GEOL exam 2 Flashcards

Terms Definitions
longitudinal dune
odd-toed mammals
rhinoceros, horse
pro delta
shallow marine
clay
less than 1/256 mm
SMCLs
Secondary Maximum Contaminant Levels
-color/odor
Weathering
sediment/clasts are produced by mechanical weathering
creep
slow downhill movement of regolith
The Cretaceous/Tertiary (K/T) boundary layer worldwide has a high percentage of the element _______ in its clay,an enrichment about 300 times greater than the normal abundance
iridium
Wet climates produce _____ soils.
latenite
C horizon
partially altered parent material
spit
fingerlike ridge of sediment that extends out into open water
Acritarchs
An extinct group of apparently eukaryotic phytoplankton whose earliest representatives are in Proterozoic rocks
Compression:
At shallow levels deforms brittlely (fracturing or faulting). At deeper levels, hot enough to flow, ductile folds can form.
Aquifers
Water saturated sediments and rocks from which water can be withdrawn
Cross-bedding
• Individual beds are inclined to the horizontal• Can indicate current direction • Form with sand dunes, streams, deltas etc.
Fractional crystallization
The opposite of fractional melting:Substances with the highest melting points crystallize first, leaving a felsic rich magma
Cyclothems
Unique cyclic sediments. A specific type of deposition, 10 beds followed by another 10 beds between minor disconformities, then another 10 beds. Approximately 50 feet is a complete cyclothem. Cyclothem correlation is best to look at in Kansas and Pennsylvania. 
 
Deposited by transgressions and regressions. The origin of cyclothems is from repeating sea-level rise and fall due to glacial eustasy. 
 
Found in the Pennsylvania period. 
ophiolites
-distinctive rock sequences found in many mountain chains on land-the top layer consists of marine sedimentary rock and below lies a zone of pillow basalt which is underlain by a sheeted-dike complex that probably served as feeder dikes for the pillowed lava and layers
stress
force applied to a given area
What type of plant was the Rhynia?
vascular
granite-gneiss complex
gneiss from intense metamorphism with intrusions of granite
Genetic Drift
the gradual changes in gene frequencies in a population due to random events
superposition
When a marine geologist collects a core of undeformed ocean-floor sediment, she knows the youngest layer is on the top of the core and the oldest is at the bottom because of the principle of ______.
glacial trough
u-shaped valley formed by deposition of glacial sediments
ductile
able to be drawn into thin wires
Hardness
• Mohs hardness scale from 1 to 10.
Lava Chimneys
freezing lava against tree trunks which later rot away
Krakatau
small island between Java and Sumatra, became active in 1883, climatic phase in August. 4 large explosions, largest noise ever recorded! massive ash falls. everyone around the world knew, but it was not as serious as Tambora
Abrasion
River Erosion
sediment grains in flow sandblast rocks
-bedrock exposed in channels polished smooth
-potholes
losing stream
-occur in drier climates-streams that loose water to the saturated zone-the channels of these streams lie above the water table
rift zones
relatively narrow zones where seafloor spreading occurs
Oxide
nonsilicate mineral w oxygen and one or more metals
By what period do we have clear evidence for jawed fish?
Devonian
continental margin
that portion of the seafloor adjacent to the continents. it may include the continental shelf, continental slope, and continental rise
decompression
melting that takes place when a body of hot mantle rock moves upward and the pressure is reduced
Monocline:
nearly flat layers bend down (dip) in one direction and then flatten out again.
What is humus?
-Partially decayed organic matter in soil
-Can be seen if soil is looked at under a magnifying glass
Types of faults
Normal faultThrust (low angle) or reverse fault (high angle)Strike slip fault
Halekala
on Maui, last recorded eruption out of big island, 1690 Strombolian eruption, "house of the sun"
Geopressurized natural gas
gas dissolved in deep hot brines.
debris avalanche
a rapidly moving, turbulent mass of debris, air, and water
moment magnitude
the most objective way of measuring the energy released by a large earthquake
mass wasting
transfer of rock and soil downslope under the influence of gravity
how many elements make up 99.23% of earths crust
12
zone of accumulation
minerals leached from the E horizon accumulate here.
braided
A _____ stream flows in a network of rivulets (subchannels) around numerous sandbars.
What are the characteristics of a sandstone?
-Clastic sedimentary rock
-Medium-grained
-Clasts are typically, but not necessarily, dominated by the quartz grains
analagous traits
traits that are not the homologous but have similar functions
The last 50,000 years have seen the extinction of many large-bodied mammals. One of the probable causes is
human predation
Drainage, or Q =
wdv, width x depth x velocity
breaker
a wave that has become so steep that the crest of the wave topples forward, moving faster than the main body of the wave
What causes plate movement?
Slow convection in the solid mantle
What is a cuttoff?
The new shorter channel segment
stable platform
part of the craton that is mantled by relatively undeformed sedimentary rocks and underlain by a basement complex of igneous and metamorphic rocks
Steps of glacial formation
Snow is recrystallized into a much denser mass of small grains called firn. Once the thickness of the ice and snow exceeds 50 meters, firn fuses into a solid mass of interlocking ice crystals - glacial ice.
What are the significant affects associated with natural air pollution?
significant affects include - volcanoes- forest fires- dust storms- mold and pollen
ice sheet
a mass of ice that is not retricted to a valley but covers a large area of land
What is abrasion?
Rocks within the ice the act like sandpaper to smooth and polish the surace below
What is another important process in chemical weathering, and how does it occur?
-Oxidation, a reaction between minerals and oxygen dissolved in water
-Iron and manganese are present in many rock-forming minerals
-When these minerals undergo chemical weathering, the iron and manganese are released to solution and immediately combined with oxygen
-Oxidized iron commonly forms limonite (yellow) and manganese forms pyrolusite (black)
What are additive effects?
an additive effect is a result of interaction to air pollutant that lead to an irritant response like coughing.
What conditions causes readjustment of stream base levels?
raising the base level causes deposition, lowering base level causes erosion,changing its velocity changes the capacity a stream can carry
false (it must be inorganic)
a mineral must be organic (true or false)
What happens in a Continental Collision? CC colliding with CC?
• Neither of the CC are subducted, • Both are very buoyant and want to "float" or ride high.• This is where you form the very large mountain chains.• Mountain building• Earthquakes
Calcium deficiency is a problem in trees where ____.
the bedrock is quartzite or granite
3 factors that affect the rate of weathering
surface area, type of rock, climate
With respect to the greenhouse effect, the Earth’s atmosphere is
transparent to short- and opaque to long-wavelength radiation
why are rainforest soils so poor for farming?
because high rainfall leaches most of the soluble minerals from the soil, bacteria consume humus very quickly, results in very nutrient-poor soil
Meandering channels are found on ____ slopes, and have _____ and _____.
gradual slopes and have cut banks and point bars.
What did the lobe fins evolve into and why
limbs due to all the walking on land
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