Geog 1710 chapter 9-10
magnetic reversal
1.2 million years ago - normal .8 million- reversed .4 Million- normal
Core Volume
1/6 of earths volume
How old is the Earth?
4.6 billion years old
How old is the solar system?
4.6 billion years old
The oceanic crust thickness is about _______, and the average continental crust thickness is ______km.
5 30
Curie point
575 C
Minerals
A mineral is an inorganic (nonliving) natural compound having a specific chemical formula and possessing a crystalline structure
Rock
A rock is an assemblage of minerals bound together, or a mass of a single mineral, or undifferentiated material, or even solid organic material (such as coal)
the inner temperature at the Asthenosphere upper mantle lower mantle outer core
Asthenosphere-400 C upper mantle- 900 C lower mantle -900-4,000 C outer core 4,000- 5,000 C
The youngest epoch in the geologic time scale is
Holocene
three cycles (subsystems)
Hydrologic cycle: transportation and deposition of materials by media powered by solar energyRock cycle: formation of three types of rockTectonic cycle : transportation of heat energy and new materials to the surface
Alfred Wegner
In Origin of Continents and Oceans. Wegener set forth his hypothesis of continental drift in 1915
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
Isostatic adjustment
Which of the following is NOT true of the asthenosphere?
It is beneath the upper mantle.
Two most abundant chemical elements in Earth's crust are
Oxygen silicon
Wegener used ________to name a supercontinent approximately 225 million years ago.
Pangaea
Principle of Superposition
Rock and sediment always are arranged with the youngest bed "superposed"toward the top of a rock formation and the oldest at the base, if there have not been disturbed.
Which of the following is not an example of an age-relationship based on absolute dating?
The Coconino formation in the Grand Canyon is older than the Kaibab formation.
earths magnetism
The fluid outer core generates 90% of Earth's magnetic field, because it is made of liquid molten metallic iron.• Migration of the north magnetic pole (NMP): NMP in 2016 was at 86.4oN,166.3oW.• Magnetic poles and geographic poles are different!
Which of the following statements about Earth's core is not true?
The inner core is believed to be liquid and the outer core solid.
how do we know earths age?
Two facts: -The oldest rock on Earth is about 4.0 billion years old. -The oldest fossil on Earth is about 3.5 billion years old.
How do we know the history of the geomagnetic reversal?
We can see this in the magnetic patterns found in volcanic rocks, especially those recovered from the ocean floors. (googled)
radiometric dating
a method of dating geological or archeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample. (googled)
periodic table
a tabular display of the chemical elements. -look up image
how old is the moon
about the same age as Earth
There are two types of time, which are
absolute and relative
At which of the following locations does subduction occur?
along collision zones between continental and oceanic plates
Convergent plates boundaries are characteristics of
collision zones between plates
Which of the following gives the correct sequence of layers in the Earth, from the surface to the center?
crust, asthenosphere, lower mantle, core
List three types of plate boundaries: ________boundary, ________boundary, and __________ boundary.
divergent convergent transform
Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest?
eon, era, period, epoch
what are exogenic systems
external processes that set into motion air, water, and ice, all powered by solar energy
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.
false
The density of material below the Moho is less than that above it.
false
The oceanic crust is less dense than the continental crust.
false
Earth's Interior Density
gets more dense as it gets closer to the inner core
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 transportation and deposition of materials by media powered by solar energy is the
hydrologic cycle
Three basic rock types are _________(fire-formed, molten), ________(from settling out), and _________(transformed from any other rock through extreme heat or pressure).
igneous sedimentary metamorphic
Knowledge of Earth's interior is derived from
indirect evidence involving the analysis of seismic waves
what are endogenic systems
internal processes that produce flows of heat and material from deep below Earth's crust
Earth's magnetic field
remain a mystery as to its cause
Several large, linear lakes are formed in East Africa. This is evidence of what process?
rifting
Divergent plate boundaries are characteristics of
sea-floor spreading centers
The Earth's dominant materials are
silica and iron
When geologists or archaeologists dig downward into a unit of rock or sediment, they are digging "back in time". This fact is based on the principle of_________.
superposition
Heat energy and new materials are brought to the surface from the interior by the
tectonic cycle
What is radioactivity?
the emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei. (googled)
daughter isotope
the stable isotope produced by the radioactive decay of the parent isotope. it
What is a half-life?
the time taken for the radioactivity of a specified isotope to fall to half its original value(daughter isotope)
Depth of earthquake focus increases with increasing distance from ocean trench.
true
Earth was once in a molten state, during which materials became sorted based on density.
true
Ocean floor subducts under continents because the ocean floor is denser than continental material.
true
The Hawaiian Islands were formed as a result of a rising plume of magma from the mantle.
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.
true
The age of the sea floor increases with increasing distance from a mid-ocean ridge.
true
The fluid outer core generates 90% of Earth's magnetic field.
true
The magnetic stripes found around mid-Atlantic ridge were due to the magnetic reversal.
true
Uniformitarianism assumes that the same physical processes we see today are a key to understand the processes that have been operating throughout the geologic time.
true
Which of the following gives the correct sequence of layers in the mantle, from bottom to top?
upper mantle, asthenosphere, lower mantle
Which of the following is an endogenic process?
volcanism
Which of the following is an exogenic process?
weathering
Earth's mantle
•Average depth is about 2900 km. •Two parts: lower mantle and upper mantle•Consists of 80% Earth's total volume•Average density is 4.5g/cm3.•The boundary between the uppermost mantle and the crust above is called the Mohorovicicdiscontinuity, or Moho.
Wegener's Four Evidences
•Coastal lines •Fossils •Rock types and mountain belts •Ancient climates
seismic waves
•Seismic waves travel at a higher speed in the cooler and more rigid areas than in the hotter and softer areas.•The plastic zones do not transmit some seismic waves, but absorb them.•Density changes could induce reflection and refraction of seismic waves.
Principle of Uniformitarianism
•The same physical processes active in the environment today have been operating throughout the geologic time.•"The present is the key to the past."•Earthquakes, volcanic eruptions, landslides, mountain-building have been happening over the history of Earth.
Radioactivity dating only can be used to measure relative time.
False
In 1912, German geophysicist and meteorologist, Alfred Wegener first proposed the__________ hypothesis about the Earth's land mass migration.
Continental Drift
Formation of Earth
Earth is thought to have condensed and congealed from a nebula of dust, gas, and icy comets about 4.6 billion years ago.
the two energy sources
Earth's internal heat (radioactive decay) and solar energy (external)
Isostatic
iso = "equal," static = "standstill" The state of gravitational equilibrium between the lithosphere and asthenosphere such that the tectonic plates "float" at an elevation that depends on their thickness and density.
boyancy
less dense than wood
Which layer of planet forms 80% of Earth's total volume, and has an average density of 4.5 g/cm3.
mantle
What is the Holocene?
olocene•Holocene is the youngest epoch in the geologic time scale
The asthenosphere can be described as
plastic-like
Which of the following is incorrectly matched?
radioactive decay heat-exogenic energy source
