smaller, rounder, better sorted and dominately resistant minerals
As sediment is transported downstream, away from its points of origin, the particles become:
Mineral calcite
Fossiliferous limestone, chalk, micrite and aragonite all have to do with
Doesn't have to do with mineral calcite
Avalanche on a submarine slope
If you find graywacke in the place where it formed, you know you are looking at ancient
Obvious sandstone beach deposits overlain by marine mudstone indicate transgression of the sea
Diagnosis and metamorphism both alter the texture and mineral composition of rock; metamorphism is the more extreme process
Sedimentary rocks form only at or near Earth's surface, never at gear depths
Rift basin
A Sedimentary basin that forms when continental lithosphere is stretched, causing down dropped crystal blocks bordered by narrow ranges and alluvial fans, is called
Sedimentary rocks can form by the precipitation of minerals from water solution, by the cementing together of loose grains of preexisting Rock and from shell fragments of carbon rich relicts of plants
A rock with a large, angular fragments and lots of feldspar is classified as immature; a rock with smaller roadbed grains and not much feldspar is classified as mature
The words weathering and erosion are synonyms
Glacial valley
What is most logical past environment to have produced a deposit consisting of layers of unsorted, unstratified sedimentary clasts, clay sized to Boulder sized ?
Could suggest an ancient stream bed or a seashore
Ripple marks on a bedding plane
Sand dunes
What is the most logical past environment to have produced consisting of layers of well sorted sandstone with cross beds several meters high ?
Chemical sedimentary rocks are crystalline in texture
Gypsum and halite are evaporate minerals
Flint, jasper, agate, and petrified wood are all varieties of the silicosis rock chert
Both Chert and limestone may have either chemical or biochemical origin
Major classes of sedimentary rocks
Clastic, biochemical, chemical and organic
The formation of dolostone, due to the introduction of magnesium into limestone is an example of diagenesis
What word is associated with the formation of tavertine ?
What sedimentary features is the surest indicator that the past environment was subaerial not submarine ?
Mud,slit, sand
Proper listing of detritus terms, going from smallest to largest
ripple marks created by water flowing from A to B
the diagram below is a profile of
Sedimentary rocks differ from igneous rocks in that sedimentary rocks can never be crystalline in texture and igneous rocks always are crystalline.
biochemical; limestone
Rocks formed dominantly from the calcium carbonate shells of marine organisms are classified as _____ and called _____ .
Graywacke and conglomerate are examples of well-sorted rocks; shales and fine-grained sandstone are examples of poorly sorted rocks.
oil shale
The organic sedimentary rock that is composed of mud-sized particles and partially decayed organic matter derived from plankton and algae remains is:
shallow-water carbonate area
What is the most logical past environment to have produced a deposit consisting of very little sand and mud, but instead lots of broken-up carbonate shells of marine organisms?
The presence of mudcracks indicates the sediments lithified in water.
A clastic sedimentary rock with clay and silt-sized grains that breaks in thin sheets is called:
A nonmarine clastic sedimentary rock composed of angular fragments surrounded by matrix is:
Columbia River Plateau, Washington
Which geologically special areas is not the result of sedimentary processes?
Sediment filling a passive margin basin can accumulate to more than 10,000 meters thickness.
Diagenesis is a general term used to describe all the physical, chemical, and biological processes that make a sedimentary rock from sediments.
bedding layers that have been churned by burrowing creatures like worms and clams
Geologists find evidence of bioturbation in an area of sedimentary rock. This means they must be looking at:
When sea level rises, the shoreline migrates inland, flooding the land and depositing coastal sediments over preexisting terrestrial sediments. This process is called:
mpaction and cementation of loose particles to form solid rock
Formation of a clastic sedimentary rock involves five stages. Which of the following describes lithification?
scour marks, fossil footprints, graded bedding, and mud cracks
Which of the following features indicates the top of a sedimentary bed, or bed-surface marker?
A sequence of sedimentary beds, distinctive enough to be recognized as a unit called a stratigraphic formation, gives clues to the past environment that produced it.
a delta
The structure that may form where a stream enters a lake
has nearly horizontal topes beds composed of gravel; has sloping forest beds of gravel and sand; has nearly horizontal silty bottoms beds on the lake floor
Pieces of broken rock produced by physical weathering are collectively called clasts or detritus.
current direction
Ripple marks, dunes, and cross bedding are useful indicators of:
The presence of redbeds indicates sediments lithified in water, which caused the iron to rust.
510 years
Examining sedimentary bedding in a geologic study reveals disrupted layers formed 260, 820, 1,200, 2,100, and 2,300 years ago. What is the recurrence interval of the earthquakes that caused the disruption?
Although the risk is small, disastrous earthquakes can happen in regions that are not seismic zones.
Rayleigh seismic waves cause Earth's surface to move vertically; love seismic waves cause the ground to ripple back and forth, creating a snake-like movement of the surface.
350 mi
Interpret the travel-time curve shown. How far away is the earthquake epicenter? (picture )
upper line A
Interpret the travel-time curve shown. Which line on the graph represents the S-wave? (picture)
Seismographs are only sensitive enough to record ground movements down to about one millimeter
Which term does NOT denote a pattern of motion of the Earth during an earthquake?
Friction occurs between sliding surfaces because no surface can be perfectly smooth; all contain small bumps or protrusions.
Friction occurs between sliding surfaces because no surface can be perfectly smooth; all contain small bumps or protrusions.
Earthquake magnitude scales all run from one (minimum amplitude) to ten (maximum amplitude).
the velocity of a tsunami wave increases when the wave moves from open ocean into shallower water.
Upthrust of the sea floor along a fault can displace huge amounts of water and result in giant tsunami waves.
what magnitude earthquake would have almost 33,000 times the energy release of a 4.2 quake
ground shaking
Which of the following earthquake phenomena is the least likely to actually injure or kill humans?
If a rock undergoes enough stress to produce elastic strain, an earthquake always happens.
Because intraplate earthquakes are infrequent and tend to have shallow hypocenters, they have had little effect on human society.
Induced seismicity can happen in an area when a reservoir is built, leaks, and introduces water into existing fault planes.
Interpret the travel-time curve shown. What time did the earthquake occur? (picture)
plate boundaries
Earthquake prediction is not highly reliable, but geologists do know more earthquakes happen along
Roughly 80% of the earthquake energy released on Earth comes in the continental collision zone where the Himalayas are still growing; the remaining 20% is scattered at random locations worldwide.
fault creep
releases stress gradually, and with no stress buildup, there are no quakes
Plotting the hypocenters (foci) of earthquakes, showing their progression from shallow to intermediate to deep as you move eastward across South America, is really drawing the profile of a subducting ocean plate.
R and L waves
surface seismic waves
The New Madrid, Missouri, quakes of 1811-1812 and the Charleston, South Carolina, quake of 1886 were both large intraplate quakes.
are usually along the boundaries of crustal plates.
The locations of major earthquakes and volcanic eruptions:
short term earthquake prediction
is being worked on but us far from being a successful produced; may inlay interpretation of swarms of foreshocks; may involve precise laser survey of the ground looking for small distortions; may be improved
may be just a broad, gentle swelling out at sea but grows as it approaches shore
long term earthquake prediction
based on the identification of seismic zones; are based on the study of historic recurrence intervals; involve looking for sand volcanoes and disrupted bedding in the area; involve looking for young fault scarps in the area
can cause clay-rich sediment to turn into an unstable slurry of clay and water; is the sudden loss of strength of some soils that happens because of earthquake shaking ;caused great damage in the Alaska quake of 1964;can affect sand layers below ground surface and cause them to erupt as sand volcanoes or sand boils
Interpret the travel-time curve shown. How many minutes between the arrival of the first P-wave and the arrival of the first S-wave? (picture)
Governments are supportive of the worldwide seismic network because it can detect nuclear bomb tests as well as natural earthquakes.
the Ritcher scale
measure quake size in terms of the ground motion it generates
It takes less energy to activate an old fault than to create a comparably sized new one, so old faults must still be treated as areas of weakness vulnerable to earthquakes.
Intermediate and deep-focus quakes occur in the Wadati-Benioff zone of divergent plate boundaries.
earthquake resistant structures
Concrete blocks crack and tumble; wood-frame construction flexes and has a better chance of surviving quake shaking.
blind faults that don't intersect the surface can cause earthquakes in unexpected places.
Block X is the hanging wall
On the diagram shown: (picture)
Resonance is the enhancement of motion of swings on a playground (or of buildings swaying during an earthquake) when a new push (or wave) arrives at just the right time to be "in sync" with existing motion.
thrust fault
A gently dipping reverse fault; the hanging-wall block moves up the slope of the fault. (page 358)
reverse fault
A steeply dipping fault on which the hanging-wall block slides up. (page 358)
normal fault
A fault in which the hanging-wall block moves down the slope of the fault. (page 358)
Earthquake activity. (page 289)
The amount of movement or slip across a fault plane.
The series of smaller earthquakes that precede a major earthquake
The series of smaller earthquakes that follow a major earthquake.
Richter scale
A scale that defines earthquakes on the basis of the amplitude of the largest ground motion recorded on a seismogram.
Wadati-Benioff zone
A sloping band of seismicity defined by intermediate- and deep-focus earthquakes that occur in the downgoing slab of a convergent plate boundary
The San Andreas Fault
is a right-lateral strike-slip fault
The Himalayas, Alps, and Appalachian Mountains are all examples of convergent boundary mountains.
Numerical dating is just a comparison of age; relative dating assigns numbers.
Cenozoic, Mesozoic, Precambrian
Choose the proper listing of names to fit the following three descriptions: Age of Mammals, Age of Dinosaurs, and longest geologic time period.
Nicolaus Steno figured out how fossils can occur in rocks.
It's not possible to say just when an individual radioactive atom will decay, but it is possible to say when half of an existing quantity of radioactive material will be gone.
Carbon-14 becomes part of organisms because green plants extract it from the atmosphere for their photosynthesis, and animals consume green plants.
The age could logically be 5,300 years.
A corpse with flesh intact, found in the Alps in 1991, was dated by the carbon-14 method and showed a parent:daughter isotope ratio of approximately 1:1, with slightly more parent material than daughter material. The half-life of carbon-14 is 5,730 years. Which of the following statements is TRUE?
The inclusions are younger than the sedimentary rock they are in.
An area of slightly dipping sedimentary rock layers has large inclusions and is intruded by an igneous dike. Apply the basic principles for determining relative ages and identify the FALSE statement.
All of the possible answers are correct.
Before the development of isotopic dating methods, scientists estimated the age of the earth by:
4.57 billion-yearold meteorites are the oldest rocks found in our solar system, leading geologists to conclude this is the approximate age of the Earth.
C and E
On the diagram shown, several surfaces between rock layers are identified by letters. Choose the answer below that correctly identifies the unconformities.
Time zones are set in relation to the time at the astronomical observatory in Greenwich, England.; Standard time and time zones were established in 1883;The second is defined in terms of energy changes within the cesium atom.;Denver (105°W longitude, 40°N latitude) is seven time zones away from Greenwich, England (0° longitude, 51°N latitude).
Eighteenth- and nineteenth-century scientists tried to determine Earth's age by analyzing the thickness of sediments, the rates of geologic processes, and Earth's temperature, but crucial flaws in these techniques gave incorrect ages.
22,920 years
Charcoal (burned wood) that was used to make prehistoric drawings on cave walls in France was scraped off and analyzed. The results were 4 mg carbon-14 (parent isotope) and 60 mg nitrogen (daughter isotope). The half-life of carbon-14 is 5,730 years. How old are the cave drawings?
Scientists can date any radioactive material back only three half-lives; after this there's not enough parent material left to measure.
Carbon-14 dating is used to date anything that was once alive and has not been petrified.
Isotopic dating can be used only in a closed system, where neither parent nor daughter material has escaped.
Isotopic dating of igneous rocks tells you when the magma or lava cooled to a solid.
The "radiometric clock" starts when a radioactive mineral cools below its closure temperature.
A disconformity is a type of unconformity in which sedimentary rocks overlie either igneous or metamorphic rocks.
a surface between parallel sedimentary beds of significantly different ages. Evidence of stream erosion or existence of a paleosol (ancient soil horizon) may help in recognizing a disconformity.
cross-cutting relations
Which of the following is NOT a method to determine numerical age?
cross cutting relations
This is a method used for relative, not numerical, dating
geologic map
In 1815 William Smith correlated strata from many locations and plotted it on paper to show the spatial distribution of rock units on Earth's surface. This document was the first modern:
An unconformity is a break in the rock record that indicates the area was under water for millions of years.
a break in the rock record indicating erosion or nondeposition; being under water would be an excellent environment for deposition
Precambrian, Paleozoic, Mesozoic, Cenozoic
Which of the following shows four time divisions listed from oldest to youngest?
If you equate all Earth history to one calendar year, all recorded human history occupies the week from Christmas to New Year's Eve
Correlation matches up rock layers across distances on the basis of similar sequences of rock layers and similar fossils in the layers.
The first half-life period of carbon-14 is 5,730 years; the second half-life period of carbon-14 is half of this, and the number of years is cut in half for each succeeding half-life period.
The half-life period of any element stays constant.
there are equal amounts of parent and daughter material present after the passage of two half-lives
Which of the following statements is FALSE? On the diagram shown:
fission track analysis
Which of the following methods of determining the age of materials is a radiometric dating technique?
The boundary surface between two stratigraphic formations is called a key bed.
The boundary surface between two stratigraphic formations is called a
The skull should be dated by the carbon-14 method, since this is the method used for organic material older than 1 million years.
A hominin (human family) skull was found in a shale layer between two fine-grained igneous rock layers. There were no baked zones on the rocks above the igneous layers. The skull had been 100% fossilized and changed to stone; there was no original skull material left. On the basis of this information and the diagram, decide which of the following statements is FALSE.
inclusions says rock containing inclusions is older than the inclusions.
The principle of _______ states that the inclusions are older than the surrounding rock
You should be able to number the events in the accompanying figure in the proper order of occurrence. If the first (oldest) event is number 1, and the last (most recent) is number 8, which occurred FIFTH in the sequence?
is illustrated by scientists' seeing pillow lava form only under water, then theorizing that pillow lava found high in the mountains today did nevertheless form under water
era, period, and epoch
The names of geologic time intervals, in order from largest to smallest,
3 half-lives
A radioactive isotope of the element potassium decays to produce argon. If the ratio of argon to potassium is found to be 7:1, how many half-lives have occurred?
A black, organic rock consisting of greater than 50% carbon; it forms from the buried and altered remains of plant material.
fossil fuels
An energy resource such as oil or coal that comes from organisms that lived long ago and thus stores solar energy that reached the Earth then
greenhouse effect
The trapping of heat in the Earth's atmo sphere by carbon dioxide and other greenhouse gases, which ab sorb infrared radiation; somewhat analogous to the effect of glass in a greenhouse
The process of injecting high-pressure water and other chemicals into a drill hole to generate cracks in surrounding rock.
The waxy molecules into which the organic material in shale transforms on reaching about 100°C. At higher temperatures, kerogen transforms into oil.
oil shale
Shale containing kerogen.
reservoir rock
Rock with high porosity and permeability, so it can contain an abundant amount of easily accessible oil.
source rock
A rock (organic-rich shale) containing the raw materials from which hydrocarbons eventually form.
this is a normal fault.
From the rock layers that are drawn in the diagram, it is logical to say
Large oil fields contain such great quantities of oil because they've developed from the largest dinosaurs.
Tunnel collapse and methane gas explosion are still dangers of underground coal mining; fortunately black lung disease has been eliminated by use of a vaccine.
Drag lines are used in strip mining operations both to remove overlying soil and rock from the coal seams and to replace topsoil after the mining is done.
Lignite is described as a low-rank coal, bituminous coal is mid-rank, anthracite is high rank, and peat isn't ranked at all.
A barrel of oil is forty-two gallons of oil.
A typical reservoir rock, into which oil has migrated and collected, is
distillation column.
A vertical pipe within which heat separates the components of crude oil is called a(n):
seismic-reflection profile
is created by interpreting reflected seismic waves.
Nuclear reactors are basically steam engines; fission produces heat which changes circulating water to steam, which turns turbines that generate electricity.
Fission breaks bonds that hold protons and neutrons together in the nucleus, splits atoms into smaller pieces, and changes matter into energy
The search for an energy source to replace oil is complicated by the public's fear of nuclear energy and its insistence that the new source be economical, environmentally friendly, and clean.
At the anticlinal crest in the diagram, it would be normal to have gas sitting on top of oil sitting on top of water.
oil window
is the relatively narrow range of temperatures in which oil can form, 90-160°C.
tiny algae and plankton decomposed under conditions of heat, pressure, and low oxygen to for this
natural gas
burns more cleanly than oil does.
secondary recovery techniques usually enable drillers to get 90% of the oil out of the ground.
The United States is the largest oil consumer (roughly 25% of world consumption) but has only about 4% of the world's total reserves.
nuclear fission in the Sun that reaches Earth via the solar wind.
A typical source rock of oil, which started out as mud in which dead organic matter settled, is:
Oil has been used at some time in history as a waterproof sealant, a preservative to embalm mummies, an ingredient in patent medicines of the 1800s, and lamp oil.
Macroscopic organic material (leaves, stems, trunks) of swampy areas undergoes heat and pressure in an oxygen-poor environment over a geologically long time. The result is
Drilling mud
is a slurry of water and clay.;is pumped down the center of an oil-drilling pipe. is used to cool the drill bit and to flush rock cuttings up and out of the drill hole. weighs down oil in the drill hole and thus helps prevent gushers.
oil shale wasn't discovered until the 1980s, when the price of oil was very high.
what is a typical oil trap
Green plants produce food through photosynthesis, which is the combination of oxygen and chlorophyll to yield carbon dioxide and water.
The Oil Age we live in has a limited future because known reserves are diminishing fast and current consumption exceeds the rate of discovery of new oil by a factor of 3.
seal rock
is a necessary ingredient of an oil trap
United States
imports more than half of the oil it uses.
oil well B would yield the most oil because it's on an anticline crest in permeable reservoir rock.
On the diagram:
Once oil forms and migrates into reservoir rock in an oil trap, it can remain there forever.
Oil eventually decomposes by bacterial action or leaks through seal rock. Ancient oil fields have vanished over time; current ones, if left alone, will disappear.
Coal is considered a renewable resource because it's currently forming in swamps.
"Renewable" means on a human time scale, not a geologic one; oil and coal are both forming in today's world, but too slowly to replace themselves as we use them up.
Escaped oil on the surface is called an oil
oil and gas in an anticline trap collect at the crest of the anticline.
oil and gas in a fault trap collect at the top of tilted reservoir rock strata where they butt against the impenetrable fault surface.
in a stratigraphic trap collect where the reservoir rock layer pinches out.
in a salt dome trap collect in tilted reservoir rock strata along the flanks of the dome.
The largest oil reserves in the world are in countries around the Persian Gulf.
by Edwin Drake in 1859 in Titusville, Pennsylvania.
The first oil well was drilled:
Experts believe it is highly probable that humans will have exhausted all usable quantities of oil by the year 2150.
propane (3-carbon chain) and kerosene lubricating oil (26-carbon chain)
Which of the pairs below shows a highly volatile petroleum product as the first item and a very viscous petroleum product as the second item?
peat -> lignite -> bituminous coal -> anthracite
Coal develops in the following order:
Coal bed methane will need to be extracted by
The removal of ice at the toe of a glacier by melting, sublimation (the evaporation of ice into water vapor), and/or calving.
The reflectivity of a surface.
continental glacier
A vast sheet of ice that spreads over thousands of square km of continental crust.
ice sheet
A vast glacier that covers the landscape.
A period of time between two glaciations.
Pleistocene Ice Age
The period of time from about 2 Ma to 14,000 years ago, during which the Earth experienced an ice age.
sea ice
Ice formed by the freezing of the surface of the sea.
The evaporation of ice directly into vapor without first forming a liquid.
zone of ablation
The area of a glacier in which ablation (melting, sublimation, calving) subtracts from the glacier.
zone of accumulation
(1) The layer of regolith in which new minerals precipitate out of water passing through, thus leaving behind a load of fine clay; (2) the area of a glacier in which snowfall adds to the glacier.
Continental glaciers that enter the sea incorporate salt molecules into their crystal structure and thus become sea ice.
ice shelf
Which of the following is not a type of mountain (alpine) glacier?
Glaciers are analogous to metamorphic rocks because both involve the recrystallization of preexisting material in the solid state.
Scientists find large numbers of meteorites on Antarctic ice because the meteorites, like ice crystals of the glacier, follow a curved trajectory within the glacier; they go downward in the zone of accumulation, then upward in the zone of ablation where they collect against rocky ridges in the Transantarctic Mountains.
there were many more episodes of Pleistocene glacial advances and retreats than previously thought.
Studies of assemblages of microscopic marine plankton and their oxygen isotope ratios suggest:
A high concentration of carbon dioxide in the atmosphere
Which is not a contributing factor to the onset of major ice ages?
predicted climate cycles that have since been confirmed and named in his honor; stated there are changes in the amount and distribution of insolation received on Earth; stated there are cyclical changes in Earth's orbit and axial tilt; offered ideas that explain the timing of ice age events but not the severity of temperature change associated with ice ages.
the concentration of atmospheric carbon dioxide
The amounts of plankton and other microscopic shelled marine organisms affect:
is transparent if pure but milky white if cracked or contains air bubbles.
If all of today's ice sheets melted, the global sea level would rise only about 20 ft and seawalls could protect any coastal cities threatened.
If all of today's ice sheets melted, the global sea level would rise only about 70 ft and seawalls could protect any coastal cities threatened.
Glaciers originate on land; therefore there are no glaciers at the North Pole
During the Pleistocene the average temperature decrease was no more than 7°C along the coast and 13°C inland.
Sediment deposited in glacial environments is collectively called glacial drift.
Sediment deposited in glacial environments includes a mix of fine grained sediment and sand called erratic till.
Narrow, steep-sided, deep inlets of seawater in glacial valleys are called fjords.
lag deposits
Which term has nothing to do with glaciers?
Regions covered by glacial ice are termed periglacial environments.
The melting of ice sheets at the end of the Pleistocene caused glacial rebound in northern Canada.
The Antarctic ice sheet has been calving off huge icebergs over the last few decades.
A medial moraine forms when two glaciers join and their lateral moraines merge.
Glaciers can move by basal sliding on water underneath them.
Glacial movement is parallel to the direction of striations, not perpendicular.
Glacial striations running northeast-southwest indicate the glacier that produced them was moving from northwest to southeast.
On average, polar glaciers move faster than temperate glaciers and continental glaciers move faster than mountain glaciers.
Temperate glaciers, which usually are wet-bottomed, move faster than dry-bottomed polar glaciers, and mountain glaciers move faster than continental glaciers.
a heavy snowfall in winter coupled with relatively cool summers
Which of the following climate conditions would most likely allow glaciers to form?
Scientists can determine the direction of movement of continental glaciers by looking at glacial:
Studies show a long term cooling and the appearance of ice sheets two to three million years ago
Studies of long-term climate changes show a gradual warming of Earth since mid-Cretaceous times, ending abruptly with the appearance of ice sheets in the Arctic one Ma.
Which is not a feature resulting from glacial erosion?
Glaciers can grow smaller by melting, sublimation, or calving.
offer evidence of three or possibly four ice ages on Earth before the Pleistocene Ice Age. contain clasts that have been glacially polished and striated. consist of large clasts in a matrix of sandstone and mudstone are rocks composed of poorly sorted sediment.
Roughly half of a floating block of ice lies below the surface of the water.
A full 80% of an iceberg
New York City
was covered by the Laurentide ice sheet of the Pleistocene
Fast-moving portions of glaciers are called ice streams; episodes of fast movement of entire glaciers are called surges.
Ice melts under pressure, refreezes when pressure subsides, and thus can pluck rock fragments from the land it passes over.
Terminal, recessional, medial, and lateral are all varieties of moraines.
When the rate of ablation equals the rate of accumulation, the glacier retreats.
When the rates are equal, the toe remains fixed. When the rate of ablation exceeds the rate of accumulation, the glacier retreats.
Tarn is rocky material that has been carried along and deposited by the ice of a glacier.
tarn is a lake in a cirque.
rocky material that has been carried along and deposited by the ice of a glacier.
Kettle holes form when blocks of ice calve off the toe of a glacier, become buried in till, and then melt.
Radiometric dating of glacial deposits and fossils has made the traditional chronology of four glaciations in the United States (Wisconsinan, Illinoian, Kansan, and Nebraskan) obsolete.
Most of Earth's freshwater exists as groundwater, and the next greatest quantity is stored in glacial ice.
most of Earth's freshwater is stored as glacial ice.
Pleistocene Ice Age Changed rainfall patterns caused pluvial lakes to develop in the west and rain forests to shrink in the tropics
Pleistocene Ice Age mammoths, mastodons, woolly rhinos, saber-toothed cats, and giant cave bears inhabited North America.
pleistocene ice age windier conditions existed and created a dusty atmosphere.
pleistocene ice age early human-like species and eventually Homo sapiens existed and endured the harsh conditions.
pleistocene ice age the southern boundary of the North American tundra moved 20 latitude degrees southward.
variations in the shape of the Earth's orbit
According to Milankovitch, which of the following is a contributing factor to ice-age cycles?
Which type of moraine can a glacier have only one of?
Modern streams flowing in oversized valleys are signs of past glaciation.
The channeled scablands of eastern Washington were created by floodwaters from a huge glacially dammed lake.
When a tributary glacier melts it leaves a hanging valley above the main glacial valley.
Continental glaciers create spectacular scenery filled with horns, arêtes, cirques, and truncated spurs.
Antarctica and Greenland.
Continental ice sheets today are found only in
feedback mechanism
A condition that arises when the consequence of a phenomenon influences the phenomenon itself.
global climate change
Transformations or modifications in Earth's climate over time.
greenhouse gas
Atmospheric gases, such as carbon dioxide and methane, that regulate the Earth's atmospheric temperature by absorbing infrared radiation.
icehouse period
A period of time when the Earth's temperature was cooler than it is today and ice ages could occur.
mass-extinction event
A time when vast numbers of species abruptly vanish.
Dinosaurs became extinct at the end of the
Mass extinction events are times in Earth's history when large numbers of species abruptly vanished.
Mass extinction events may reflect catastrophic changes in Earth's climate.
Mass extinction may happen when a comet or asteroid impact starts a chain of events that blocks sunlight for weeks or even years.
Mass extinction happened 65 million years ago and was probably caused by an asteroid impact.
Which of the following elements is released into the atmosphere by all of these processes: volcanic outgassing, animal respiration and flatulence, burning of fossil fuels, and metamorphism of limestone?
"Steady-state condition" means that even though there may be a constant flow between reservoirs, the proportions of a chemical in different reservoirs remain fairly constant.
If the concentration of a chemical is steadily increasing in one reservoir at the expense of the concentration of that same chemical in another reservoir, it is termed a steady-state condition.
Shallow seas cannot ever again cover continental interiors because there has been enough sediment deposition to raise the average land surface high enough to prevent this.
Sea-level changes are cyclical; what's happened in the past will no doubt happen in the future, and interior land will get inundated by seawater.
The near-term future of the world depends heavily on human activities.
Plate tectonics movements will alter the global map significantly over the coming millions of years.
Five billion years from now scientists believe the Sun will begin to collapse, then swell to encompass the Earth.
Asteroid and comet collisions have happened in Earth's past; no doubt they'll happen again and have devastating effects.
Changes in the positions of continents, the amount of volcanic activity, the uplift of land surfaces, the formation of coal, oil, and organic shale, and life evolution events all contribute to short-term climate change.
Short-term climate changes are influenced by fluctuations in solar radiation and cosmic rays and by changes in Earth's orbit and tilt, volcanic emissions, ocean currents, surface albedo, and concentration of greenhouse gases.
Earth's atmosphere
is being polluted by rain that falls through sulfur-containing aerosols from power plants.
A worthwhile goal for society is the attainment of sustainable growth.
Methane, carbon dioxide, and several trace gases (including water) are all greenhouse gases that cause the atmosphere to cool by reflecting large amounts of solar energy back into space.
Methane, carbon dioxide, and several trace gases (including water) are all greenhouse gases that warm the atmosphere because they trap infrared radiation (heat) close to Earth's surface.
If significant global warming happens, the consequences would be a shift in climate belts, with temperate climates moving to lower latitudes.
If significant global warming happens, the consequences would be stronger storms and increased flooding
If significant global warming happens, the consequences would be a rise in sea level die to letting ice
if significant global warming happens, the consequences would be an increase in the frequency of wildfires because vegetation would be so dry.
If significant global warming happens, the consequences would be an interruption of ocean currents and the heat transfer they accomplish.
The greenhouse effect originates from human burning of fossil fuels.
The natural greenhouse effect maintains suitable life-supporting surface temperatures on Earth. Human combustion of fossil fuels causes an enhanced greenhouse effect, beyond the natural level
Earth began to differentiate into a layered planet within 100 million years of its birth.
The Moon formed from fragments of Earth and a Mars-sized planetesimal that collided with the newborn Earth.
depletion happens in high-latitude regions, particularly the Antarctic.
The Intergovernmental Panel on Climate Change (IPCC), in its 2007 report, states, unarguably, that Earth's climate system is warming, and it states with very high confidence that human activities have contributed significantly to the warming.
Air bubbles in ancient ice show the carbon-dioxide concentration of past atmospheres, and this is an indicator of atmospheric temperature.
Bubbles of air trapped in old ice show the nitrogen concentration of the ancient atmosphere, and this is an indicator of its temperature.
The oxygen-isotope ratios of ancient glacial ice indicate the atmospheric temperature of the snowfall that created the ice.
The sunspot cycle is a cyclical rise and fall of the number of magnetic storms on the Sun and is associated with increased and decreased solar radiation received by Earth.
Ice-house periods are long periods of time when Earth's atmosphere was significantly cooler than it is now.
Ice ages were times during ice-house periods when Earth was cold enough to allow ice sheets to cover much land surface.
hydrologic cycle
is a biogeochemical cycle, involving both physical and biological phenomena.
Anthropogenic (human induced) changes in the Earth systemare decreasing as technology leads to more environmentally friendly practices.
Anthropogenic (human induced) changes in the Earth system include landscape modifications resulting from construction, mining, and farming.
Anthropogenic (human induced) changes in the Earth system include the pollution of air and water
Anthropogenic (human induced) changes in the Earth system include global warming, which is greatly enhanced by society's production of greenhouse gases.
Anthropogenic (human induced) changes in the Earth system have affected the ecosystems of regions by deforestation, overgrazing, agriculture, and urbanization.
Large volcanic eruptions can put enough aerosols into the atmosphere to cause global warming, as illustrated by the summer of 1816, which was the hottest summer on record.
The large amounts of aerosols volcanoes put into the air lower atmospheric temperature, as illustrated by 1816, which is known as the year without a summer.
Subduction events and mantle plumes created solid blocks of high-density rock (basalt) that collided and coalesced to form Earth's first crust.
Subduction events and mantle plumes created solid blocks of low density granite that collided and coalesced to form Earth's first crust.
Many changes Earth undergoes don't happen to other planets because Earth is the only planet with a mobile asthenosphere and a surface temperature that straddles the freezing temperature of water.
The concentration of carbon dioxide and other greenhouse gases strongly influences Earth's temperature.
The two major factors determining Earth's temperature are the Earth-Sun distance and the concentration of oxygen in the atmosphere.
Liquid water serves as a reservoir to hold carbon dioxide that's been removed from the atmosphere.
Natural processes on Earth cause carbon dioxide to cycle through limestone, coal, several chemical-weathering reactions, and the atmosphere.
Too much carbon dioxide in Earth's atmosphere could make us as hot as Venus; greater Earth-Sun distance might make us as cold and lifeless as Mars.
Human population
has become a significant agent of global change;is currently a little over six billion;is doubling every forty-four years;reached one billion in 1850.
Ice ages are an example of global steady-state changes in the biogeochemical hydrologic cycle.
Sea-level changes
are reflected by blankets of sediment called sedimentary sequences. have been recorded on the sedimentary cycle chart. are termed eustatic if they are worldwide changes. have been as great as 300 m during the Phanerozoic eon.
Currently, large ice shelves are breaking up, the Greenland ice sheet is melting, sea ice has decreased substantially, valley glaciers worldwide are retreating, and the area of permafrost has substantially decreased.
Studies of air bubbles and oxygen-isotope ratios in glacial ice, fossil pollen, tree rings, and the stratigraphic record are all useful in determining paleoclimates.