Term
| What factors influence a violent eruption? |
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Definition
| Composition- more SiO2 means more viscosity, Temperature- more viscosity at lower temperatures, and gas(volatile) content- the more gas the more explosive. |
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Term
| What has more SiO2 mafic or felsic rock? |
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Definition
| Felsic rocks 70-75% SiO2 vs Mafic- about 50% or less. |
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Term
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Definition
| a Material's resistance to flow. Also the more viscous a magma is the more violent it's eruption will be. |
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Term
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Definition
| Gases held in the magma. As the near the surface the pressure lessens and the gases inside expand causing violence. |
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Term
| Explosive vs Effusive eruptions |
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Definition
| Explosive- are violent with high viscosity and a lot of trapped gas. Effusive- are passive with low viscosity and gas that escapes easily. |
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Term
| Main types of volcanic structures |
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Definition
| Shield, Cinder Cones, and Composite. |
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Term
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Definition
| From passive eruptions/lava flows. Huge structures with massive width to height ratios. They occur on other planets too. |
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Term
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Definition
| Can be explosive and passive, are short lived round piles of tephra from jets of lava that cool in mid-air and are then deposited around the flank of the volcano. have 45 degree angle of repose and erode very quickly. |
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Term
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Definition
| Usually explosive and can also be called a stratovolcano because they can blow rocks up into the stratosphere. They have steep slopes and are cone shaped. Often associated with layers of tehpra and lava flows. Tend to be associated with subduction and are very unstable. |
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Term
| How did Mt. St. Helens erupt and when? |
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Definition
| it gained a geotumor in 1980 and exploded violently. |
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Term
| What are the two types of lava? |
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Definition
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Term
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Definition
| smooth to the foot, has a smooth ropey appearance |
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Term
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Definition
| rough to the foot. This lava cascades forward and is rough, jumbled and jungly. |
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Term
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Definition
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Term
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Definition
| A jet of lava sprayed into the air by the rapid formation and expansion of gas bubbles in the molten rock is called a lava fountain. Lava fountains erupt from isolated vents, along fissures , within active lava lakes , and from a lava tube when water gains access to the tube in a confined space. |
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Term
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Definition
| (driblet cone) Small (usually 5–20 m high), volcanic cone built from tephra blown out as clots of relatively fluid basaltic lava. |
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Term
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Definition
| currents of "flaming" lava from a crack. |
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Term
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Definition
| Lava can move in tubes. A "Skylight" is an opening into an underground tube system of lava. |
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Term
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Definition
| name for pliny the younger, conists of hot ash, rock fragments and gases being erupted from an explosive vent in a plum up to 100,000 ft or 5 miles high. The fragments can call at up to 100mph after the column collapses. |
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Term
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Definition
| ash, gas and rock fragments. move at about 200 to 560 mph or 100 to 250m/second. Incredible destructive and leave deposits behind called "tuff" |
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Term
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Definition
| pyroclastic flow deposits |
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Term
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Definition
| also called bombs. Rocks are generally small but can be the size of a car or house. they are hot on the inside so they explode like a grenade on impact. |
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Term
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Definition
| Have killed the most people over the last few 100 years. They are volcanic derived mudflows. rocks mixes with melted glaciers/snow caps or nearby bodies of water. They can be produced by a volcanic eruption or in between eruptions. they travel upwards of 60km/hr but are very viscous and impossible to swim out of. |
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Term
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Definition
| Composed of ash, pumice, and rock fragments. fallout tends to pile up on buildings and cars causing damage and collapse. If breathed in it will coat your lungs with glass and cause asphyxiation. |
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Term
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Definition
| also called caldera forming eruptions. They are extremely large scale and erupt upwards of 1000 cubic kilometers. their fall deposits cover continents and the ash covers the globe causing global climate change. could end human existence. |
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Term
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Definition
| when an explosion causes collapse of the volcano into the magma chamber, can be up to 60km across is a cyclical process. |
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Term
| Volcanoes linked to climate change |
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Definition
| 1815 volcano tamboro exploded and in 1816 it snowed in july in NE. |
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Term
| Examples of super volcanoes |
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Definition
| Crater lake, Oregon, Yellowstone, Krakatau, and Tambora(caused the snow). |
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Term
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Definition
| Vibrations of the ground created by the sudden release of energy accumulating in deformed rocks. |
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Term
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Definition
| Also called the hypocenter this is the point of origin of an earthquake. aka where the rock actually begins to rupture or move. |
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Term
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Definition
| The point on the earth's surface directly above the focus. |
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Term
| Name the different type of Seismic Waves of an Earthquake. |
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Definition
| Body waves (P and S) and Surface waves (L and R) |
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Term
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Definition
| compression waves. They are the fastest at 4 mi/sec and travel through anything |
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Term
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Definition
| Have vertical or horizontal motion. Travel at 2 mi/sec and do not move through liquid. |
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Term
| Calculating distance from an earthquake. |
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Definition
| Use the distance between the P and S waves. To locate the epicenter use 3 distance circles... |
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Term
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Definition
| Are surface waves. at 1.5mi/sec they are the slowest waves. L travel side to side and R travel up and down. together they have complex motion |
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Term
| What determines a earthquakes strength? |
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Definition
| Depth of the fault-deeper depth means it's less powerful. Strength of rock- stronger rocks are more powerful when the rupture. And the total amount of slip, the more the more powerful. |
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Term
| Where do earthquakes occur? |
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Definition
| Mostly along plate boundaries, though the can also occur along hot spots, and sometimes occur as intra-plate quakes. |
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Term
| How do intra-plate quakes happen? |
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Definition
| Ancient plate is reacctivated, there is a crustal weakness, isotacy or rebound after a glacier leaves and nearby magma. |
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Term
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Definition
| rebound after weight like a glacier leaves. |
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Term
| How do we measure earthquakes? |
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Definition
| With a sesmograph that puts out a sesmogram. |
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Term
| The seismic shadow zone phenomenon |
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Definition
| S waves don't go through liquid and P react wierdly through liquid. Both phenomenon create shadow zones so that you can't figure out where and earthquake is if you are within 103 degrees on either side of the earthquake. |
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Term
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Definition
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Term
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Definition
| Qualitative (measure of the damage) ranges from I being the least damage to XII being the most damage and is based on relative levels of destruction. |
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Term
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Definition
| Quantitative (Measured by energy). Is based on a scale of 1 to 10 and goes up logarithmically. Is based on the amplitude of the seismogram. Largest earthquake ever recorded was a 9.5. 2004 Tsunami was caused by a 9.3. |
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Term
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Definition
| an earthquake hazard. can damage or collapse other buildings or structures. |
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Term
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Definition
| normal or reverse faults that cause structures to split. is another earthquake hazard. |
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Term
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Definition
| rock/cliff face that is visible after the ground drops down due to a fault. |
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Term
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Definition
| another earthquake hazard. |
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Term
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Definition
| Energy from an earthquake causes sediment to vibrate and behave like a liquid. caused water and other liquids to come to the surface. |
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Term
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Definition
| another earthquake hazard that can be caused when an earthquake breads a fuel line, gas pipe or the water pipes need to but out a fire. |
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Term
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Definition
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Term
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Definition
| a crazy wave triggered by the ground shifting from an earthquake or by landslides/earthquakes nearby the water. Is a global phenomena. Can travel upwards to speeds of 500 mi/hr and can be 45 to 50 ft tall when it breaks on the shore. On the ocean you just get swells... |
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Term
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Definition
| can be achieve by seismic zoning rules, better building codes, stronger structures (that can accommodate seismic stresses), and taller columns which can sway better without breaking. |
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Term
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Definition
| was a 9.3. killed over 200,000 people, displaced 1.69 million people. |
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Term
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Definition
| Education and better warning systems. |
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Term
| How do rocks become deformed? |
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Definition
| Stress(usually tectonic) leads to strain. |
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Term
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Definition
| Tension (Pulling apart), Compression (Pushing together), Shear (twisting or torsion). |
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Term
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Definition
| Ductile (plastic smooth continuous), Brittle (sudden break), Elastic (deforms then returns back to it's orginal shape-ucommon!) |
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Term
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Definition
| smooth and continuous leads to folding, shearing and stretching. |
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Term
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Definition
| Catastrophic and sudden. earthquakes are the result of brittle deformation. leads to faults. |
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Term
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Definition
| Reverse causes compression(head wall goes up), normal causes extension (head wall goes down), and strike-slip causes shearing. |
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Term
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Definition
| result when ductile rock undergoes compression |
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Term
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Definition
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Term
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Definition
| Concave or u-shaped fold. |
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Term
| Horizontal vs plunging fold. |
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Definition
| Plunging fold plunges away from the horizontal and results in arcs on the surface. Horizontal folds have straight lines at the surface. |
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Term
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Definition
| Normal and reverse faults. Motion is vertical. |
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Term
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Definition
| Low angle reverse faults. Layers are thrust up and over other rocks. |
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Term
| Right lateral vs left lateral. |
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Definition
| Stand on one side of the fault and look across to the other side has the rock been offset to the right or the left. |
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Term
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Definition
| Broad circular or oval upward bulges of rock layers. Rock layers tilt / or outward from the center of the dome. forms uplift in the center and has oldest rocks in the center. |
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Term
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Definition
| circular or oval downward sag of rock layers. Rocks tilt \ away from center. form from subsistence or sinking of the center and have youngest rocks at the center. |
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Term
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Definition
| The direction of the intersection of a rock layer with the horizontal surface. |
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Term
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Definition
| the angle and direction at which the beds are incline from the horizontal. (always perpendicular to strike. |
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Term
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Definition
| The vastness of the geological record. (earth is 4.6 billion years old) |
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Term
| Relative vs Absolute dating |
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Definition
| comparison vs specific number dating. |
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Term
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Definition
| stratigraphic succession is chronological record of the geologic history of a region. |
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Term
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Definition
| sediments are deposited as essential horizontal beds |
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Term
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Definition
| In an undisturbed sequence the oldest rock is at the bottom and the younger stuff is on top. |
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Term
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Definition
| rocks containing the inclusion is younger than the enclosed piece of rock. |
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Term
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Definition
| what ever is cutting is younger than what ever is cut or offset is older. |
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Term
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Definition
| thermal metamorphism occurs when country rock is invaded by a plutonic igneous intrusion. The backed rock is thus older. |
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Term
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Definition
| indicate missing time in geological record from erosion or nondepositon. |
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Term
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Definition
| between relatively parallel strata. |
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Term
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Definition
| between sedimentary rock and non-sed rock. |
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Term
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Definition
| between non parallel strata. |
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Term
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Definition
| prevalent fossils may be used as index fossils or markers in stratigraphy. |
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Term
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Definition
| calculated ratio of parent isotopes to daughter isotopes. Needs a closed system. Is great for igneous rocks, ok for metamorphic rocks (rest at metamorphism) and is awful for sed rocks. |
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