents the greenschist facies? |
Area D |
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Under what conditions does zeolite-faceis metamorphism occur? |
Relatively low pressure and low temperature |
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Which mineral is commonly used to determine a metamorphic P-T path? |
Garnet |
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The prograde part of a metamorphic P-T path occurs during _ |
Burial and heating |
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Melanges and blueschists are characteristic of which tectonic setting? |
Subduction zones |
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Which metamorphic rock forms in the forearc of a subduction zone? |
Blueschist |
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What metamorphic rock could also be considered a transitional rock between igneous and metamorphic? |
Migmatite |
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Metamorphic mineral assemblages that can be used as pressure gauges are referred to as _ |
Geobarometers |
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What kind of metamorphism would you expect to see in the rocks at a meteorite impact site? |
Shock |
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Eclogite rocks form during _ metamorphism |
Ultra-high-pressure |
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The parent rock of quartzite is _ |
Sandstone |
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The parent rock(s) of granofels is/are _
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Shale Impure sandstone Granite |
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A metamorphic rock that is described as porphyroblastic has _ |
Large crystals in a fine-grained matrix |
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Different pressure-temperature zones withing a belt of regionally metamorphosed rock are defined by the presence of _ |
Index Minerals |
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Epidote is a common metamorphic mineral found in metamorphised _ |
Basalt |
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What kind of metamorphism would you expect to find at a convergent plate margin?
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Regional high-pressure Contact |
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The process whereby metamorphic rocks rise to the Earth's surface is called _ |
Exhumation |
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The flow of metamorphic rocks back to the Earth's surfcae is controlles by tectonics and _ |
Erosions |
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What type of metamorphic rock is granofels? |
A granulite |
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Which mineral is commonly found as a porphyroblast? |
Staurolite |
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Metamorphic rocks may form from _ |
Any of the major rock types |
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Which metamorphic rock type is most likely to contain visible fossils? |
Marble |
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Metamorphism happens when rocks are subjected to _ |
New temperatures and pressures |
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Metasomatism does not involve a change in _ |
Rock texture |
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What kind of metamorphism would you expect to be pervasive on the lunar surface? |
Shock metamorphism |
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Under what P and T conditions does zeolite-facies metamorphism occur? |
less than 5kbars and 200°C |
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ONe might expect show metamorphism to be more common on the lunar than terrestrial surface because the Moon has _ than Earth |
A less dense atmosphere |
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Geologists have recently linked rapid rates of uplift and exhumantion to _ |
Climate |
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With increasing grade, contact metamorphism would pass which regions? |
A, E, and F |
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With increasing grade, metamorphism in a subduction zone would pass which regions? |
A, D and G |
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Which metamorphic facies would be highly unliekly to occur in a subduction zone |
Granulite |