Earth Science Lab Exam 1
velocity
the rate of change of the position of an object -units of distance divided by units of time -like meters per second (m/s)
geologic time
4,570,000,000 or 4.57x10^9
mid-ocean ridge
An underwater moutain chain where new ocean floor is formed
volume
The amount of space an object takes up
subduction zone
The region where oceanic plates sink down into the asthenosphere.
earth atmospheric pressure
1.03 kg/cm2
heat energy
a form of energy that is transferred by a difference in temperature
Energy from earth's systems comes from
-earths internal heat, which melts rock, causes earthquakes, and builds mountains -xternal energy from the sun -the pull of gravity
processes in the rock cycle can change
-igneous rocks into sedimentary -metamorphic into sedimentary -sedimentary into different sedimentary
Was the constant rate for 50 million years? Measure the offset of the 30-Ma marble. Approximately how many kilometer has the marble been offset?
-measured the distance btw the offset marble layers as 22mm. -measure 100km on the scale as 7mm -set up a ration to find the distance btw marble layers 22mm/7mm=d/100km -cross-multiply: 22mm x 100km = 7mm x d -2,200 km / 7 =310
The reason quartz is one of the most abundant minerals is
-resistant to weathering -made of the two most abundant elements in the Earth's crust -can form in igneous sedimentary, and metamorphic
pressure
1 bar= 1 atm
Measure the amount of offset of the 50-Ma granite body. How many km has the granite body moved?
1)measure the distance between the same edges of the offset bodies (from one western edge to the other western edge) 2) convert measured distance to km using the scale provided 3)distance equals=77mm 4)100km on scale = 7mm 5) set up ratio to find the distance between bodies (77mm/7mm)=(d/100km) 6)cross-mutliply to solve for d: (77mm) x (100km) = (7mm)d 8) d= 7,700km/7 = 1,100km
the rate of submergence is the total change in the elevation of the pier divided by the total amount of time involved and is therefore how many cm per year? (1m=100cm)
2m 2m/300yr = 200cm/300yr =.67cm/yr
Lithosphere plates (plates)
12 major
how long is the bar scale representing the flea?
13.5 mm
How many times larger is the dog than the flea? dog=1m flea=1mm
1m = 1000mm dog is 1000x larger
Assume that the flea in the image on p.15 is 1mm long and the dog is 1m long. to relate this to our English system of measurement, how long is this flea in inches?
1mm x (1cm/10mm) x (1in/2.54cm) = 1 in/ 25.4 = .04 in
Repesent geologic time with a 24hr clock
24 h = 1 d = 4,570,000,000 24hr in 1 day 24x60 = 1,440 min 1,440x60= 86,400 sec (4.57x10^9)/86,400= 52,894 yr/sec 52,894x60= 3,173,700 yr/min 3,173,700 yr/minx60 = 190,422,000 yr/hr
Now consider a problem the rate of submergence might solve: a local restaurant owner is considering the purchase of a pier that is 50 cm above the high-water mark for use in outdoor events. He has been advised that piers less than 30 cm above the high water mark should be avoided. If submergence continues at the rate you calculated, how many years will he have until the high water mark is less than 30 cm from the base of the deck?
30 years: The pier will have to be submerged 50-30=20cm for the high water mark to be less than 30 cm. (depth of submergence(d) = rate of submergence(r) x time(t)) d=rt 20cm=(.67cm/yr)t t=(20cm)/(.67cm/yr) = 30 yr
gravity
A force of attraction between objects that is due to their masses.
weight
A measure of the force of gravity on an object
magma
A molten mixture of rock-forming substances, gases, and water from the mantle
transform boundary
A plate boundary where two plates move past each other in opposite directions
Lithosphere
A rigid layer made up of the uppermost part of the mantle and the crust. (100 to 150km)
the scientific method
A series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions. (observe, recognize that a problem exists, collecting data, proposing tentative answers to those questions-hypothesis, test, continue to test and make conclusions)
Matter is stored in the Earth System in five major reservoirs
Atmosphere, Cryosphere, hydrosphere, geosphere, biosphere
What kind of plate boundary occurs along the west coast of South America
Convergent
granite vl=78.3cm3 mass=207.5 g basalt vl=56.2cm3 mass=168.6g What is the densities of the two rocks?
Density= mass/volume granite- 207.5g/78.3cm3=2.65 g/cm3 basalt- 168.6g/56.2cm3 = 3.00g/cm3
Principle of Uniformitarianism
Earth processes occurring today are similar to those that occurred in the past
Passive continental margins include whihc of the following coasts?
East coast of SA, east coast of NA, all coasts of Australia
T/F: The west coast of Africa is a plate boundary
False
Which direction is LA moving relative to San Fran?
LA is moving northwest toward San Fran along the San Andreas Fault.
continental arc
Line of volcanoes on a continental plate; the volcanoes are on a continent above a subducting oceanic plate.
The lithosphere of the Atlantic Ocean forms at the boundary between which two plates?
North America and Eurasia
What is the name of the plate that the U.S. resides?
North American Plate
Does the North American Plate consist of continental lithosphere, oceanic lithosphere, or both?
The NAPlate consists of both cont. lithos and oceanic lithos
Chemical bonds
The atoms in compounds are held together by
seafloor spreading
The formation of new ocean crust as a result of magma pushing upward and outward from Earth's mantle to the surface.
Mantle
The layer of hot, solid material between Earth's crust and core.
bedrock
The solid layer of rock beneath the soil
Which coast would you expect to have the most earthquakes and why?
The west coast of South America should ahve the most due to active subduction zone
Continental Lithosphere
is thicker than oceanic lithosphere
Active continental margins include which of the following coasts? (p.53)
West Coast of South America, West Coat of NA, East Coast of Asia
volcanic island arc
a chain of volcanic islands generally located a few hundred kilometers from a trench where there is active subduction of one oceanic plate beneath another
deep-ocean trench
a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
geologic cycle
a material moves among several reservoirs but returns to the first
along the coast, waves carry sand out into deeper, quieter water, where it accumulates and gradually becomes buried. A rock formed from sand grains cemented together is
a sedimentary rock
possible origin of a metamorphic rock
a sedimentary rock is buried deeply beneath other sedimentary rocks
atmosphere
a semi-transparent blanket composed of about 78% nitrogen, and 21% Oxygen, minor amounts of CO2, water vapor, ozone (O3), and methane.
flux
a state of continual change or movement (the movement of material from one reservoir to another is called flux
the earth system
all of the matter, energy, and processes within Earth's boundary
compounds
atoms combine with one another chemically to form compounds; the smallest possible piece of a compound is a molecule
oceanic crust
both thinner and denser than continental
cryosphere
continental and mountain glaciers, polar sea ice
A sample of water has a volume of 5m and a mass of 4.985 g at 25C. What is the density of water at this temperature? (1ml = 1cm3)
d=m/v 4.985g/5.00ml = d= .997 g/cm3
If the fault blocks moved at a constant rate for the past 50 million years (myr), what is the approximate rate of offset?
d=rt r=d/t r= 1,100km/50myr = 22km/myr = 22/10^6yr r= 22km/10^6 x 1,000m/km x 1,000 mm/m = 22mm/yr
Assume that the fault blocks moved at a constant rate for the past 30 million years. What is the approximate offset rate?
d=rt r=d/t r= 310km / 30myr = 10km/myr = 10km/10^6yr r= 10km/10^6 yr x 1000m/km x 1000 mm/m = 10 mm/yr
density of granite to the density of basalt?
density of granite/density of basalt 2.65 gcm3 / 3.00 gcm3 = .883
chemical formula
describes the combo of atoms in a compound
Theory of Plate Tectonics
explains our outer layer of Earth as a group of separate plates that move with respect to each other an change the Earth's surface as they move
how large would the drawing of the earth have to be, if it were drawn at the same scale as the geologist? (answer in km and miles)
geologist bar = 4.4cm 6,400,000 x 4.4 = 28,160,000cm 28,160,000 cm = 281,600m = 281.6 km 281.6x(0.6214 mi/km) = 175 mi ANSWER: 281.6km/175mi
how many times larger than the geologist is the Earth?
geologist=2m earth diameter=12,800km 12800km/.002km =6,400,000x larger
Thick flows of glowing red lava engulfs farms and villages on the flanks of Mt. Etna, a volcano in Sicily. The cold, black rock formed when these flows are cool enough to walk on is
igneous rock
rocks formed fromthe cooling and solidification of lava molten rock are
igneous rock
formula for volume
length x width x height
Density
mass/volume -the more mass packed into a given volume of matter
The broad tundra plains of northern Canada expose gray, massive rock that formed many km below a mountain belt. This rock, exposed only after the overlying rock was stripped away, is
metamorphic rock
preexisting rocks subjected to conditions dramatically different from those in which they first formed, such as those that exist deep within the Earth under a mountain belt are
metamorphic rocks
In identifying a rock, a geologist must consider its
mineral content and texture
In clastic sedimentary rock
mineral grains can come from many different previously existing rocks
data
more observations and/or measurements
Biosphere
part of Earth in which life exists including land, water, and air or atmosphere
lithostatic pressure
pressure caused by the weight of overlying rock, increases as you go deeper in the geosphere and is great enough in the upper mantle to change the graphite in a pencil inot diamond
divergent plate boundary
plates move away from one another at the axis of submarine mountain ranges (mid-ocean ranges). molten material rises from the asthenosphere to form new oceanix lithosphere at the ridge axis. The ocean grows wider through this process, call seafloor spreading. through this the new lithosphere moves outward from the axis to the flanks of the ridge
orders of magnitude
powers of 10
hydrostatic pressure
ppressure caused by the weight of water, increases as you descend into the ocean and can crush a submarine in the deep ocean
kilobars
pressure is measured in 1 Kbar = 1k bars
geobaric gradient
rate at which lithostatic pressure increases
How long would the bar representing the dog have to be, if the dog were shown at the same scale as the flea? dog=1m flea=1mm
since the dog is 1,000 times larger than the flea the bar representing the dog would have to be 1000x13.5mm =13,500mm (13.5m)
atom
smallest piece of an element that still has all the properties of that element
igneous rocks form by
solidification of magma at the surface or within the Earth
element
substance that cannot be broken down chemically into other substances
San Fran and LA are on opposite sides of the SanAnd Fault. If the SanAnd is undergoing offset at teh rate that you calc in part e for the past 30mill yrs, how many will it take efore the two cities are directly opposite one another? distance btw SF and LA is 450km
t=d/r= 450km/10kmmyr =45myr
mass
the amount of matter in an object
geosphere
the solid earth the outer layer-the crust:relatively thin, like an eggshell, consists mostly of rock below crust-the mantle: mostly of diff kinds of rock and contains most of earth's volume the core: consists of mostly a liquid alloy of iron and nickel
A triple junction
three plate boundaries intersect
convergent plate boundary
two plates move toward each other
sediment
unattached mineral grains like boulders, sand and clay
plate boundary
where two plates meet
Asthenosphere
zone in the upper mantle, solid low rigidity that it can flow like soft plastic