Exam 3 Flashcards
How do we date geologically (relative versus absolute)?
Relative and absolute dating techniques
assumes the same physical processes that are occurring today have operated throughout geologic time
uniformitarianism
What is superposition?
younger rocks are superimposed on top of older rocks
What are cross-cutting relationships?
Geologic features such as faults that cut across rock must be younger than the rock cut through
What is the structure of Earth?
Core,Mantle, Moho, Crust
inorganic, natural compound with a specific chemical formula and possessing a crystalline structure
Mineral
What are the types of minerals?
Silicates
Oxides
Sulfides & Sulfates
Carbonates
What is the most prevalent in our crust?
Oxygen
an idealized cycle of processes undergone by rocks in the earth’s crust, involving igneous intrusion, uplift, erosion, transportation, deposition as sedimentary rock, metamorphism, remelting, and further igneous intrusion.
rock cycle
What’s the difference between igneous, metamorphic, and sedimentary rocks? What are some examples?
F
The way they are formed.
Igneous is formed by from the cooling of liquid hot magma.
EX. Granite
Metamorphic is formed by a physical and chemical changes brought on by increased pressure and heat
EX. Marble
Sedimentary is formed by loose clasts (grains or fragments) are cemented together
EX. Sandstone
is the theory that Earth’s outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core.
Plate tectonics
What are the different plate boundaries and how do they move in relation to each other?
Divergent, Convergent, and transform plate boundaries.
Divergent- two plates moving away
Convergent- two plates move towards
Transform- two plates sliding past each other
What is stress?
force over a given area
What is strain and what happens when Earth is strained (i.e., folds and faults)?
how rocks respond to stress
Folding (bending)
Faulting (breaking)
What are the three types of faults?
Normal
Reverse
Strike-Slip (Left and Right Lateral)
Sudden movements along plate boundaries, releasing enormous amounts of energy.
Earthquake
What type of activity occurs at a volcano?
Effusive eruptions and Explosive eruptions
How does viscosity and gas build up change the type of volcano?
It changes the type of volcanic landforms
Viscosity effects if the volcano will actually have flowing lava or not
What is the difference between a composite and shield volcano?
Shield Volcanoes are generally not very high and the magma they produce is quite runny.
A Composite Volcano is the cone shaped volcano. When they erupt, they produce lots of ash and quite little magma.
any process that wears down or rearranges landforms
denudation
What are examples of Physical and Chemical weathering
Example of Physical: Frost wedging, root wedging, Salt wedging, Thermal Expansion, animal attack and wind
example of chemical: Dissolution, Hydrolysis, Oxidation, hydration.
What is karst topography and what are some of the features?
Limestone areas chemically weathered by moisture
Caves, Caverns and sinkholes
How does karst topography form?
Limestone dominated by calcium carbonate (>80%)
Existing jointing (water can move through)
Aerated portions underground
Groundwater and vegetation
What is mass movement? What are the classes? How are they different (speed and water content)
Any unit movement of a body of material under gravity
Fall (rockfall)
Slide (landslide, slump)
Flow (earthflow/mudflow)
Creep (soil creep)
What are the fluvial processes (function)?
Drainage
Erosion
Transportation
Deposition
an area of land where runoff collects and moves through the same area
Drainage Basin
What are the different types of materials carried by streamflow?
sediments and rocks
What are the different types of streams and what are some of the characteristic features?
Braided – several interconnecting channels
Meandering – a single winding channel
What are floods and how do we rate them?
when high water levels overflows the natural banks and levees of a river
Floods are rated statistically by their probability of reoccurrence
How does wind affect our Earth?
Deflationand Abrasion
What are the three climate controls?
Subtropical highs (15-35oN&S) Rain shadows of mountains Continentality
What are the desert fluvial landforms?
Flash flood Wash Playa Exotic streams Alluvial Fan Bajada
What is desertification? What are the problems associated with this?
Expansion of deserts
Problems include dust storms, loss of water resources, spread of diseases
What are the deserts of North America?
Chihuahuan
Sonoran
Great Basin
Mojave
an accumulation of snow and ice, that last all year long, that is thick enough to flow downhill under its own weight (gravity).
• A glacier
What are the 2 types of glaciers and what are examples?
mountain: piedmont glacier
Continental: Iceland
How do glaciers move?
Basal sliding
Plastic deformation
What’s the difference between the zone of accumulation and zone of ablation?
accumulation: area of net snow addition.
zone of ablation: area of net ice loss.
What is occurring in these zones during a time of glacial advancement, or glacial retreat?
If accumulation = ablation, the glacial toe stays in the same place.
If accumulation > ablation, the glacial toe advances.
If accumulation If accumulation
How do glaciers modify the landscape (erosional and depositional landforms)?
Erosion
Transport
Deposition
What causes the ice ages?
- Plate tectonics
- Distribution of continents toward high latitudes
- Oceanic currents
What is the Core?
Inner – Solid iron Outer – molten iron; magnetic field generated
What is the mantle?
Lower – rigid (solid); silicates rich in iron and magnesium Upper – more silicates
What is Moho?
Moho:Separates crust from upper mantle
What is the crust?
Oceanic (more dense) Continental (less dense)
Rigid rock comprising the crust (oceanic and continental) as well as the underlying rock
Lithosphere
Plastic or mushy upper part of the mantle
Convective movements in
this layer drive movements of the crustal plate
Asthenosphere
Amount of energy released in an earthquake
Magnitude
spot along fault where quake originates
Focus
point on surface directly above the focus
Epicenter
is based on amplitude of seismic waves, which is related to energy released.
Richter’s scale
How do glaciers form?
Snowfall accumulates and survives the following summer.
Snow is transformed into ice.
is establish a sequence of events without knowing exactly how long ago they occurred.
Relative
establish when an event took place in the past.
Absolute
Why is the hot inner core solid?
Increased temperature with higher pressure
Continental Crust is _____dense.
Oceanic Crust is _______ dense.
Less
more
vertical elevation difference in the landscape
Relief
the undulating form of the Earth’s surface, including its relief (topographic maps)
Topography
What are the three types of stress?
Tension (stretching)
Compression (shortening)
Shear (twisting and tearing)
is the breaking of rock without any chemical alterations
Physical weathering
is the decomposition of minerals that make up rocks by chemical processes
Chemical weathering
What are the process of denudation?
Weathering Mass Movement Erosion Transportation Deposition
what are the typical drainage patterns?
Dendritic:Branching or tree-like
Trellis: Trunk stream flows through resistant rocks, tributaries flow between ridges
deposition of sediments
*slower velocity (decreasing capacity and competency)
Aggradation
the removal of sediments and rock *faster velocity (increasing capacity and competency)
Degradation
lifting and removal of individual loose particles
Deflation
grinding of rock surfaces with a “sandblasting” action
Abrasion
What contributes to destertification?
Poor agricultural practices (e.g., overgrazing,
and other soil structure and fertility abuse) Improper soil-moisture management
Erosion and salinization
Deforestation
Ongoing climate change
Population increase
Lack of regulations and policy
a long-lived block of durable continental crust commonly found in the stable interior of a continent (“nucleus” on which continent “grows”)
Craton
Work of wind
Eolian
