What is the difference between a sea and an ocean?
Seas are smaller, shallower, saltier, and surrounded by land
What invention made accurate open ocean navigation possible by determining longitude?
Chronometer
What is a scientific theory?
An explanation for a natural phenomenon that is supported by many observations
Why does the Earth have a nickel-iron core at its center, surrounded by silicate mantel?
Core material is more massive, has higher density
Why is continental crust higher than ocean crust?
Continental crust is less dense than ocean crust
According to the Nebular Hypothesis, the Sun, Earth, and other planets in our solar system formed from an enormous cloud of gas and dust. What are the essential facts about the early Earth with respect to the following: existence of oceans, formation of E
Size of Protoearth was larger than today, there were no oceans/life, and the core had homogenous composition throughout (answer that is not true: atmosphere was mostly oxygen)
Continental and ocean crust have different levels because oceanic crust is denser and "floats" lower on the asthenosphere than continental crust because of isostasy. Assuming no difference in structure, what would happen if the two types of crust were mad
There would still be a difference because continental crust is thicker
Charles Darwin considered a career as a minister. What would have happened to the theory of evolution had he not become a scientist instead?
It would have been proposed around the same time by someone else
Radio-isotypes of Potassium (K40) decay to Argon (AR40). If a rock sample begins with 12 billion K40 atoms, what will the quantities of K40 and AR40 be after 1 half-life and 2 half-lives?
K40= 6 billion, 3 billion. AR40= 6 billion, 9 billion
What is the concept of isostatic adjustment and what topic in the chapter does it apply to?
Isostatic adjustment is the vertical movement of crust as a result of the floating lithosphere upon denser material beneath (asthenosphere)
What is the role of oxygen on Earth?
Our bodies need oxygen to burn food. Oxygen in the form of ozone protects Earth from most ultraviolet radiation (answer not true: it is essential for anaerobic bacteria's survival)
Alfred Wegener's theory of continental drift seems so reasonable today. Why was it rejected by a majority of scientists during the early 20th century?
Wegener was a meteorologist not a geologist, evidence supporting the theory was not available until 1950s, his driving mechanism was considered inadequate
Why are earthquakes mainly found at the edges of plates?
Plates rub together there
What happens when plate tectonics causes two continents to collide at a convergent plate boundary?
Neither subduct, but form large mountains instead
How does an ocean basin form?
A continental plate is pulled apart and seafloor spreading creates ocean lithosphere in the gap left between the pieces
What is the difference between an atoll and a guyot?
An atoll is at sea level and a guyot is below sea level
Transform plate boundaries are parallel to the relative motion between two plates. What would happen if the direction of the plate motion changed?
It would become either convergent or divergent depending on the direction of motion
You are exploring an ocean basin and trying to determine whether it formed by seafloor spreading. Which of the following evidence would you NOT expect to find in an actively spreading ocean?
Answer not true: Dredging would yield granite
Where do most of the largest earthquakes occur?
Convergent plate boundaries
The alternating reversals of Earth's magnetic field throughout history have been recorded in sea floor rocks in a particular pattern. How does this support plate tectonics?
The pattern of alternating reversals indicates seafloor spreading
Why are ocean ridges different from ocean rises?
Ridges are formed from slow spreading while rises are formed by fast spreading
In relation to plate tectonics, what is a major overall trend in earthquakes?
They occur at plate boundaries
Global temp rise increases the amount of cloud cover because of the higher moisture available in the atmosphere. These clouds then reflect incoming solar energy disallowing some of that energy to heat Earth's surface. In this way, the overall effect of in
Negative-feedback loop
Global temp rise is causing polar ice to melt. Because ice has higher albedo (reflects solar energy) than water, loss of ice cover increases heat absorption in polar regions. This accelerates ice melt. What term may be used to describe this process?
Positive-feedback loop
The general scientific consensus is that if levels of human cause emission continue to increase, what will happen?
Overall the Earth will get warmer and global distribution of climate patterns will change. Climate change is caused by human conditions
What does the Milankovitch cycle refer to?
It takes into account Earth's eccentricity, obliquity, and precession to explain climate variations
Why is it that a winter may be colder for one season if Earth is said to be experiencing global warming?
Climate can still be warming in the long term
Of all the human-caused gases, which gas makes the greatest relative contribution to increasing the greenhouse effect?
Carbon dioxide
What is causing the hole in the ozone layer?
CFC's
The basic idea of global warming is sunlight enters the atmosphere from space and is then transformed to what type of energy that is trapped by CO2 in the atmosphere?
Infrared rays
What is the record of CO2 in the atmosphere that has been collected from volcano in Hawaii?
Keeling curve
Although the concentration of CO2 has been going up steadily over the last 40 years, it always goes down during the period of April through October. Why is this?
Plants absorb CO2 during peak growth season
How could climate change affect the drinking water supplies of people in Asia?
By melting the Himalayan glaciers
The ice core records of Antarctica go back how many years?
650,000 years
Until the present time, the ice core records of Antarctica show that CO2 concentrations have never exceeded what level?
300 parts per million
Vice President Gore proposes that climate change may be causing more intense hurricanes. In terms of scientific knowledge, what kind of idea is this?
Hypothesis
What is causing the trees in parts of Alaska to lean over?
Melting permafrost
What is the average depth of the ocean in meters (to nearest thousand)?
4000 meters
What is a hypsography curve?
Percentage of Earth's surface at ranges of elevation or depth
What are the major marine provinces?
Continental margins, deep-ocean basins, and mid-ocean ridges
Why is the East coast of the US considered a passive margin?
It is far from any plate boundary and experiences no major plate tectonic activity
Why is the topography of the coastal continents similar to the bathymetry of the continental shelf?
The shelf is continental crust
What geologic feature would you expect to find at the down-slope end of steep walls of submarine canyons?
Multiple sorted layers of boulders, pebbles, and finer particles
Where would you expect to find ocean trenches?
Where ocean crust subducts under continental/ocean crust
Where would you be least likely to find an abyssal plain?
Pacific Ocean
What causes pillow lava to form?
A lava tube emits molten lava into the ocean
What are hydrothermal vent chimneys formed from?
Metal-rich minerals dissolved in hydrothermal fluid
What right-angle features connect parallel segments of mid-ocean ridges?
Transform faults
From smallest to largest, how should sediment textures be listed in the correct order?
Clay, silt, sand, pebbles
Why is quartz one of the most abundant constituents of lithogenous sediments?
It is extremely durable
The Calcite Compensation Depth (CCD) is the depth of the ocean where _______ equals ______.
Where carbonate dissolution equals carbonate supply
Why are gas hydrate deposits abundant on submarine continental margins?
There is a high temperature with low pressure
Why are the deep ocean basins covered with red clay deposits?
Absence of coarser lithogenous and biogenic particles
On the whole, what is the most important mechanism of transporting continental-margin lithogenous sediments?
Flowing water
You are on a research cruise and leave Japan, heading east. At about 1500 kilometers east of Japan you encounter a large volcanic plateau that is covered with sediments. You lower a piston core to sample the sediments and the wire indicator says 2500 mete
Carbonate ooze
Most biogenic sediments consist of tiny shells called microfossils that are made of what two substances?
CaCO3 (calcium carbonate) and SiO2 (silica)
Why is most lithogenous sediment composed of quartz?
Quartz is resistant to abrasion, it is extremely abundant, and extremely stable
How are oozes different from abyssal clays?
Ooze= 30% biogenous test material, Abyssal clay= 70% fine clay-sized particles
Why are gas hydrates important?
50 sites worldwide contain extensive gas hydrate deposits on the sea floor, could be a huge source in the future
Many of the unique properties of water, such as cohesion and its reputation as a universal solvent, come from its atomic structure. What causes these properties?
Water molecules are electrically polarized
What is the unit equivalent to raising the temp of 1 gram of water by 1 degree centigrade?
Calorie
Why does ocean temp change little from day to night?
High heat capacity absorbs solar energy quickly and releases it slowly
What does the principle of constant proportions tell us?
No matter the salinity of ocean water, the ratios of major dissolved ions remains the same
Which of the following processes is NOT part of the hydrologic cycle?
Answer not true: Water is added to the oceans and atmosphere by volcanic activity
How does the latent heat of evaporation (and latent heat of condensation) moderate climate?
By absorbing energy on evaporation and releasing it on condensation, it keeps water cool when the air is hot, and warm when the air is cool
Hydrothermal vents are considered both a source and sink for ocean salts. How can one factor both add and take away salt?
As water interacts with hot rock, some materials are dissolved while others are deposited
In the oceans, all of the following processes decrease local salinity except for one. Which process increases salinity?
Evaporation
How does water have such strong surface tension?
Hydrogen bonds form giving it a strong surface tension
Why do lakes like the Dead Sea and Great Salt Lake make floating objects so much more buoyant than they would be in seawater?
These waters are hypersaline; high amount of dissolved solids make it dense and buoyant
Water in the ocean combines with carbon dioxide to form a weak acid called carbonic acid, but the ocean's pH is 8.1 on average, which is slightly basic. How is this so?
Has its own natural buffer system
What causes most places on Earth to have seasons?
The spin axis is tilted 23.5 degrees to the plane of Earth's orbit, causing solar radiation to vary in angle as Earth revolves around the Sun
If you travel by plane from NY to Paris, which way do you have to steer to arrive in Paris airport?
Slightly north of a direct line to the airport
Why is ocean climate divided into latitude parallel zones that become progressively colder from equator to pole?
The average solar radiation (sunlight) striking the surface declines from equator to poles
What is the effect on surface winds of heating air at the equator?
Surface winds converge at the equator
A non-rotating Earth would have a single convection cell (wind belt) in each hemisphere. What is the result of Earth's rotation on formation of wind belts?
There are 3 wind belts in each hemisphere
Why is Florida in a tropical climate while Baja CA at the same latitude, is temperate?
Ocean currents bring warm water up from the tropics to Florida but down from northern latitudes to Baja
What causes ocean surface currents to form large gyres?
Barriers formed by the continents and wind blowing over the ocean
The Gulf Stream and the Brazil Current are examples of what?
Western boundary currents
What is the main cause of surface water sinking to cause the deep, thermohaline ocean currents?
Density increase caused by cold in polar regions, and density increase caused by greater salinity
In the Atlantic, North Atlantic Deep Water (NADW) sinks near Greenland and heads south along the ocean bottom. Antarctic Bottom Water (ABW) sinks off Antarctica and moves north along the ocean bottom. What happens when they meet?
ABW stays on the bottom, NADW overrides it