Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
70 Cards in this Set
- Front
- Back
|
Detrital Sedimentary Rock |
rock formed by an accumulation of material derived from both chemical and mechanical processes |
|
|
Chemical Sedimentary Rock |
Sedimentary rocks formed from soluble material that is precipitated by organic or inorganic processes, which then cements particles together. |
|
|
fissility |
ability to split into thin layers along well-developed, closely spaced planes. shale exibits, mudstone does not |
|
|
(T/F) well sorted sedimentary rocks were formed when transportation takes a long period of time |
T |
|
|
Three properties of sedimentary rocks largely affected by tranportation |
Sorting |
|
|
(T/F) quartz is the predominant mineral in most sandstones |
T "quartz sandstone" |
|
|
What is sandstone called when it contains 25% or more feldspar? |
Arkose; usually contains quartz and bit of mica as well |
|
|
Define Conglomerate |
a detrital sedimentary rock with large, rounded particles |
|
|
Define Breccia |
a detrital sedimentary rock with large, angular particles; did not travel far |
|
|
What minerals are most abundant in detrital sedimentary rocks? |
clay minerals and quartz |
|
|
Define Shale |
sedimentary rock containing silt and clay size particles |
|
|
most common sedimentary rock |
shale (not noticed because it crumbles easily) |
|
|
Most abundant chemical sedimentary rock |
limestone |
|
|
difference between coquina and fossiliferious limestone |
Coquina loosely cemented
|
|
|
two types of inorganic limestone |
travertine: seen in caves oolitic limestone: small spherical grains caused by wave movement and layered with calcium carbonate from warm water |
|
|
define dolostone |
similar to limestone, calcium magneium carbonate mineral, non reactive to hydrochloric acid; unknown formation |
|
|
define Chert |
compact hard rocks made of micro-crystalline quartz; flint, jasper, agate. |
|
|
define Evaporites |
crystallization that occurs after salt-water evaporates; halite, gypsum |
|
|
what are the 4 stages of coal formation? |
1. Accumulation of plant remains 2. Formation of peat 3. Formation of lignite and bituminous coal 4. Formation of anthracite coal |
|
|
name 5 detrital sedimentary rocks |
1. conglomerate 2. breccia 3. sandstone 4. siltstone 5. mudstone/shale |
|
|
name 9 chemical/organic sedimentary rocks |
1. Crystalline Limestone 2. Travertine 3. Coquina 4. Fossiliferous Limestone 5. Chalk 7. Flint 8. Jasper 11. Rock Salt 12. Bituminous Coal |
|
|
Define Graded Bedding |
decrease in sediment size from bottom to top; associated with turbidity currents
|
|
|
Define cross-bedding |
beds that are inclined to the horizontal; form from sand dunes, river deltas, and some stream channel deposits |
|
|
Define strata |
sediment layer |
|
|
define facies |
vertical rock types that go through sediment layers, creating changes in a lateral layer |
|
|
What are the three broad categories of sedimentary environments? Give an example of each. |
Continental- glacial deposits |
|
|
What is the single most characteristic feature of sedimentary environments? |
strata |
|
|
Why might a single layer exhibit different types of sedimentary rock? What term applies to the different parts of such a layer? |
different environmental conditions along layer. facies. |
|
|
What is the difference between cross bedding and graded bedding? |
cross bedding occurs when the layers themselves are inclined due to the depository environment while graded bedding is when the grain size of the particles changes vertically on the layer. |
|
|
How might mud cracks and ripple marks be useful clues about the geologic past? |
If ripple marks were formed by air/water moving in one direction, their form will be asymmetrical, steeper on the downcurrent side. oscillation ripple marks result from back-and-forth movement of surface waves. Mud cracks indicate alternative wet/dry environments. |
|
|
What are the two broad groups of nonmetallic mineral resources? |
building materials-cut stone, aggregate, cement(limestone+shale)
|
|
|
what part of US energy consumption does each of coal, oil, and natural gas represent? |
coal: 20.4% natural gas: 25.5% |
|
|
What is an oil trap? |
A geologic environment that allows form economically significant amounts of oil and gas to accumulate underground |
|
|
Describe how chemical weathering and the formation of biochemical sediment remove carbon from the atmosphere and store it in the geosphere |
plants that decay still have carbon dioxide and are then deposited and buried underground |
|
|
Provide an example by which carbon moves from the geosphere to the atmosphere |
1. combines with water to form carbonic acid 2. attacks rocks that form crust 3. soluble product bicarbonate ion travels to ocean 5. die, eventually exposed on surface 6. chemical weathering releases CO2 |
|
|
Define metamorphic grade |
the degree to which the parent rock changes |
|
|
List four agents that drive metamorphism |
1. Heat 2. Confining Pressure 3. Differential Stress 4. Chemically active fluids |
|
|
Why is heat considered the most important agent of metamorphism? |
Heat provides the energy needed to drive the chemical reactions that result in the recrystallization of the minerals |
|
|
What's the difference between confining pressure and differential stress? |
confining pressure squeezes rocks equally on all sides; differential stress causes rocks to deform differently |
|
|
what role to chemically active fluids play in metamorphism? |
hot fluid chemicals can transport ions from one place to another, facilitating the process of recrystallization |
|
|
What's the importance of the parent rock in a metamorphic rock? |
the chemistry of the parent rock is relatively the same as the metamorphic rock, giving clues about it's origins |
|
|
Define: foliation |
foliation is the any planar arrangement of mineral grains or crystals within a rock |
|
|
Distinguish among: slaty cleavage, schistosity, and gneissic textures |
slaty cleavage: a property among slates that split into thin slabs schistosity: minerals discernable by naked eye from minute mica and chlorite flakes gneissic: light silica and dark minerals separate and form in bands |
|
|
Describe three ways in which the mineral grains in a rock develop a preferred orientation |
rotation of platy mineral grains re-crystallization that produces new minerals flattening spherically shaped grains |
|
|
what is meant by nonfoliated texture? Name one rock that exhibits this texture. |
do not exhibit foliation; marble |
|
|
name 7 metamorphic rocks+parent rock |
slate-shale,mudstone,siltstone phyllite-shale,mudstone,siltstone schist-shale,mudstone,siltstone gneiss-shale,granite,volcanic rock marble -limestone,dolostone quartzite -quartz,sandstone hornfels -any,usually shale |
|
|
Compare and contrast marble and quartzite |
marble is made from limestone or dolostone; soft quartzite is formed from quartz sandstone; hard they're both nonfoliated metamorphic rocks |
|
|
Name and describe 4 metamorphic environments |
Contact metamorphism: no pressure, no foliation, occurs in aureole Hydrothermal metamorphism: hot, ion-rich water chemically alters rocks(enhances recrystallization) via pores. Subduction zone metamorphism: oceanic crust subducts faster than it heats; differential stress regional metamorphism: two segments collide, causing great pressure. Most common m-rocks found |
|
|
Name three rocks that are produced by contact metamorphism |
mudstones/shales => hornfels limestone=>marble quartz sandstone=>quartzite |
|
|
Define aureole |
a section of rock that is heated by a magma chamber, creating contact metamorphic rocks |
|
|
What is the agent of hydrothermal metamorphism? |
ion-rich hot water |
|
|
List the common metamorphic rocks generated by regional metamorphism |
shale=>slate, phylite, schist, gneiss quartz sandstone=>quartzite limestone => marble |
|
|
Describe the different grades of metamorphism that might be encountered moving west to east from Ohio to the crystalline core of the Appalachians. |
* |
|
|
How do geologists use index minerals? |
Index minerals are minerals found in metamorphic rocks that have known melting temperatures, which are then used to associate the rocks into "grades", (low, intermediate, high)
|
|
|
Why are migmatites difficult to place into any one of the three basic rock groups? |
the felsic minerals melted and become igneous while the mafic minerals remain crystallized and metamorphic.
|
|
|
(T/F) metamorphism usually does not involve melting |
T |
|
|
Under what circumstances do most earthquakes occur? |
most earthquakes occur at preexisting faults where internal stresses have caused the crustal rocks to rupture or break |
|
|
how are faults, hypocenters, and epicenters related? |
faults are the faultline on which the movement occurs; hypocenters are the point along the fault at which slipping begins; epicenter is the point on the surface directly above the hypocenter. |
|
|
Who was the first person to explain the mechanism by which most earthquakes are generated? |
H.F. Reid of Johns Hopkins University |
|
|
what is meant by elastic rebound |
the rupture of the elastic pressure between two sides of a fault, which then regain a balance but at new orientations |
|
|
how long does an earthquake last that occurs on a 300km fault? |
~1.5 seconds |
|
|
(T/F) faults that do not experience fault creep may be considered safe. |
F, larger earthquake will occur, though less often |
|
|
What types of faults tend to produce the most destructive earthquakes? |
Megathrust faults; caused by the subduction of an ocean plate. |
|
|
List the major differences between P, S, and surface waves |
surface waves occur near earths surface; P and S waves are Body waves which are primary waves (push/pull) and secondary waves (shake at right angles to motion) respectively. |
|
|
Describe the movement of water through the hydrologic cycle. Once precipitation has fallen on land, what paths might the water take? |
evaporation, precipitation, runoff; infiltration (underground), runoff (surface), evaporation, or transpiration (soaked, then released by plants). |
|
|
Define evapotranspiration |
direct evaporation or indirect via plants (transpiration) |
|
|
List several factors that cause infiltration and runoff to vary from place to place and time to time |
Intensity and duration of rainfall Amount of water already in soil Nature of surface material Slope of the land Extent and type of vegetation |
|
|
What are three main parts of a river system? |
1. Sediment Production 2. Sediment Transport 3. Sediment Deposition |
|
|
What are the four drainage patterns? |
1. Dendritic-erosion resistance uniform, most common 2. Rectangular-bedrock crisscrossed by joints/faults. 3. Radial- form on isolated mountains/cones 4. Trellis-parallel pattern due to weaknesses in rock |
|
|
Contrast laminar and turbulent flow |
laminar flow is smooth, turbulent flow has higher energy and will more easily lift sediment. |
