Term
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Definition
| A rock is an aggregate of ONE OR MORE minerals. |
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Term
| What are some examples of rocks composed of more than one mineral? |
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Definition
| ex. feldspar, quartz, mica |
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Term
| What are some examples of rocks composed of only one mineral? |
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Definition
| ex. limestone, marble (both made of calcite) |
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Term
| What is the definition of mineral? |
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Definition
| A mineral is naturally occurring, inorganic, solid, and has a definite or very narrow range of chemical composition. Atoms must be arrange in a repeating pattern. |
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Term
| What are the mineral properties and why are they useful? |
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Definition
| The mineral properties are cleavage, hardness, lustre, crystal form, reaction to HCL, and streak. Colour is not a property because it tends to vary. Properties are used to identify minerals. |
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Term
| What is the definition of cleavage? |
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Definition
| minerals break along planar surfaces (smooth). this is due to an alignment of bonds within minerals -> surfaces of weakness. |
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Term
| What is the definition of a fracture? |
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Definition
| minerals do NOT break along planar surfaces, instead there are random jagged bits (irregular). or it breaks along smooth, curved surfaces -> conchoidal fractures. |
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Term
| Can a mineral break with both cleavage and fractures? |
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Definition
| yes. in some directions there can be cleavage, in some there could be fractures. |
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Term
| What is the definition of hardness? |
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Definition
| the ease with which a metal can be scratched |
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Term
| What is Mohs Hardness Scale? |
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Definition
| a scale of 10 minerals that have a varying range of hardness. |
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Term
List the hardness scale from 1 to 10.
(hint: Tall Girls Can Force Apart Oreos Quicker Than Clumsy Dudes) |
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Definition
talc
gypsum
calcite
fluorite
apatite (also your teeth)
orthoclase (feldspars)
quartz
diamond |
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Term
| Where on the hardness scale is your fingernail? |
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Definition
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Term
| Where on the hardness scale is a copper penny? |
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Definition
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Term
| Where on the hardness scale is a wire nail? |
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Definition
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Term
| Where on the hardness scale is a streak plate? |
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Definition
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Term
| Where on the hardness scale is a glass plate? |
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Definition
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Term
| What is the definition of lustre? |
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Definition
| how a mineral reflects light, either metallic or nonmetallic reflection of light. |
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Term
| What can be said about metallic lustre? |
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Definition
| a metallic colour also means a metallic reflection (silver, gold, bronze) |
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Term
| What can be said about nonmetallic lustre? |
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Definition
| nonmetallic is light or dark coloured, shiny or dull, but not metallic. |
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Term
| What defines submetallic? |
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Definition
| it breaks in sheets, is dark in colour (like a nonmetallic) but shines like a metal. |
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Term
| What defines crystal form? |
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Definition
| the shape a mineral will grow ONLY if the mineral grows into unrestricted, open space. most of the time they interlock with other minerals. |
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Term
| How can you tell apart a crystal or a cleavage fragment? |
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Definition
broken minerals (NOT CRYSTALS) show geometric shapes because they have cleavages. look to see if there are any fractures on the surface, if they are not the same as the mineral's fractures it is a crystal probably.
internal weaknesses |
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Term
| What is the definition of 'reaction to HCl'? |
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Definition
| some minerals will react with dilute HCl. |
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Term
| What is the definition of a streak test? |
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Definition
the colour of the powdered form of the mineral in question. the powder is often a different colour than the mineral in solid form.
ex: hematite is silver, streak is red |
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Term
| Why is colour not a useful way to identify a mineral? |
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Definition
| it is typically variable for most minerals |
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Term
| What are some other properties that can be used to identify a mineral? |
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Definition
| magnetism, optical properties |
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Term
| What are the 7 major mineral classes? |
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Definition
| silicates, native elements, oxides, sulfides, halides, carbonates. |
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Term
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Definition
| must contain Si and O in some combination. |
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Term
| How common are silicates and why? |
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Definition
| 95% of minerals in earth's crust are silicates. The earth's crust is made primarily of silicon and oxygen -> silicates. |
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Term
| What basic shape are silicates made of? |
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Definition
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Term
| What are some characteristics of silica tetrahedra? |
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Definition
| has an overall charge of -4 -> can't exist on its own, must bond with cations to balance the charge, or bond to oxygen to share electrons. |
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Term
| What are the two classes of silicates? |
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Definition
| nonferromagnesian and ferromagnesian silicates. (ferromagnesian silicates contain Fe and sometimes Mg) |
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Term
| What are native elements? |
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Definition
| minerals containing only a single element, like copper, gold, silver etc. |
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Term
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Definition
| they contain oxygen, ie. ice, hematite, corundum. |
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Term
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Definition
| they contain sulphur, ie. pyrite, galena, etc. |
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Term
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Definition
contain either chlorine, fluorine, bromine or iodine. (the halides)
ie. fluorite, halite etc. |
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Term
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Definition
| contain CO3, ie. calcite, malachite. |
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Term
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Definition
minerals that are similar CHEMICALLY and have the same crystalline structure are in the same group. they also have the same cleavage (based on atomic structure)
example: the feldspar group. all feldspars contain Si3O8, and each variety of feldspar contains varying amounts of other elements. |
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Term
| Give an example of a mineral group divided into species. |
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Definition
| ex. feldspar species - potassium (k-spar), plagiocase (plag) |
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Term
| What are the 7 common rock-forming mineral groups? |
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Definition
| olivine, pyroxene, amphibole, micah, feldspar, quartz, and calcite |
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Term
| Is the olivine group ferromagnesian or nonferromagnesian? |
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Definition
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Term
| What characterizes the olivine group? |
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Definition
they are commonly found as small grains within rocks
under the microscope, they are translucent green and have conchoidal fractures (looks like glass) |
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Term
| Is the pyroxene group ferromagnesian or nonferromagnesian? |
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Definition
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Term
| What characterizes the pyroxene group? what variety will we see in lab? |
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Definition
grains tend to be black or dark green, not translucent.
broken grains have 2 cleavages at 90 degrees
we'll be seeing AUGITE (the most common) |
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Term
| Is the amphibole group ferromagnesian or nonferromagnesian? |
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Definition
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Term
| What characterizes the amphibole group? what variety will we see in lab? |
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Definition
black and dark green
broken grains have 2 cleavages NOT at 90 degrees (56/124)
we'll be seeing HORNBLENDE |
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Term
| Is the micah group ferromagnesian or nonferromagnesian? |
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Definition
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Term
| What is the ferromagnesian type of micah? |
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Definition
| biotite - it is blackish coloured. |
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Term
| What is the nonferromagnesian type of micah? |
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Definition
| muscovite - it is clearish coloured. |
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Term
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Definition
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Term
| Is the feldspar group ferromagnesian or nonferromagnesian? |
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Definition
| nonferromagnesian silicates! |
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Term
| What are the 2 species of feldspar? |
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Definition
| potassium feldspars and plagioclase feldspars |
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Term
| What are the characteristics of feldspars? |
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Definition
colours vary way too much
break at 2 cleavages, 90 degrees |
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Term
| Is the quartz group ferromagnesian or nonferromagnesian? |
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Definition
| nonferromagnesian silicate! |
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Term
| What are some characteristics of quartz? |
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Definition
second most abundant in earth's crust
VERY HARD (7 on scale)
breaks with conchoidal fractures
colours are highly variable |
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Term
| Is the calcite group ferromagnesian or nonferromagnesian? |
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Definition
| NEITHER!!!!! it is carbonate!!!!! |
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Term
| What are some characteristics of calcite? |
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Definition
precipitated calcite forms sedimentary rock limestone
it has 3 cleavages not 90 degrees (rhombic shape)
reacts to dilute HCl |
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Term
| Who developed the continental drift hypothesis and when? |
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Definition
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Term
| What does the continental drift hypothesis state? |
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Definition
| about 200 million years ago, all continents were massed together as pangaea. since that time continents have drifted to their current locations |
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Term
| What was Wegener's evidence for continental drift? |
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Definition
| fit of the continents, matching up mountain ranges, fossils, glacial deposits, paleoclimate belts |
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Term
| Why was the theory rejected by the scientific community? |
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Definition
| Wegener had no answer to WHY the continents were moving. |
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Term
| Who developed the tectonic plate theory? |
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Definition
| many researchers over several years |
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Term
| What really started the tectonic plate theory? |
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Definition
| They had to map the seafloor during WWII, so they could hide submarines. since they mapped it they ended up having a way to look at the plates. |
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Term
| What did Harry Hess do and then discover? |
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Definition
| mapped portions of the seafloor and found massive ridges instead of flat |
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Term
| What did Hess do in 1962? |
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Definition
| proposes that MORs he mapped were locations where new ocean crust was being formed and old oceanic crust sunk back into earth at deep ocean trenches. |
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Term
| What else did Hess propose about plate tectonic theory? |
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Definition
| the mechanism for movement is mantle convection, where squishy hot rock rises and moves along surface, cools down, falls and then heats up again |
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Term
| What did Matthews and Vine do in 1963? |
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Definition
| presented paleomagnetic data from seafloor as evidence of spreading. |
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Term
| What causes the earth's magnetic field? |
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Definition
| as lava cools below 768 degrees, iron aligns itself with the existing polarity, and then the magma protrudes from the MORs and locks into direction of magnetic field |
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Term
| How does earth generate magnetism? |
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Definition
| liquid iron in outercore spins as earth does, generating magnetism. |
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Term
| What causes weakening and reversal in the magnetic field? |
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Definition
| there are big storms in the outer core that mess up the rotation, spinning can change directions. |
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Term
| How did Matthews and Vine get the data for their explanation of the magnetism of the earth? |
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Definition
| they dragged a magnetometer along the ocean floor and recorded the paleomagnetism locked in the crust. |
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Term
| How is the data from the magnetometer read? |
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Definition
positive anomalies indicate the same polarity as present.
negative anomalies indicate the opposite polarity as present. |
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Term
| What else does the data from the magnetometer prove? |
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Definition
| Since magnetic anomalies occur in stripes going out of the MORs, we can conclude that spreading occurs there |
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Term
| When was the last flip in the magnetic field? |
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Definition
| more than 50 000 years ago |
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Term
| What does the magnetic field do? |
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Definition
| protects us from solar flares etc |
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Term
| What did Tuzo Wilson discover in 1963? |
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Definition
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Term
| How did Tuzo Wilson discover the hot spots? |
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Definition
| he explained the presence of active volcanism far away from plate margins, because of deep mantle hotspots that the area travels over. magma flows up and produces a chain of volcanoes that increase in age away from the active hotspot. |
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Term
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Definition
| nope! the plate moves and makes new islands. |
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Term
| What did Tuzo Wilson predict in 1965? |
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Definition
| the presence of transform faults connecting offset segments of MORs |
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Term
| Why do transform faults exist? |
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Definition
| because spreading around a sphere means you can't subduct it all at the same rate, the MOR cannot connect in one big line. |
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Term
| How were transform faults confirmed? |
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Definition
| Vine and Matthews used paleomagnetic data off the west coast of North America. |
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Term
| What happens at mid ocean ridges? |
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Definition
| Diverging (new materials) |
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Term
| What happens at deep ocean trenches? |
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Definition
| Converging (old materials recycled) |
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Term
| How else do we know that new material is near the MORs? |
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Definition
| Deep sea drilling to remove rock from the floor. |
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Term
| Where are sediments thinnest on the ocean floor? |
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Definition
| thinnest near the ridge crest, thickest further away. |
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Term
| How do we measure the distance of spreading and in what units? |
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Definition
| Satellites; cm/year (very slow) |
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