How are metamorphic rocks formed? Metamorphic rocks form from taking a pre-existing rock and increasing the pressure and temperature of the rock changing the rock In metamorphic high temperature and pressure cause both _______ and _________ changes. Physical; chemical Typically with metamorphic rocks occurs ______ km below the surface at temperatures around ________. a) 10-30 km; 200-600°C b) 20-40 km; 200-600°C c) 10-30 km; 100-500°C d) 20-40 km; 100-500°C a) 10-30 km; 200-600°C What are the factors that influence metamorphic changes? Temperature Pressure; both lithostatic and differential pressure Fluid activity How does temperature influence metamorphic changes? Temperatures causes recrystallization and speeds up reactions meaning the bonds rapidly break and reform causing a bigger rock sometimes How does pressure influence metamorphic changes? There are 2 types of pressures that influence metamorphic changes lithostatic pressure and differential pressure. Differential pressure results in the development of foliation How does Fluid activity influence metamorphic changes? Fluid activity may introduce new chemicals and change the rocks bulk composition; speeding up reactions Under dry conditions, most minerals react very _____, but when even small amounts of fluid are introduced, reaction rates ____ with metamorphic rocks. a) slowly; increase b) fast; increase c) slowly; decrease d) fast; decrease a) slowly; increase Define recrystalization Recrystalization is the metamorphic process that occurs under situations of intense temperature & pressure where grains molecules or atoms of a rock or mineral are packed closer together creating a new crystal structure. Define lithostaic pressure Lithostatic pressure is the pressure exerted on rocks by the weight of overylying rocks Define differential pressure Differential pressure is the pressure that is not applied equally to all sides of a rock body Define foliation Foliation is the processes of being split into thin sheets is the result of differential pressure Name the types of metamorphism Regional metamorphism  contact metamorphism burial metamorphism  hydro-thermal metamorphism cataclysmic metamorphism What is regional metamorphism? Regional metamorphism affects the rocks in a large region of the crust, e.g. areas undergoing mountain building (most commonly at convergent boundaries) tends to produce foliated rocks metamorphic grade varies depending on P,T What is contact metamorphism? Contact metamorphism is the heating of rocks adjacent to igneous intrusions  due to heat from magma (not a place to find foliation) What is burial metamorphism? Burial metamorphism affects rocks deep  in sedimentary basins and is low grade metamorphism due to the deep burial of sediments results from high lithostatic pressure Shallow marine setting after millions of years--Fossils can get preserved What is hydro-thermal metamorphism? Hydro-thermal metamorphism resluts from hot, watery fluids altering rock; important at mid-ocean ridges What is cataclysmic metamorphism (dynamic)? Cataclysmic metamorphism (dynamic) results from high pressure alterations along faults producing mylonites *suffered intense pressures Name  the foliated metamorphic rocks slate phylite schist gneiss ampibolite migmatite Name the nonfoliated metamorphic rocks marble quatzite greenstone hornfels anthracite Metamorphic rocks are formed at/in the ______. a) crust b) surface c) mantle d) core a) crust True or False; If false restate to be true Depending on the setting of the metamorphic rock may look different True Name a foliated low grade metamorphic rock that is fine grained and has flat breakage (slaty cleavage) a) slate b) phyllite c) hornfels d) gneiss a) slate Name a foliated low grade metamorphic rock that is fine grained, and has satin sheen a) marble b) phyllite c) schist d) anthracite coal b) phyllite Name a foliated intermediate grade metamorphic rock that is course grained, and has an alignment of platy/elongate minerals a) slate b) quartzite c) schist d) hornfels c) schist Name a foliated metamorphic rock that is high grade metamorphic that is course grained and banded in appearance a) slate b) marble c) anthracite coal d) gneiss d) gneiss Name a non foliated metamorphic rock that is composed of dominant quartz mineral and forms from metamorphosing Sandstone (SS) prolitith. a) slate b) Phyllite c) quartzite d) marble c) quartzite Name a non foliated metamorphic rock that is composed of dominantly of calcite or dolomite mineral and forms from metamorphosing limestone or dolostone protolith a) anthracite coal b) Phyllite c) quartzite d) marble d) marble Name a metamorphic rock that is composed of partially decayed plants in swamps a) slate b) Phyllite c) anthracite coal d) marble c) anthracite coal Why does anthracite coal burn the highest of the coals? Anthracite coal burns the highest of the coal's because it has more carbon and less impurities. In order to produce anthracite coal they have to be anywhere in the ____ having more _____ pressure then it has _____ pressure. a) crust; lithostatic; differential b) mantle; lithostatic; differential c) crust; differential; lithostatic d) mantle; differential; lithostatic a) crust; lithostatic; differential True or False; if False restate to be true Minerals grow in the direction of more pressure False Minerals grow in the direction of less pressure What is a protolith? A protolith is the original rock of a metamorphic rock True or False; if False restate to be true Quartz is the most resist to weathering True What is the most common dolomitic marble? Calcite Name an example of regional metamorphism continental plate colliding with continental plate Name an example of contact metamorphism Oceanic plate colliding with continental plate or hotspot Name an example of dynamic metamorphism Along fault lines Name an example of hydro-thermal metamorphism Oceanic ridges Name an example of burial metamorphism The orogeny of mountains; rocks coming down off the mountain sides Cataclastic metamorphism (also called dynamic metamorphism) forms due to a) high pressure along faults b) high temperatures adjacent to igneous intrusions c) differential stress d) sandstone protolith a) high pressure along faults Contact metamorphism would be LEAST LIKELY to occur at which of the following plate settings? a) hot spot b) continent-continent collision zone c) divergent boundary d) subduction zone b) continent-continent collision zone Lithostatic pressure is a) due to the weight of overlying rock b) a uniform pressure c) a differential pressure d) due to the weight of the overlying rock and a uniform pressure d) due to the weight of the overlying rock and a uniform pressure Marble forms from metamorphism of _________. a) shale b) sandstone c) limestone d) basalt c) limestone Metamorphism of rocks adjacent to an igneous intrusion is _____. a) cataclastic metamorphism b) burial metamorphism c) hydrothermal metamorphism d) contact metamorphism d) contact metamorphism Rocks metamorphosed during the Grenville Orogeny about 1.1-1.3 billion years ago are exposed in the Adirondack Mountains of New York and ____. a) in the Texas panhandle b) in the Hill Country of Texas c) in the Rio Grande valley of Texas d) in East Texas b) in the Hill Country of Texas Which of the following is not a foliated metamorphic rock? a) schist b) gneiss c) quartzite d) phyllite c) quartzite Which of the following statements about metamorphism is NOT correct? a) Metamorphism occurs within Earth's crust. b) Metamorphism requires temperatures between about 200 and 700oC. c) Metamorphism requires pressures greater than atmospheric pressure. d) Metamorphism requires that there be a differential pressure in the crust. d) Metamorphism requires that there be a differential pressure in the crust. Which type of metamorphic rock has relatively smooth breakage surfaces? a) schist b) phyllite c) slate d) gneiss c) slate Which type of metamorphism commonly occurs along oceanic ridges? a) regional metamorphism b) burial metamorphism c) hydrothermal metamorphism d) cataclastic metamorphism c) hydrothermal metamorphism What does metamorphic grade refer too? Metamorphic grade refers to the general pressure and temperature conditions What is a mylonite? A mylonite is a highly strained rock produced as a result of cataclastic metamorphism How are foliated rocks classified? Foliated rocks are classified based on type of foliation How are non-foliated rocks classified? Non-foliated rocks are classified based on mineral composition Name a non-foliated rock that refers to rocks with minerals that typically forms from contact metamorhphism a) hornfels b) marble c) schist d) slate a) hornfels What is the metamorphic facies concept? Metamorphic facies concept – the mineral composition of a metamorphic rock reflects the rock type of the protolith (the original rock that was metamorphosed) AND metamorphic grade. This concept helps geologists determine things like what the P,T of metamorphism were and what the protolith was. That information can help answer questions like – how deeply were rocks buried (i.e. how tall was an ancient mountain belt), and what type(s) of environment(s) or plate boundaries existed prior to or during metamorphism.