Geology Final Exam
Terms
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- Isoclinal Fold
- A very tight series of fold structures standing up side by side in a vertical orientation
- Strike Slip
- When the movement is lateral (side to side)
- Monocline fold
- A structure that bends down on one side of the axis line
- Time Travel Curve
- Represents the distance covered by the seismic energy
- Mercalli Scale
- Oldest scale used to measure earthquakes. Calculated based on relative intensity (I-XII)
- Evidence of continental drift
- fitting of continents, fossils, structures, climates
- Continental-continental
- Because the continents are not dense enough to subduct, when the two plates collide mountain ranges are formed, such as with the Himalayas
- Seismometer
- Detects the seismic energy
- Transform
- Slide horizontally, San Andreas fault
- Epicenter
- Point on the surface directly above the focus of the earth quake
- Reverse fault
- A dip slip fault where the hanging wall black moves up relative the footwall block
- L Waves
- (long waves) long the outer perimeter of the crust, slowest of all (surface wave)
- Standard Geologic Time Scale
- A scale created by geologists who have divided the whole of geologic history into units of varying magnitude
- Absolute Dating
- Radiometric decay rates happen at a fixed rate that does not change due to physical conditions
- Dip Slip
- When the movement is vertical displacement and moves up and down
- Shearing stress
- Deforms rock material immediately along the fault line itself.
- The closer the focus is to the surface the ____ the power of the quake
- Higher
- Cenozoic
- Recent Life
- Plunging fold
- Reference to the orientation of the central axis line, when it plunges into the interior of the earth
- Index fossils
- Fossils that are widespread geographically and are limited to a short span of geologic time so their presence provides an important method of matching rocks of the same age.
- Tensional Stress
- Stretching
- Left lateral strike slip fault
- When the movement is to the left
- Core
- 2200 miles thick
- Nonconformity
- The break separate older metamorphic or intrusive igneous rocks from younger sedimentary strata
- P Waves
- (Primary), Compressional waves, fastest (body wave)
- Syncline fold
- Opposite of a anticline. A trough like structure (think of a u-shaped)
- Triangulation
- Used to pinpoint the epicenter of the earthquake,
- Mantle
- 1800 miles thick
- Basins
- Opposite of domes, a collapse that is associated with sink holes, youngest material in center
- Oldest Earth rock
- 3.8 B
- Moho
- The shortened name for the boundary that separates the crust from the underlying mantle
- Continental Drift
- theory that states that there was a supercontinent that split into the continents of today, founded by Wegener
- Thermoluminescence
- The phenomenon where certain items such as pottery that have been heated in the past will give off a light when exposed to ultraviolet light.
- Benioff
- the area in the subduction zone where movement creates earthquakes.
- Right lateral strike slip fault
- When the movement is to the right
- Oceanic-continental
- Where the denser ocean plate subducts under the more buoyant continental plate. The oceanic plate starts to partially melt and sometimes creates volcanic activity on the edge of the continental plate. Mt. St. Helens
- Dip
- Refers the direction and angle of inclination
- Oceanic-Oceanic
- Happens the same way as oceanic-continental and this is how volcanic islands are formed. IE: Hawaii
- Paleozoic
- Ancient Life
- Lithosphere
- the solid part of the earth consisting of the crust and outer mantle
- S Waves
- (secondary), Causes rock to vibrate perpendicular the mode of travel, slow (body wave)
- Oldest Moon rock
- 4.6 B
- Recumbent
- Extremely rare, material holds together to bend and tilt at an angle and will lay all the way over on its side so its at a horizontal orientation
- Convergent plate boundaries
- Where two plates move together resulting in oceanic lithosphere descending beneath an overriding plate or possible the creation of a mountain system.
- Principle of Original Horizontality
- Created by Nicolaus Steno; Layers of sediment are generally deposited in a horizontal position. Thus, if we observe rock layers that are flat, it means they have not been disturbed. If they are folded or inclined at a steep angle they must have moved into that position by disturbances
- Disconformity
- More common than angular unconformity but harder to detect because the strata on either side of the disconformity are parallel
- Andrija Mohorovicic
- A scientist who first presented the idea behind the earth being in layers by studying seismic records he found that the velocity of the waves increases abruptly below about 50 kilometers of depth.
- Mesozoic
- Middle Life
- Compressive stress
- Compaction
- Strain
- The physical response to stress
- Tsunami
- Japanese word for Seismic Sea Waves, Must have actual displacement of the sea floor, a series of waves
- The nature of the movement of earthquakes is both ___and ___
- horizontal & vertical
- Seismograph
- Creates "paper print outs" of the energy
- Principle of Super Position
- When looking at a rock formation you can see their original horizontality and determine their relative dating age.
- Seismic Waves
- Move outward in all directions from the focus of the quake
- Angular Unconformity
- Consist of tiled or folded sedimentary rocks that are overlain by younger, more flat-laying strata. Indicates that during the pause is deposition, a period of deformation and erosion occurred.
- Fault
- When a rock breaks and moves
- Elastic strain
- The material will bend and then move back
- Beno Gutenberg
- A scientist who that P waves diminish and eventually die out at a certain spot on the globe after an earthquake. Then the P waves would re-appear but later than expected. It was concluded from this then that the earth had a "core" that bends the waves.
- Good Friday Quake
- 1964 in southern Alaska. 9.3 Richter.
- Asthenosphere
- the soft layer of the mantle that the lithosphere floats on
- Focus
- Actual point where movement takes place
- Normal fault
- A dip slip fault where the hanging wall block drops down relative to the footwall block
- Paleomagnetism
- Study of the earth's magnetic field through the use of magnetic minerals over time.
- Joint
- Where a rock breaks from stress
- Anticline fold
- When the material bends upward and forms a ridge like structure (think of a dome)
- Hotspot
- When a rising plum becomes a surface manifestation, Hawaii
- Relative Dating
- Sequence of events or formation
- Strike
- Refers to a line of compass direction formed by the intersection between and incline plane and a horizontal plane
- Crust
- 5-40 miles thick
- Domes
- Round symmetrical hills that are pushed up by a plume of salt, oldest material in center
- Overturned fold
- If it is laid over at an angle, (leaning)
- Open fold
- If it is just slightly bent
- Richter Scale
- Created by Dr. Richter. Calculated by magnitude (0-9.3)
- Shadow zone
- area where the p-waves disappear
- Fracture strain
- When the material will bend and snap
- Principle of Cross-cutting Relationships
- When a fault cuts through other rocks, or when magma does, we can assume that fault or dike is younger than the original rock.
- Faunal succession
- That certain fossils will never be found together. You can identify a strata of rock by its fossils
- Oblique Slip
- When the movement is at an angle
- Plastic Strain
- The material will bend and stay that way it is
- Thrust fault
- Reverse faults with a very low dip angle to them