Final Exam Flashcards
How do sedimentary rocks begin?
They begin by being weathered away and transported into a sedimentary basin
How are sedimentary rocks lithified?
Compaction and cementation
What is the Angle of Repose
The maximum angle at which a slope that has loose material will sit without sliding.
If you have sandstones that are compacted and lithfied what kind of rock can you expect to find?
sandstone
If clay particles are compacted and lithified what can you expect to find?
shale
A measurement of the space between grains in a rock is called?
porosity
The measure of interconnectedness between pores is called
permeability
Sedimentary rocks include which two lists of the following rock groups?
- limestone, gypsm, salt deposits
- Shale, sandstone, conglomerates
A meandering stream has which of the following characteristics
A single channel with a winding course that has a low velocity
An area adjacent to a stream that is built up when a stream floods. After flood waters have deposited mud and silt, this landform is made
natural levees
What is a braided stream
a stream with many winding and separated channels
False River is a
Oxbow lake or a cutoff meander
The transportation process of sand grains in water by moving them along in a series of short intermittent jumps is
Salitation
What is the most fertile place to grow crops?
A floodplane
The high landform that rain runoff on either side
Divide
At a bend in a meander ______ happens on the outside bend and ____ occurs on the inner bend.
erosion, deposition
What is a part of a streams bed load
sand grains or pebbles
Which of the following river deposits are clay and mud?
Overbank deposits and floodplanes
Which of the following terms describes a curved, coarse-grained sand deposit that forms on the inside curve of a stream channel?
point bar
What does an oxbow lake look like?
A cut off horseshoes
Cone-shaped deposits of sediment built up at the base of a mountain stream in dry climates are called
allevial fan
What kind of drainage system would you see at the base of a mountain to coastal plain
dendritic drainage system
The New Orleans French Quarter did not flood after Katrina because the early settlers built on what river feature.
Natural levee
A cone- or fan-shaped accumulation of sediment deposited where a river or stream enters a large standing body of water, such as where the Mississippi River enters the Gulf of Mexico, is a(n):
Delta
The Base Level of a stream is
The elevation at the end of a stream where it enters a large standing body of water.
Which material is transported as suspended foam?
clay
Groundwater
Water that seeps down from the land surface, then fills the empty spaces and cracks in sediments and rock at depth
Auquifer
where groundwater is stored.`
Ground water table
The upper surface of the saturated zone.
Sinkhole or cave
A Karst terrain erosional feature formed by groundwater dissolving limestone bedrock
“The recharge area for the Southern Hills Aquifer”
An area in southern Mississippi where precipitation infiltrates into the ground and contributes to the local groundwater supply
List 3 types of sedimentary structures that can be preserved in the rock record
- bedding - stratification beding
- rippling (cross bedding) - looks like waves of sand or slit
- biologial strcutures
Sediments are kept in the rock record via burial within one of these structures and then lithification is what happens to chemically change those sediments into sedimentary rocks.
What have you learned about Baton Rouge’s drinking water?
Baton Rouge’s drinking water comes from groundwater and it is no lower than 3,000 feet below us. Unlike in New Orleans, our drinking water does not come from the river.
Additionally, in class we discussed how the plant uses ground water and this is causing there to be less potable drinking water for the general population.
Velocity of a Stream
Area x velocity = discharge
why you would expect to find coarse grained sediments at the bottom of a channel or in the trough of a ripple?
denser/heavier and can’t be suspended in the water column.
Three types of shorlines
1)Straight and sandy beach (North Carolina example)
2) Rocky (Mt. Dessert, Maine)
3) Reef and Beach (Southern Florida)
The North American craton is composed of
Highly faulted, folded, and metamorphosed rock due to repeated orogens through billions of years
The oldest rocks on Earth are found in
Craton
Oregoeny
a mountain-building event
Current mountain building event
The Himalayan Mountains and the intersection of Indian and Eurasion Continental Plates
Brittle
A rock body is subjected to a force, and it deforms by breaking or faulting
Reverse fault
compressional force
According to the __________, earthquakes occur when ___________ accumulates until it exceeds the strength of the rock.
elastic rebound theory, stress
Earthquakes that occur along continental tectonic rift valleys are associated with ______ faults.
normal faults
Seismic P waves and S waves
earth’s interior
Focus center
where the rupture occurs that causes an earthquake
Epicenter
location on the earth’s surface that represents where an earthquake
principle of superposition
states each sedimentary layer of an undisturbed sequence is younger than the one beneath it and older than the one above it is
Principle of faunal succession
sedimentary rock layers in an outcrop contain distinct fossils in a definite sequence
Principle of horizontally
sediments are deposited as essentially horizontal beds
Principle of cross-cutting relationships
cross-cutting members (think intrusions, veins, faults, or other) are younger than the layers they cut across
Relative ages of rocks may be determined using
Both the principle of original horizontality and the principle of cross-cutting relationships
Syncline
Is ‘U-shaped’ in cross-section and is the result of compressional stress
Reverse Fault
compressional stress
Outcrop
bedrock that underlies the earth’s surface is exposed.
Geologic maps
represent the earth’s surface
During metamorphism, a rock undergoes mineralogical and textural changes
While in a solid state with heat and pressure
Contact metamorphism
type of metamorphism created by the intrusion of an igneous dike into shallow pre-existing rock
Gneiss
A kind of high grade metamorphic rock
Foliation
the crystal like structure in metamorphic rock caused by directional stress
non-folaited rocks
quartz and marble
Ways to reduce risk of earthquakes
First, proper land use policies that avoid zones with common earthquakes. In the lecture we discussed avoiding the mistakes that were made in construction along the San Andreas fault line.
Next, proper emergency planning such as the tsunami wall that was built in Japan.
Finally, earthquake building codes and engineering requirements.
3 characteristics of mass movement
(1) nature of the slope or the angle
(2)the amount of water present
(3)the steepness and stability of the slope
Unconformity
a missing layer of rock
Physical Weathering
When a rock is broken down into particles (sand, gravel, boulders), clay minerals, and dissolved ions
Chemical Weathering
When a rock is broken down through chemical processes rather than mechanistic processes
3 process that cause erosion
Erosion is the process by which of sediments are removed through natural causes such as wind, bodies of water (such as rivers), or the melting of glaciers.
Thus, three natural process that frequently cause erosion are:
(1)wind
(2)river movement and progression
(3)melting of glaciers
Sequences to describe geologic time
(1) Eons
(2) Eras
(3) Periods
Mass Movement
The downward progression of materials by the force of gravity
How can you describe earth science or geology?
A process of observing present conditions and the rock record, creating and testing hypotheses to explain ways that different rocks types are formed, and relating these to the development of the Earth
Where can you find a convergent tectonic plate boundary on an unknown continent
Deep sea trench offshore or near a line of volcanos
Earth systems
(1) Climate
(2) Geodynamo
(3) Plate Tectonic
Convergent Boundary
Oceanic crust subduct to make a chain of volcanos
Mid Ocean ridges are:
(1) spreading centers
(2) Places where no crust is created
Actualism
Applications of a modern process to an ancient system.
Catastrophism
catastrophic events such as (1) volcanic activity (2) earthquake activity (3) impact activity
Pangea
The name of an ancient supercontinent that made up of all present day continents
Geology is a
diachrnous science
Continental crust
less dense and floats on oceanic crust
Earth layers in order
(1)crust
(2) mantle
(3) outer Core
(4) inner Core
Mineral
naturally occurring crystalline structure, generally inorganic, specific chemical composition
Atlantic Mid-Ocean Ridge
divergent boundary
Rock
natrually occuring solid aggrigate of minerals or non-mineral solids
Mohs Scale of Hardness Level 1 examples
Talc and baby powder
Principle of Uniformitarianism
The present is the key to past
Hot spots or mantle plumes location
On the ocean floor in spots like Hawaii
A passive continental margin is an area of
(1) Beaches and shallow seas
(2) Swamps and Marshes
Active continental margin
(1) Volcanic activity
(2) Mountain building
(3) tectonic plate boundaries
Mantle Convection?
drives plate tectonics
Convergent margins
Crust is sub ducted and pushed back into the mantel
Moh’s Scale of Hardness: Dimond
(1) Hardenss of a 10
(2) Glassy fracture
Isochrons and mid ocean divergent boundaries are
closer together to indicate spreading
James Hutton
Father of modern geology
An igneous rock contains mostly quartz, in the form of silica, and feldspar is
felsic
first minerals to crystallize out of a melt are
Olivine and calcium
NOT magmatic intrusions
Lahars, cinder cones, and calderas
Igneous rocks form from
Molten liquid deep in the earth
Large intrusion of felsic magma deep in the Earth forms a
Granite Batholith
igneous intrusion
sill or concordant
Intrusive ingenious rocks
cool slowly
Stratovolcanoes
Volcanoes made of alternating layers of lava and pyroclastic material
shield volcanos
broad and dome shaped
Maurice ‘Doc’ Ewing
Young Oceanic crust
Vine & Matthews
seafloor spreading
J. Tuzo Wilson
Plane geometry
Alfred Wegener
Continetal drift
Harry Hess
seafloor bathymetry
Ring of Fire
Describes all of the volcanoes and earthquakes that occur on the continents edges’ that surround the Pacific Ocean
Hugo Benioff
Seismeticity
Felsic
GRanite
Mafic
Gabbro
Arete
knife-like ridges between
glacial valleys
forms by erosion on opposite sides
Cirque
amphitheater-shaped bowls on
mountain peaks
forms at the head of a glacial valley
Continental glacier
a large, continuous sheet of ice that covers a large area of land
Fjord
submerged U-shaped valleys
Glacier
Formed by glacier cycle
(1) snow accumulates (snow)
(2) crystalizes into ice (granular ice)
(3) With pressure ice starts to flow like vicious liquid (firn)
–> Glacial ice with only 20% bubbles
Forms as the result of the glacial budget
Glacial Till
unstratified,
poorly sorted, allpoorly sorted, all
sizes)
Sierra Neveda
Moraine
cumulation of rocky, sandy, clayey
material carried and deposited by the ice material carried and deposited by the ice
–> Many Types of morraines – named for position
U-shaped valley
forms by valley glacier’s erosion
Yosemite valley is an example
Valley glacier
alpine glaciers like junea alaska
Eolian
pertain to wind activity in the study of geology and weather and specifically to the wind’s ability to shape the surface of the Earth
How do sand grains travel in deserts
Sand grains travel in deserts via ripples (or dunes) just like they travel in water
wind moves it like a conveyer belt
3 types of dunes
(1)barchan - crescent shape. Product of limited sand supply and unidirectional wind
(2)linear - moderate sand supply, rough movement but wind is directional
(3)transverse dune - form in air desserts where there is abundant sand.
Loess
fallen atmospheric dust creates a
deposit
Chenier
Continental shelves
● low sloping offshore area
● economically important (drilling for oil and natural gas)
Continental slope and rise
● canyons and submarine fans occur
● turbidity flows of sediment
Factors that influence shoreline erosion and deposition
● uplift / subsidence
● nature of rocks or sediments
● changes in sea level
● storm wave impact
● heights of tides
Storm surge
Important factor when hurricanes or other large storms push water onto land. It
can be described as the added height of water that comes ashore with a storm. Can do significant
damage onshore.
Waves
crest and trough, wavelength- distance between wave crests, wave height- the vertical distance between the crest and trough, and period – the time it takes for 2 successive wave crests to pass a certain point
Glacial Sediment
poorly sorted
mix of boulders to clay
