TEST #2 Flashcards
This metamorphic rock is composed of alternating bands of light and dark silicate minerals.
Gneiss
A Metamorphic Facies is typically defined based on:
Two or more metamorphic minerals that occur together over a range of pressures and temperatures
Which of the following is the parent rock of quartzite?
Sandstone
Minerals that are good indictors of metamorphic environments are called:
Index minerals
Which low-grade metamorphic rock displays thin, parallel layers and contains very fine grains of mica?
Slate
______ is the process by which a rock changes form or mineral content as a result of environmental changes such as heat and pressure.
Metamorphism
Contact metamorphism is caused by ____, whereas regional metamorphism involves _______.
The heat of a nearby intrusion; both heat and stress
_____ is a widespread type of metamorphism typically associated with mountain building.
Regional metamorphism
Which of the following lists is in correct order going from lower to higher grade metamorphism?
Slate, phyllite, mica, schist
What is the definition of a parent rock (also known as a protolith)?
The rock that was altered by metamorphism
Which of the following is an essential characteristic of an index fossil?
The organism only lived for a short period of geologic time
Which scientist is credited with developing the law of superposition?
Nicholas Steno
The first 3 periods of the Paleozoic era are (in order from oldest to youngest) are:
Cambrian, Ordovician, and Silurian
What is the nature of the unconformity between sediments J and N as shown in the diagram?
Disconformity
About 85% of geologic time is represented by the time span called the:
Precambrian
A layer of sandstone is in contact with a mass of granite. The granite contains small pieces of the sandstone. What rock is older?
Sandstone
Radiometric dating is least useful for dating _____ rocks.
Sedimentary
You are trying to determine the age of a lava flow using an isotope with a half-life of 1.5 million years. If the sample has gone through four half-lives, what is the age of the rock?
6 million years
A neutron is a combination of a(n) ____ and a(n) _____.
electron, proton
The half-life of carbon-14 about 6000 years. Assume that a sample of charcoal formed by burning of living wood 15000 years ago. How much of the original carbon-14 would remain today?
Between one-fourth and one-eighth
How does tensional force charge a rock body?
Stretch and thin the rock
Faults form in _____ temperature- _____ pressure environments.
low; low
Which tectonic boundary is associated with compressional stress?
Convergent
Linear upfolded structures with the oldest strata in the center are termed:
Anticlines
Faults having primarily horizontal movement are called:
Strike-slip faults
Tensional forces normally cause which of the following?
Normal faults
A low angle reverse fault is termed:
Thrust fault
Anticlines and synclines are generally:
Products of compressional stress
Which of the following combinations should favor folding rather than faulting?
High temperature and high confining pressure
What is the outcrop pattern of a plunging syncline?
The layers will open up in the direction of plunge
Which of the following is used to describe what occurs to produce an earthquake?
Elastic rebound
A point on the Earth’s surface which lies vertically above the point of origin of an earthquake is termed the
Epicenter
Earthquake A is classified as a 3 on the Richter scale. Earthquake B is classified as a 6. Approximately how many times energy has Earthquake B released than Earthquake A?
33000 times
Primary waves are typically best seen (most easily recorded) on which of the following seismograph records:
Vertical
The type of seismic wave propagates through intervening material by compressing and dilating the rocks in the direction the wave is traveling.
P waves
The type of seismic waves travels the most rapidly.
P waves
The asthenosphere is a part of the:
Mantle
The dense core of the earth is thought to consist predominantly of:
Iron
What will happen to a seismic wave when it is refracted?
The wave will be bent when passing into a material of differing density
Which one of the following is the thinnest layer of the earth?
Crust
Wegner dubbed the Permian supercontinent:
Pangea
Mountains formed by the collision between continents are the:
Himalayas
The African Rift valleys are associated with a:
Divergent boundary
In the plate tectonics model, the earth’s outer shell consists of about _______ individual plates.
20
Which of the following is associated with an active continental margin?
Convergent boundaries
Charles Darwin was first time explain how reef-building organism which require shallow, sunlight water could create reef complexes that extend for thousands of meters below sea level. Darwin hypothesized that:
As volcanic islands with fringing coral reefs began to sink, these organisms kept pace by building the reef complex upward
What rock would you expect to find associated with a mid-ocean ridge?
Basalt
Island arcs are associated with:
Convergent (oceanic-oceanic) boundaries
The collision of North America and Europe/Asia during the Paleozoic era resulting in the formation of the
Appalachians
A sample of basalt in which the magnetic field is oriented horizontally probably cooled:
Near the equator
What tool is often used to measure the topography of the sea floor today?
Sonar
The formation of the Hawaiian Islands is associated with:
No plate boundary of any kind
If the earth’s magnetic field did not occasionally reverse polarity:
The sea floor would not contain (produce) magnetic stripes.
The Andes mountains were generated at a:
Convergent (oceanic-continental) boundary
What are the two types of continental margins?
Passive and active
