Geology & Earth Systems Exam 1 (UMD)

What are the factors that influence environmental impact?

# of ppl X per capita rate of consumption of resource X pollution per unit of consumption = environmental impact

What are the 4 main types of metamorphic rocks and what plate tectonic settings are they found in?

- regional: compressional stress due to mountain building leads to high pressures and temperatures - high pressure: the metamorphism that occurs when a plate is subducted - contact: heat from nearby magma bodies transforms surrounding rock - hydrothermal: rocks may transform due to reaction with hot circulating fluids

What are the 5 processes that lead to breakdown of rock, deposition of sediment, and solidification of the sediment into sedimentary rock?

- weathering - erosion and transport - deposition - lithification - sorting

What are the possible forms of energy?

-Mechanical (kinetic and potential) - Thermal - Chemical - Radiant - Gravitational - Magnetic - Electrical

What is the thickness of the oceanic crust?

5-7 km (avg. 7km)

What does it mean to be in steady-state?

A system is said to be in steady state when the stock remains constant even if the particular atoms making up the stock are changing (flux in equals flux out)

normal fault

A type of fault where the hanging wall slides downward; caused by tension in the crust

How do we know the chronology of the solar nebula and early solar system?

All of the planets orbit the sun in the same direction, and have the right characteristics for their locations.

intermediate extrusive rock

Andesite

What is Bowen's reaction series and how does it relate to ultramafic, mafic, intermediate, and felsic rocks and where they are formed in the earth?

It describes how mafic magmas can be come more felsic by crystallizing and separating from mafic minerals

What are the different kinds of volcanic hazards?

Lahar, tephra, pyroclastic flow, debris, lava flow

What are the planets in the solar system?

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

What are the common elements in the crust?

Oxygen, Silicon, Aluminum, Iron, Calcium, Sodium, Magnesium, Potassium

extrusive igneous rocks

Rocks erupted by volcanoes cool rapidly and grow only small crystals

intrusive igneous rocks

Rocks that cool underground cool more slowly and grow big crystals

How are p-waves and s-waves different?

S-waves travel at half the speed of P-waves

What is fractional crystallization and how does it affect the change in mineral composition as a pluton solidifies in place?

When cools slowly big crystals form, when cools fast, small crystals form, gases become concentrated then dissolved, then makes bubbles

What are reservoirs?

a container for a particular material

What is the difference between a theory, a hypothesis, and a Law?

a hypothesis is developed into a theory and a law is a mathematical description of a phenomena that always behaves under the same conditions

What is the difference between prediction and forecasting?

a prediction is like calling it, and a forecast is a statement about the likelihood of an earthquake

strike slip fault

a type of fault where rocks on either side move past each other sideways with little up or down motion

Post-seismic

adjustment to the new stress state following an earthquake

intermediate rocks

andesite and diorite

What is a mineral?

are naturally occurring, generally non- organic solids with a definite composition and repeating crystalline structure

What is an ore mineral?

are those minerals that have economic value and can be mined profitably

Why do sedimentary clastic rocks become sorted by size?

because of the strength of the current, when in weakens the bigger rocks stop sooner than the small ones

Why are ores with sulfides in them more environmentally hazardous than ores without sulfides?

because the sulfides make the water in the mines acidic

convergent boundaries

boundaries where plates are moving together and old crust is destroyed

divergent boundaries

boundaries where plates move apart as new crust is formed

Transform boundaries

boundaries where plates slide past each other laterally

What is a subsidiary fault?

branch from the main fault.

How did the Himalayas form?

collision of India and Eurasia

P-waves

compressional or longitudinal waves, work by compressing the material they pass through

What factors influence the value of an ore deposit?

concentration, abundance

What are stocks?

content of a reservoir

What are the chemical layers of the geosphere and what are the main chemical elements in each?

crust; (O, Si) mantle; (O, Mg, Fe, Si) core; (Fe, Ni)

What are the physical layers of the geosphere and what are their physical characteristics (brittle, ductile, etc.)

crust; brittle, ductile, liquid lithosphere; brittle, solid asthenosphere; ductile, solid mesosphere; solid outer core; liquid inner core; solid

What evidence demonstrates that subduction is happening?

deep earthquakes (200km)

Mercalli Intensity Scale

describes the effects an earthquake has had on people, structures, and the land surface and is qualitative

ultramafic intrusive rocks

dunites, peridotites and pyroxenites; low silica content

aseismic

earth fault slip movement that doesn't produce any seismic shock

Which planets have Geospheres? Atmospheres? Hydrospheres? Pedospheres? Biospheres?

earth; all venus; atmosphere mars; atmosphere, hydrosphere, cryosphere, lithosphere mercury; atmosphere neptune; hydrosphere

Open system

exchanges energy and matter with its surroundings

closed system

exchanges energy but NOT matter with its surroundings

Isolated system

exchanges neither energy. nor matter with its surroundings

What are fluxes?

flow of a material in and out of a reservoir through (flow rate)

non-clastic sedimentary rocks

form from chemical reactions, chiefly in the ocean

What is a metamorphic rock?

form when igneous, sedimentary, or other metamorphic rocks transform to a new type of rock due to changing pressure and temperature and/or reacting with a fluid

What are clastic sedimentary rocks?

form when rocks are weathered, eroded from the land surface, transported, deposited, and lithified

What are the major earth systems?

geosphere (rock) pedosphere (soil) hydrosphere (water) atmosphere (air) biosphere (life) cryosphere (ice)

What is the difference between glass and a mineral?

glass has a disordered structure

What are geologic hazards and risks and how are they different?

hazards are any natural event that can have negative affects on life, property or environment, and the risk if what may happen from a geological hazard

What are the three main types of rocks?

igneous, sedimentary, metamorphic

What is the difference between copper and iron mining in Northern Minnesota?

iron is no longer being produced, and copper is

What determines hardness?

is a measure of how easily a mineral structure can be damaged

What is a concentration factor?

is the factor that one must multiply the crustal abundance of an element by to get a concentration that is profitable to extract

What is apparent polar wander, and why is it only apparent?

is the perceived movement of the Earth's paleo-magnetic poles relative to a continent while regarding the continent being studied as fixed in position

What kinds of growth do we encounter in Earth systems?

linear, & exponential

What was the evidence that convinced scientists of seafloor spreading (that is, what evidence did Wegener NOT have that led to the acceptance of the unifying theory of plate tectonics in the 1960s)?

magnetic striping, & rocks further from the ridge should be older and also covered by deeper sediment piles

What triggers eruptions?

mantle contains dissolved gases, magma has dissolved volatiles when gas comes out

What are hot spots and what do they create in oceanic settings?

mantle rock sitting just above the hot molten outer core heats up until it becomes buoyant enough to rise through the mantle - the plume This plume makes a pathway for hot buoyant material to rise, and can remain stable for many millions of years Makes islands

Where do volcanoes form?

most are at MOR, one above ground are by subduction zones & hot spots

interseismic

motion along the faults transfers stress until the elastic limit of part of the fault is reached

Coseismic

motion occurs along the fault as energy is released during an earthquake

How are minerals made?

naturally occurring

How are perpetual, potentially renewable, and non-renewable resources different?

non renewable cannot be replaced, potentially renewable can be replaced if used with time, perpetual cannot be depleted no matter the usage

Is earth an open, closed, or isolated system?

open, but sometimes acts like a closed system

Differentiation

process of the separating of a young planet into layers

What is reinforcing feedback?

processes result from a change in a system and also promote that change

What is a balancing feedback?

processes result from a change in a system that work against that change

reverse fault

reverse faulting is caused by compressive forces that squeeze and shorten a rock

moment magnitude

scaledescribesthe amount of energy released from an earthquake and is a quantitative measurement taking into account movement along the fault and strength of the rock

S-waves

shear or transverse waves, vibrate perpendicular to the direction that they are propagated, work by vibrating the medium back and forth

What are the different kinds of volcanoes? Where do they form? What is their eruptive style? Are they mafic or felsic?

stralovalcano; felsic hot spot; Hawaii shield volcano, mafic

what affects magma viscosity?

temp rises viscosity goes down vise versa

What is energy and how is it conserved?

the ability to do work; conserved over time, cannot be created nor destroyed

What is a reserve?

the known quantity of a resource that can be economically recovered

What is viscosity and how does it relate to eruption styles?

the resistance to flow; if gasses are still in the magma it is more runny

How can we use p-waves and s-waves to determine distance from a seismometer to an earthquake?

the seismometer will feel the P-wave first, then the s-wave, and then surface waves, if you know the speed of the waves and time intervals between arrival you can calculate the distance.

What is the rock cycle?

the series of processes that change one type of rock into another type of rock

What were Wegener's lines of evidence for continental drift?

visual fit fossil evidence rock evidence

Stream bank erosion

washing away of soil from banks of streams and rivers

What was Pangea?

when the continents drifted together to form a supercontinent

Why are there seismic shadow zones? How do we know that the outer core is liquid?

where the earthquake doesn't pass through; we know the middle core is liquid because s-waves do not pass through liquids

What is a supercontinent cycle?

• Continental collisions lead to supercontinents • Rifting breaks them up again • Has happened 2 to 4 times in Earth's history • Another supercontinent will likely form in the future

Felsic rocks

• Extrusive felsic rocks are rhyolites; intrusive felsic rocks are granites • These rocks can form from fractional crystallization of a mafic magma • They also occur when continental crust gets hot enough to partially melt • This can happen deep inside mountain belts Rhyolite & Granite

mafic rocks

• Extrusive mafic rocks are basalts and intrusive mafic rocks are gabbros • These rocks form by partial melting of the mantle • They make up the oceanic crust • Basalts erupt at mid-ocean ridges, at hot spots, and in volcanic arcs Basalt & Gabbro

What are Earth's sources of energy?

• Solar radiation • Primordial heat • Radioactive decay • Gravity

How do elastic and brittle deformation relate to earthquakes and cycles of stress and strain?

• Stress builds up along a fault • There is some elastic deformation • The elastic limit is exceeded • There is a release of energy as the fault fails brittly (the earthquake) • Each side of the fault rebounds and stress is reduced • This is called stick- slip behavior

How long did it take the planet to go from a big molten ball to a planet with differentiated layers?

4.5 billion

How much time passed between the last supernova injection into the solar nebula and the contraction of the solar nebula?

4.6 billion years

What causes melting in the mantle?

Decompression, the mantle has high pressure so when the pressure decreases the mantle melts

How did the solar system form?

Gravity pulled a cloud of gas and dust together, spinning fast, most of the matter condensed into the sun, the rest of the gas started to cool and condense into solids, when bumped into each-other it formed the planets

What are the two factors that affect what kinds of metamorphic rocks that form?

-What kind of rock did it start as? -How much heat and pressure did the rock experience?

What are the different kinds of deformation?

-elastic -plastic -ductile

What is the thicknesses of the continental crust?

10-70 km (avg. 35km)

How much time passed between the beginning of the contraction of the solar nebula and the formation of the solar system?

13.2 billion years

What determines cleavage?

Cleavage describes when a mineral tends to break along planes of weakness in its structure