Oceanography Exam 1 quilt
A rock has 1000 atoms of a radioactive isotope with a half-life of 500,000 years. After 1,500,000 years how many parent atoms will remain?
1.5 mill / 500,000 = 3 half lives 1000/2 = 500 500/2 = 250 250/2 = 125 answer is 125
How much wider is the Atlantic Ocean today than when Christopher Columbus sailed? Assume that the Atlantic Ocean is getting wider at a rate of 3 centimeters per year (about 1 inch). (Round off the dates to the nearest century to make the calculation simpler.)
15 meters (49 feet)
A rock has 2,000 atoms of a radio-isotope with a half life of 4 million years at time it was formed. How many atons of the daughter isotope exist after 8 million years.
15000
The oceans are believed to have formed about _____________.
4 Billion years ago
Approximately what percentage of the surface of Earth is covered by oceans?
71%
Which of the following is associated with a subduction zone?
A volcanic arc
In general, where can the youngest ocean floor be found?
At the mid-ocean ridge
Time in Greenwich is 10:20 AM when it is noon at your current location. What is your longitude?
Before 12 means east, 1hr and 40 min before 12. Multiply 1 hr x 15 degrees/hour = 15 degrees. 40 min is 2/3 an our x 15 degrees = 10 degrees. 15+10 = 25 degrees E
Based on the scientific method, science supports the explanation of the natural world that _____________.
Best explains all available observations
Which of the following statements about biogenous oozes is false? The organisms that form biogenous oozes live in the sunlit surface waters of the ocean. Biogenous oozes are composed of the hard remains of once-living organisms. Biogenous oozes are created by underwater eruptions, which cover the sea floor with fine ash particles. Biogenous oozes include sediments that contain at least 30% SiO2 tests. Biogenous oozes include sediments that contain at least 30% CaCO3 tests.
Biogenous oozes are created by underwater eruptions, which cover the sea floor with fine ash particles.
The steep transition zone between the outer edge of the continental shelf and the deep-ocean basin is called the ____________________.
Continental slope
What physical property determines the order of Earth's layers?
Density
Which of the following statements concerning density stratification is false? Outgassing is a direct result of density stratification. Density stratification is responsible for the structure (layering) within Earth. Density stratification has caused Earth to be homogeneous throughout. Density stratification is the tendency of heavy material to sink. Density stratification has caused the highest-density material to migrate to Earth's core.
Density stratification has caused Earth to be homogeneous throughout.
The East Pacific Rise is associated with which type of plate boundary?
Divergent
Plate boundaries where new oceanic crust is being added are called _____________.
Divergent Boundaries
Your job is to locate the world's plate boundaries. To do this, you may use only one map. The best map to choose for this job is a map that shows the worldwide locations of ___________________.
Earthquakes
Because they tend to move downslope, most lithogenous sediments are deposited in abyssal plains. True/False
False
Black volcanic beach sand is a type of hydrogenous sediment. True/False
False
The calcite compensation depth (CCD) represents the depth where wave action ceases to form calcareous oolites. True/False
False
Turbidity currents are highly erosive and are thought to be responsible for the creation of deep-sea trenches. True/False
False
Which of the following is not an important control on oceanic sediment accumulation Degree of preservation of biogenous sediment Proximity to river outlets Rate of biological activity Rate of sediment despositon Hydrothermal vents
Hydrothermal Vents
Why does the mid-ocean ridge have a zigzag appearance?
It accommodates spreading of a linear ridge system on a spherical Earth.
All of the following are examples of sediment-transporting media except ___________. Streams Wind Levitation Glaciers Gravity
Levitation
The GPS system is a tool used for determining surface __________________.
Location
Which of the following statements about manganese nodules is false? Manganese nodules are a type of foraminifer. Manganese nodules are thought to precipitate directly from seawater. Manganese nodules form in layers around a central nucleation object, such as a grain of sand or a shark's tooth. Manganese nodules are composed of oxides of manganese, iron, cobalt, and other metals. Manganese nodules are a type of hydrogenous sediment.
Manganese nodules are a type of foraminifer.
The cosmological model for the formation of the Sun and the rest of our solar system is called the ___________________.
Nebular Hypothesis
What happens when two continental plates converge?
Neither subducts; instead, a mountain range forms.
Which ocean is the deepest on Earth?
Pacific Ocean
Of the following, which best describes the physical property of the asthenosphere? gases liquid plastic rigid
Plastic - composed of hot rock material that has plastic properties (ability to flow slowly over time)
The major force transporting continental sediments to the ocean is
Rivers
Which of the following statements about the Deep Sea Drilling Project (DSDP) is false? The DSDP confirmed that the age of the ocean floor increases with distance from the axis of the mid-ocean ridge. The DSDP confirmed that Earth's magnetic field polarity reversals are recorded in sea floor rocks. The DSDP confirmed that sediment thickness increases with distance from the axis of the mid-ocean ridge. The DSDP drilled to the center of Earth and confirmed that the outer core is composed of liquid iron-nickel material.
The DSDP drilled to the center of Earth and confirmed that the outer core is composed of liquid iron-nickel material.
How is it that the ocean floor is so much younger than the ocean itself?
The ocean floor keeps regenerating itself
What happens to the ocean water over a seamount on the ocean floor when measured from a satellite?
The ocean water rises up to form a mound based on the mass of the seamount.
What happens when an oceanic and a continental plate converge?
The oceanic plate will be subducted
Which of the following statements about submarine canyons is false? They are found only off mountainous coasts. They are erosional features. They occur mainly on the continental slope. They have V-shaped valleys. They resemble canyons on land but are underwater.
They are found only off mountainous coasts.
Which of the following statements about fracture zones is false? They are transform plate boundaries. They are found beyond the offset segments of the mid-ocean ridge. They are ancient fault scars. They experience very little seismic activity. They are embedded within a plate and so are often referred to as "intraplate" features.
They are transform plate boundaries
The Hawaiian Islands are associated with which type of plate boundary?
They aren't associated with any plate boundary
Which of the following statements concerning graded bedding deposits is false? The particles within each graded bedding layer get progressively finer (smaller in size) as one moves upward. Each graded bedding sequence represents one turbidity current event. They result from successive lava flows. They are associated with submarine fans. They comprise part of a turbidite deposit.
They result from successive lava flows.
Which of the following tropical islands would likely be the youngest? tropical island without a fringing reef tropical island with a barrier reef ring-shaped tropical island (called a coral atoll) tropical island with a fringing reef
Tropical island without a fringing reef (coral reefs take time to build up)
All the continents could fit into the space occupied by the Pacific Ocean. True/False
True
Most lithospheric plates contain both oceanic and continental crust. True/False
True
Pillow lavas (pillow basalts) indicate that molten lava came in contact with water and cooled very quickly. True/False
True
The Andes Mountains, which are a tall mountain range along the west coast of South America, are associated with an active continental margin. True/False
True
The early oceans and atmosphere are thought to have come from inside Earth and were formed by a process called outgassing. True/False
True
The deepest spot in the ocean is deeper than Mount Everest is high. True/False
True, Mariana Trench
How is most sediment transported from the continental shelf out to the continental rise?
Turbidity currents
Lithogenous sedminetnts come from
Weathering of the continents
What was the main reason scientists objected to Alfred Wegener's idea of continental drift?
Wegener's proposed mechanism for movement was thought to violate the laws of physics.
Of the following, which is the best description of a sea floor hydrothermal vent? a chimney that emits hydrogen gas that occasionally ignites as a glowing torch a fault that provides a conduit for the release of clear, very cold water a bottomless crack through which lava pours out onto the ocean floor a chimney that emits a column of hot, cloudy water formed from the precipitation of metal-rich minerals a crack that releases only steam and smoke
a chimney that emits a column of hot, cloudy water formed from the precipitation of metal-rich minerals
Which of the following best describes a continental borderland? a mid-ocean ridge just beyond a narrow continental plain a series of islands, shallow banks, and deep basins a deep ocean trench just beyond a narrow continental slope a narrow shelf, leading out to an abyssal plain a wide, flat continental shelf with a steep continental rise offshore
a series of islands, shadow banks, and deep basins
Which of the following is the most fine-grained sediment? abyssal clay silt from a quiet lagoon cobbles on the beach a pebble beach beach sand
abyssal clay
The naturalist Charles Darwin, who is credited with developing the theory of evolution by natural selection, suggested that the changes organisms display through time are the result of _____________.
adaptations to different environmental conditions
Where would you expect to find well-developed continental shelves?
along passive continental margins
Where are most modern-day calcareous oozes found in the ocean?
along the mid-ocean ridge beneath warm surface waters
A small, rounded, submerged volcanic hill with a summit that is less than 1 kilometer (0.6 mile) above the sea floor is called __________________.
an abyssal hill
Where is the Ring of Fire located?
around the margins of the Pacific Ocean
The faster the rate of spreading at the mid-ocean ridge or rise, the ________ the underwater volcanic mountain range.
broader (wider)
Beneath the calcite compensation depth (CCD), ___________.
calcium carbonate dissolves in seawater
Which of the following is the most abundant component of deep-ocean sediments by weight? evaporites clay sand gravel fecal pellets
clay
Most chalk is made from ___________.
coccoliths
Populations of microscopic marine organisms in ocean surface waters closely match their abundance in sediments on the ocean floor, even though it takes 10 to 50 years for an individual particle to sink to deep-ocean depths. What accounts for this pattern?
concentration of the particles in fecal pellets.
Where would you NOT expect to find significant volcanic activity?
continental collision zone
If you could walk across the sea floor on a passive continental margin, heading away from shore, what is the order of provinces you would cross?
continental slope, shelf, rise (figure 3.9)
An ocean trench is associated with what type of plate boundary?
convergent
What process is primarily responsible for the formation of the continental rise along the East Coast of the United States?
deposition of sediment by turbidity currents as deep-sea fans
Bathymetry involves the measurement of the ___________.
depth of ocean floor below sea level
Which of the following marine organisms live in cold, polar waters? coccolithophores radiolarians diatoms foraminifers
diatoms
In sediments, what does the Wentworth scale describe?
grain size
Overall, the Atlantic Ocean basin is ________, and the Pacific Ocean basin is ________.
growing, shrinking (Atlantic is still undergoing sea floor spreading and pacific is shrinking because of oceanic plates being sub-ducted around it)
The vertical movement of crust to accommodate additional weight or removal of weight is called _____________.
isostatic adjustment
Lithogenous sediments are ___________.
made of material derived from pre-existing rock material
As a tool, the modern evidence from paleomagnetism has helped support plate tectonics by showing that ________________.
magnetic sea floor "stripes" are symmetric with respect to the mid-ocean ridge. fig 2.10
Which of the following gases was absent from Earth's early atmosphere? oxygen helium methane carbon dioxide hydrogen
oxygen - used to be a waste from plants
The continental margin of the U.S. Atlantic coast is a ____________ continental margin, and the continental margin off the west coast of South America is a _____________ continental margin.
passive, convergent-active
The most accurate scientific estimation of Earth's age is based on _____________.
radioactive methods of determining the age of meteorites and moon rocks
Ocean depths are routinely determined by ___________.
sending sound through water and determining time required for it to return to the ship
What best describes the tectonic setting of the Cascade Mountains of the Pacific Northwest?
subduction zone (continued volcanic activity)
Microscopic shells that create biogenous sediment on the sea floor are called ___________.
tests
The Age of Discovery was the time period in ocean exploration history when _____________.
the Western-European World realized the vastness of Earth's water-covered surface.
The only way for siliceous ooze to be preserved in the ocean is ___________.
to have it accumulate faster than it dissolves
The San Andreas Fault is associated with what type of plate boundary?
transform
Which of the following features is not associated with the crest of the mid-ocean ridge? SHOW HINT deposits of metal sulfides hydrothermal vents pillow lavas a central rift valley trenches
trenches (associated with convergent boundaries)
Calcareous ooze is associated with ________ surface water conditions, and siliceous ooze is associated with ________ surface water conditions.
warm; cool
The subdivisions of the geologic time scale _____________.
were initially based on fossil evidence, extinction, and boundaries of early sedimentary rocks (this is before radiometric age dating)
