Geology Online Practice ch - 7 Flashcards

Terms Definitions
2 cm/yr
Based on the latest technology, the relative plate motions show North America is moving away from Europe at a rate of approximately...
plate boundaries
Most of Earth's seismic activity, volcanism, and mountain building occur along...
reverse polarity
Paleomagnetism of rocks that exhibit a pattern or orientation different than the modern-day magnetic field is labeled...
volcanic island arcs
The Aleutian, Mariana, and Tonga Islands are examples of...
the location of Pangaea
Glacial deposits covering extensive areas of the modern-day Southern Hemisphere, including India, 300 million years ago is evidence for...
true (This is an example of oceanic-continental convergence.)
T or F - In North America, the Cascade Range is part of a continental volcanic arc associated with the subduction of oceanic lithosphere.
false (Wegener's Continental Drift proposed continents moving through the ocean floor or floating like lily pads.)
T or F - The Plate Tectonic Theory proposes that the continents move through the ocean floor.
The type of plate boundary where plates move together, causing one of the slabs of lithosphere to be consumed into the mantle as it descends beneath an overriding plate, is called a ____________ boundary.
false (Drill core data helped to establish that the age of the sediment increases with increasing distance from the ridge.)
T or F - The oldest and thickest seafloor sediments are found at the ridge crest.
true (There is a lot of hazardous activity, strong earthquakes and volcanic activity, around the Pacific Ocean basin.)
T or F - The "Ring of Fire" is an area of earthquake and volcanic activity that encircles the Pacific Ocean basin.
slab pull
During subduction, when a slab sinks into the asthenosphere, the trailing plate follows along because of...
along divergent boundaries
Ridge push is most important...
true (The East African rift represents the initial stage in the breakup of a continent.)
T or F - The East African Rift Valley is an example of continental rifting.
downcutting of the Colorado River
The Grand Canyon formed directly through geological processes related to...
true (Even if the same processes are operating, this does not mean they are operating at the same rate or intensity.)
T or F - The rates of geologic processes have undoubtedly varied through time.
false (Nicholas Steno completed a lot of his important work in the mountains of western Italy.)
T or F - Nicholas Steno is best known for his trips and descriptions through the Grand Canyon.
The doctrine of ____________ was put forth by James Hutton in his monumental work Theory of the Earth.
The understanding of a relatively young Earth required explanations of sudden and worldwide disasters consistent with the philosophy of...
false (Sedimentation rates may calculate different ages worldwide and unconformities could result in inaccurate rates.)
T or F - The age of Earth is best determined using sedimentation rates.
false (Fossils are formed in many ways (including petrification) but the study of fossils is paleontology.)
T or F - The scientific study of fossils is called petrology.
Fossils that are widespread geographically and are limited to a short span of time are referred to as ____________ fossils.
true (This law of superposition can apply to any materials that settle as surface deposits including lava flows or ash deposits.)
T or F - In an undeformed sequence or package of sedimentary rocks, each bed is older than the one above it and younger than the one below.
false (As a general rule, rapid burial and hard parts increase the chances of fossilization.)
T or F - Rapid burial and the possession of soft parts are necessary conditions for fossilization.
The type of date that places events in proper sequence is referred to as a ____________ date.
The process by which atomic nuclei spontaneously break apart (decay) is termed...
A particle that consists of two protons and two neutrons is called a/an ________ particle.
2 half-lives
How many half-lives have passed if the parent:daughter ratio is 1:3?
true (The three isotopes are U-234, U-235, and U-238.)
T or F - The element uranium is known to have three isotopes.
false (Different elements may form as well as different isotopes depending on the mechanism of radioactive decay.)
T or F - Radioactive decay always results in a different isotope of the same element.
radiocarbon dating
This type of dating technique is most useful for recent geologic events and the historic past.
the geologic time scale
Geologic events of Earth's history and the past are arranged in a meaningful way as part of...
igneous rocks
Numerical radiometric dates are best obtained from materials with which of the following properties?
true ("Phanerozoic" means visible life.)
T or F - The widespread occurrence of abundant fossils that document major evolutionary trends marks the beginning of the Phanerozoic eon.
false (Earth's atmosphere has evolved and constantly changed over time.)
T or F - Earth's first primitive atmosphere was composed entirely of nitrogen.
false (The Precambrian represents 88% of geologic time.)
T or F - The largest division of geologic time is a period.
Earth's original atmosphere consisted of gases expelled from within the planet during a process known as...
true (Photosynthesis releases oxygen into the atmosphere.)
T or F - Plants are responsible for dramatically altering the composition of the entire planet's atmosphere.
false (Oceans were able to form only as Earth cooled enough for water vapor to condense to clouds and rain could accumulate on the surface.)
T or F - The current distribution of continents and oceans today resemble what Earth probably looked like 4.5 billion years ago.
The smallest divisions of the geologic time scale are referred to as...
Which block of geologic time spans the largest percentage of Earth's history?
true (Life was more diverse than just fishes, but many modern fishes can be matched back to developments during this time period, and fishes were dominant during this time.)
T or F - The Devonian period is often called the "age of fishes."
false (The development of hard parts was noticeable during the Cambrian period (Early Paleozoic).)
T or F - No life forms possessed hard parts until the late Paleozoic.
The supercontinent of Pangaea formed during the late ____________ era.
true (Over 600 genera of these mud-burrowing marine scavengers lived happily in the Paleozoic seas worldwide.)
T or F - Trilobites were abundant and flourished during the Cambrian period.
true (The rock record and the life record (fossils) allow scientists to infer information about the environments. Worldwide, the time from 354-290 million years is often referred to as the Carboniferous indicating the importance of fossil fuels (coal).)
T or F - North American coal deposits are associated with vast swamps that existed during the Pennsylvanian Period.
false (The Phanerozoic is an eon of "visible life" and includes the Paleozoic, Mesozoic, and Cenozoic eras.)
T or F - The most recent 540 million years of Earth's history are divided into four eras: Phanerozoic, Paleozoic, Mesozoic, and Cenozoic.
true (Although debated for years, there is evidence from the structure of the skeletons and the bones to indicate that at least some dinosaurs were warm-blooded.)
T or F - Evidence indicates that some dinosaurs, unlike their present-day reptile relatives, were warm-blooded.
true (K is the abbreviation used for the Cretaceous (the last period of the Mesozoic), and the T is the abbreviation used for the Tertiary (the first period of the Cenozoic).)
T or F - The Mesozoic era ends at the K-T boundary.
true (The development and adaptation of a shelled egg was a key part of the diverse reptilian success.)
T or F - Reptiles were dominant during the Mesozoic.
false (The rock record and life record are well preserved for many events during the Mesozoic.)
T or F - The Mesozoic era is the least understood span of Earth's history.
a terrestrial environment
For much of North America, Triassic period rock deposits predominantly indicate...
___________ mammals develop within the mother's body for a longer period of time and the young are relatively mature at birth.
recent time
Cenozoic means...
Flowering plants with covered seeds are called...
Age of Mammals
The Cenozoic is best known as the...
The Basin and Range province stretching from northern Nevada into Mexico formed through crustal movement and high heat flow during the __________ epoch.
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