Geology 1500 Exam 1
Which of these statements is most consistent with the law of uniformitarianism?
"The present is the key to the past."
A typical rate of seafloor spreading in the Atlantic Ocean is ______.
2 centimeters per year
The current accepted age of Earth is ________ years.
4.6 billion years old
In the early part of the 20th century, _____ argued forcefully for continental drift
Alfred Wegener
Which example below represents relative age dating?
Angela is older than Karen.
Which of the following best describes the fundamental concept of superposition?
Any sedimentary deposit accumulates on top of older rock or sediment layers.
which one is an important fundamental assumption underlying the plate tectonic theory?
Earth's diameter has been essentially constant over time
Which of the following statements is TRUE?
Earth's magnetic field reverses over geologic time
A scientific theory is a tentative or untested explanation that is proposed to explain scientific observations.
False
According to the nebular hypothesis, all of the bodies in the universe evolved from a rotating cloud of gases and dust about 5 billion years ago.
False
As the South Atlantic basin widens by seafloor spreading, Africa and South America are moving closer together.
False
Earth's radius and surface area are slowly increasing to accommodate the new oceanic crust and being formed at mid-oceanic ridges.
False
Iceland is a good example of an island arc, formed from an oceanic-oceanic plate collision
False
Igneous rocks are produced largely by the deposition and consolidation of surface materials like sand and mud.
False
The asthenosphere is a relatively cool and rigid shell that overlies the lithosphere.
False
The currently accepted age of Earth is approximately 4.5 million years.
False
The rate of seafloor spreading is, on the average, about one meter per year.
False
______ was an important 18th-century English geologist and proponent of uniformitarianism.
James Hutton
Describe what happens during the rock cycle.
Magma (molten rock) > cooling and crystallization > Igneous ("fire-formed") rock > weathering, transportation, and deposition > sediment > compaction and cementation > sedimentary ("setting" rock) > heat and pressure > metamorphic ("changed form" rock) > melting
the _______ proposes that the bodies of our solar system formed at essentially the same time from a rotating cloud of gases and dust.
Nebular hypothesis
Linear, magnetic patterns associated with mid-ocean ridges are configured as _________.
Normal and reversed magnetized strips roughly parallel to the ridge
Deep oceanic trenches are most abundant around the rim of the ______ ocean basin.
Pacific
The _____ division of the geologic time scale is an era of the Phanerozoic eon.
Paleozoic
Former late paleozoic super continent is known as _______.
Pangaea
According to the rock cycle, any type of rock (igneous, sedimentary, or metamorphic) may be transformed into another type of rock, given enough time.
True
In general, rocks of the continental crust are less dense than rocks of the oceanic crust
True
Internally, the Earth consists of spherical shells with different compositions and densities.
True
Much of our modeling of Earth's interior comes from the study of seismic or earthquake waves.
True
Oldest rocks on the seafloor are much younger than the oldest rocks on the continents.
True
Seafloor spreading rates can be estimated if the geologic ages of the magnetic field reversals are independently known.
True
The doctrine of uniformitarianism implies that the current forces and processes shaping the Earth have been operating for a very long time.
True
The law of superposition applies primarily to sedimentary rocks and lava flows.
True
The lithosphere and asthenosphere are both layers of Earth defined by their composition.
True
The oldest of rocks of the oceanic crust are found in deep ocean trenches far away from active, mid-ocean ridges.
True
The volcanoes of Hawaii are localized above a deep mantle hot spot; they are not part of the East Pacific oceanic ridge.
True
Wegener's continental drift hypothesis was weakened because a viable mechanism for moving the continents was lacking.
True
All of the following are possible steps of a scientific investigation except for _____.
assumption of conclusions without prior experimentation or observation.
Beneath Earth's lithosphere, the hotter, weaker zone known as the _____ allows for motion of Earth's rigid outer shell.
asthenosphere
the ___________ is not a part of the Earth's physical environment.
astrosphere
The ______ refers to the sum total of all life on Earth.
biosphere
___________, a popular natural philosophy of the 17th and 18th centuries was based on a firm belief in a very short geologic history for Earth.
catastrophism
All of the following are evidence supporting the theory of plate tectonics except for ______.
changes in the moon's orbit due to shifting plates Correct answers: hot spots, measurements of plate motions and ocean floor drilling
All of the following provide evidence or clues to the composition of Earth's interior except for ________.
comets
Australia is composed of relatively old and thick _______ ______.
continental crust
The volcanoes and deep valleys of east Africa are related to a _______.
continental rift along which parts of the African continent are beginning to slowly separate
The Aleutian Islands occur at a ________.
convergent boundary on a volcanic arc above a northward-subducting Pacific plate
Juan de Fuca plate is interacting with the North American plate where inland volcanoes and deep focus earthquakes are occurring, What type of plate boundary is this?
convergent plate boundary
The relatively stable interior portion of a continent is a known as a __________.
craton
The _______ is the thinnest layer of the Earth.
crust
New oceanic crust and lithosphere are formed at ____________.
divergent boundaries by submarine eruptions and intrusions of basaltic magma
Which boundary is characterized as a long, linear rise in the seafloor, with shallow earthquakes and volcanic activity found along its length?
divergent boundary
Why have no older oceanic rocks been discovered?
due to tectonic activity, rocks on the ocean floor are continually recycled.
Which of the following energy sources is thought to drive the lateral motions of Earth's lithospheric plates?
export of heat from deep in the mantle to the top of the asthenosphere
the Earthquakes that occur in southern California generally occur along a ______.
fault
which of the following processes can be observed at the margins of lithospheric plates?
faulting, earthquakes, volcanoes and mountain building
A very long lived magma source located deep in the mantle is called a ____________.
hot spot
Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from a _____ ______.
hot spot
The continental drift hypothesis was rejected primarily because Alfred Wegener could not ______.
identify a mechanism capable of moving continents.
In correct order from the center outward, Earth includes which units?
inner core, outer core, mantle, crust
The _________ is a logical evolutionary analog of the African Rift Valleys ten million years from now.
Red Sea
___________ ______ found in the Atlantic Ocean between North America and Europe is composed of dense and relatively young rock.
Seafloor crust
The ____ forms the relatively cool, brittle plates of plate tectonics.
lithosphere
the asthenosphere is actually a part of the _______ of the Earth.
mantle
The _______ is an example of an active, continent-continent collision.
northward movement of India into Eurasia
the _______ is thought to be a liquid, metallic region in the Earth's interior.
outer core
Slowing increasing distance between South America and Africa is due to __________ _______.
seafloor spreading
______ rocks always originate at the surface of the solid Earth.
sedimentary
Layered ________ _____ exposed by erosion can be seen when looking at the grand canyon in the United States.
sedimentary rock
Which statement is not correct?
sedimentary rocks may weather to igneous rocks
Which of the following most accurately describes the volcanoes of the Hawaiian Islands?
shield volcanoes fed by a long-lived hot spot below the Pacific lithospheric plate
deep ocean trenches are surgical evidence for
sinking of oceanic lithosphere into the mantle at a subduction zone
The composition of the core of Earth is thought to be _________.
solid iron-nickel alloy
The extremely deep ocean Marianas Trench is a result of ______.
subduction
Cooler, older, oceanic lithosphere sink into the mantle at ________.
subduction zones along convergent plate boundaries
Metamorphic rocks are created by _______________.
temperatures hot enough to change the rock in the solid state without melting it
Which of the following lithospheric plates is not included among the seven largest?
the Philippine plate
Which of the following is one of the remarkable realizations associated with the discovery of seafloor spreading?
the crust of the oceans is very young relative to the age of the continental crust.
Which sphere does the crust of Earth belong to?
the geosphere
Which of the following observations was included as evidence for Wegener's continental drift hypothesis?
the jigsaw-puzzle fit of the continents
Earth's lithospheric plates are composed of crust and which of the following layers?
the outermost portion of the mantle
deep-ocean trenches are formed by ________.
the subduction of lithosphere into the asthenosphere
A ______ is a well-tested and widely accepted view that best explains certain scientific observations.
theory
Compared to the age of Earth accepted as correct today, how did 17th and 18th century proponents of catastrophism envision the Earth's age?
they believed Earth to be much younger than current estimates.
During various times in the geologic past, the polarity of Earth's magnetic field has been reversed.
true
Himalayan Mountains are the tectonic product of a collision between India and Eurasia that began about 40 million years ago and still continues.
true
______ is often paraphrased as "the present is the key to the past."
uniformitarianism
________ is the process by which rocks breakdown in place to produce soils and sediments
weathering
Mount St. Helens and other Cascade volcanoes are _______.
young, active volcanoes built on a continental margin above a sinking slab of oceanic lithosphere
Which following statement applies to the asthenosphere, but not the lithosphere?
zone in the upper mantle that deforms by plastic flowage
_______ rocks form by crystallization and consolidation of molten magma.
Igneous
A transform plate boundary is characterized by
a deep vertical fault along which two plates slide past one another in opposite directions
Pull-apartm rift zones are generally associated with
a divergent plate boundary
When a researcher publishes research in a national journal, what part of the scientific method is he or she most likely involved with?
a hypothesis
The Hawaiian Islands were formed as a result of __________.
a mantle plume
Modern-day Red Sea is explained by plate tectonics theory because it is ____________.
a rift zone that may eventually open into a major ocean if Arabia and Africa continue to separate
Active mountain belts are mostly likely to be found _______.
along the margins of continents