ch 12 earth science
the asthenosphere can be described as A) a rigid solid B) a liquid C) plastic-like D) plasma-like
C) plastic-like
which of following is incorrectly matched? A) endogenic-internal processes B) exogenic-internal processes C) radioactive decay heat-endogenic energy source D) weathering-exogenic breaking and dissolving the crust
C) radioactive decay heat-endogenic energy source
depth of earthquake focus increases distance from ocean trench. T/F
True
earth was once in a molten state, during which materials became sorted based on density. T/F
True
ocean floor subducts under continents because the ocean floor is denser than continental material. T/F
True
the Moho mirrors the surface topography, i.e., high places on the surface of the earth overlies areas in which the Moho descends to greater depths, and vice versa. T/F
True
the age of the sea floor increases w increasing distance from a mid-ocean ridge. T/F
True
the hawaiian islands were formed as a result of a rising plume of magma from the mantle. T/F
True
the magnetic stripes found around mid-atlantic ridge were due to magnetic reversal. T/F
True
the decay rate is expressed as ___________, the time required for one half of the unstable atoms in a sample to decay into "daughter" isotopes
half-life
the oceanic crust thickness is about ___ km, and the average continental crust thickness is ____ km.
5; 30
the transportation and deposition of materials by media powered by solar energy is the A) tectonic cycle B) rock cycle C) hydrologic cycle D) mineral cycle
C) hydrologic cycle
the principle of buoyancy and balance, when applied to earth's crust, helps us to explain fluctuations in earth's outer crust, a property known as A) magnetism B) Moho effect C) isostatic adjustment D) orogenesis
C) isostatic adjustment
which layer of planet forms 80% of earth's total volume, and has an average density of 4.5 g/cm3. A) continental crust B) oceanic crust C) mantle D) core
C) mantle
radioactivity dating only can be used to measure relative time. T/F
False
since the core's mass is about one third of earth's entire mass, the volume of the core is also of one third of the earth's entire volume. T/F
False
the fluid outer core generates 90% of earth's magnetic field. T/F
True
which of the following is an exogenic process? a.) earthquakes b.)volcanism c.)flows of heat and materials in the mantle d.)weathering
d.)weathering
the youngest epoch in the geologic time scale is _________.
holocene
the geologic cycle is composed of three subsystems: _______, ________, __________.
hydrologic, rock, tectonic
three basic rock types are __________ (fire-formed, molen), ________(from settling out), and ___________(transformed from any other rock thru extreme heat or pressure).
igneous, sedimentary, metamorphic
there are two types of time, which are _________ and ____________
relative, absolute
the earth's dominant materials are __________ and ___________.
silica; iron
list three type of plate boundaries _______, ________, _________.
transform, convergent, divergent
several large, linear lakes are formed in east africa. this is evidence of what process? A) rifting B) subduction C) compression D) isostatic uplift
A) rifting
divergent plate boundaries are characteristics of A) sea floor spreading centers B) collision zone between plates C) transform plate boundaries D) all plate boundaries
A) sea floor spreading centers
heat energy and new materials are brought to the surface from the interior by the A) tectonic cycle B) rock cycle C) hydrologic cycle D) mineral cycle
A) tectonic cycle
which of the following are located along the mid-ocean ridge? A) volcanoes B) outcrops of granite C) old oceanic sediments D) none of the above
A) volcanoes
convergent plates boundaries are characteristics of A) sea floor spreading centers B) collision zone between plates C) lateral motion of plates D) all plate boundaries
B) collision zone between plates
Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest? A) era, eon, epoch, period B) eon, era, period, epoch C) epoch, era, eon, period D) period, eon, era, epoch
B) eon, era, period, epoch
When geologists or archaeologists dig downward into a unti of rock sediment, they are digging "back in time." This fact is based on the principle of ________. A) uniformitarianism B) superposition C) catastrophism D) volcanism
B) superposition
The density of material below the Moho is less than that above it.
False
the oceanic crust is less dense than the continental crust. T/F
False
uniformitarianism assumes that the same physical processes we see today are a key to understand the processes that have been operating thruout the geologic time. T/F
True
in 1912, german geophysicist and meteorologist, Alfred Wegener first proposed the ___________ hypothesis about the Earth's land mass migration.
continental drift
earth's magnetic field A) is variable, and it has phased to zero some nine times during the past 4 mill years B) is constant in its intensity C) remain a mystery as to its cause D) is principally generated in the inner core
A) is variable, and it has phased to zero some nine times during the past 4 mill years
which of the following gives the correct sequence of layers in the mantle, from bottom to top? A) mantle, upper mantle, asthenosphere B) asthenosphere, mantle, upper mantle C) upper mantle, asthenosphere, mantle D) mantle, asthenosphere, upper mantle
A) mantle, upper mantle, asthenosphere
which of the following gives the correct sequence of layers in the earth, from the surface to the center? A) crust, core, lower mantle, asthenosphere B) asthenosphere, lower mantle, crust, core C) crust, lower mantle, asthenosphere, core D) crust, asthenosphere, lower mantle, core
D) crust, asthenosphere, lower mantle, core
list four evidences wegener used to prove his hypothesis _____,___________, _______, _______.
coastal lines; fossils; rock types and mountain types; ancient climates
which of the following statements about earth's core is not true? A) it is composed primarily of iron B) the inner core is believed to be liquid and the outer core solid C) temperature in the core reaches several thousand degrees D) temperatures and pressures are higher in the inner core than in the outer core
B) the inner core is believed to be liquid and the outer core solid
knowledge of earth's interior is derived from A) direct sampling of the interior using deep-test wells B) work in earth's deepest caverns and caves C) indirect evidence involving the analysis of seismic waves D) historic and prehistoric records
C) indirect evidence involving the analysis of seismic waves
which of the following is an endogenic process? A) Weathering B) stream deposition C) volcanism D) glacial erosion
C) volcanism
which of the following plays a role in the shaping of Earth's surface? A) gravity B) the action of wind, water, and ice C) radioactive decay of atoms D) all of the above E) B & C only
D) all of the above
which of following is true of the asthenosphere? A) it contains pockets of increased heat B) it flows C) it carries the lithospheric plates D) all of the above are true E) none of above are true
D) all of the above are true
at which of the following locations does subduction occur? A) along collision zones between two continents B) at sea floor spreading zones C) above mantle hot spots D) along collision zones between continental and oceanic plates
D) along collision zones between continental and oceanic plates
Which of the following is not an example of an age-relationship based on absolute dating? A) the oldest rocks on earth is about 4.0 billion years old B) the oldest fossil on earth is about 3.5 billion years old C) the dinosaurs became extinct 65 million years ago D) the coconino formation in the grand canyon is older than the Kaibab formation
D) the coconino formation in the grand canyon is older than the Kaibab formation
two most abundant chemical elements in earth's crust are __________ and ________.
oxygen; silicon
wegener used _________ to name a supercontinent approx. 225 million years ago
pangaea
