The Dynamic Planet Flashcards
1
Q
What are the two Broad Earth Systems?
A
Endogenic and Exogenic
2
Q
What is an Endogenic System?
A
Endogenic system encompasses internal processes that produce flows of heat and material from deep below Earth’s crust (Tectonics, Earthquakes, and Volcanism).
3
Q
What is an Exogenic system?
A
Exogenic system involves external processes that set into motion air, water, and ice (Rivers, Landforms, Weathering, Erosion, Oceans, Glaciers).
4
Q
What is the geologic time scale?
A
Eon>Era>Period>Epoch
5
Q
What is the principal of Superposition?
A
Rock and sediment are always arranged with the youngest bed ‘superposed’ toward the top of a rock formation and the oldest at the base. If they have not been disturbed.
6
Q
How old is the solar system?
A
The sun and its solar system are estimated to have formed more than 4.6 billion years ago.
7
Q
How old is our Earth?
A
‘Present thinking’ places Earths age at 4.5-4.6 billion years ago.
8
Q
Define Holocene:
A
the youngest epoch in geologic time, characteristics of postglacial conditions since the retreat of the continental glaciers, about 11,500 years ago.
9
Q
When was the last ice age?
A
the last ice age occurred just prior to 11,500 years ago, during the Pleistocene
10
Q
How do we know the age of the Earth? (2)
A
-The oldest rock on Earth is about 4.0 billion years old. The oldest fossil on Earth is about 3.5 billion years old. Maybe earlier?
-Radiometric Dating: Half-life, the decay-rate, is the time required for one-half of the unstable (radioactive) atoms in a rock or fossil sample to decay into “daughter” isotopes.
11
Q
What is the Principle of Uniformitarianism?
A
The same physical processes active in the environment today have been operating throughout geologic time.
12
Q
When was the formation of the Earth?
A
Earth is thought to have condensed and congealed from a nebula of dust, gas, and icy comets about 4.5 – 4.6 billion years ago.
13
Q
What were the two dominant materials in the formation of earth?
A
Silicon and iron
14
Q
True or False: During the early stages of the formation, Earth’s temperature was so high that silica and iron were all in liquid state.
A
True
15
Q
What are Seismic Waves?
A
Seismic waves travel at a higher speed in the cooler and more rigid areas than in the hotter and softer areas.
16
Q
How are Seismic Waves used by scientists?
A
Scientists use seismic waves to probe Earth’s internal structure and density profile. An earthquake or underground nuclear test sends shock waves through the planet.
17
Q
What could changes in density do in terms of Seismic Waves?
A
Density changes could induce reflection and refraction of seismic waves
18
Q
Why is the inner core of the earth solid?
A
Pressure. Relationships between pressure and temperature
19
Q
What is Earths core made of?
A
Inner core + Outer Core
20
Q
True or False: earths outer core is solid.
A
False, it is liquid.
21
Q
How much of the earths mass is the Core Mass?
A
1/3
22
Q
What is Earths Magnetism?
A
The fluid outer core is mainly responsible for generating Earth’s magnetic field, because it is made of circulating liquid molten metallic iron.
23
Q
In which direction is earths magnetism rapidly drifting?
A
Northward and westward/
24
Q
Are magnetic and geographic poles different?
A
Yes.
25
What is earths mantle?
Average depth is about 2900 km. Consists of 80% Earth’s total volume. Average density is 4.5g/cm3
26
What are the two parts of earths mantle?
Lower mantle and upper mantle
27
What is boundary between the uppermost mantle and the crust above it?
Mohorovicic discontinuity (seismic waves increase rapidly at this zone).
28
What is the Asthenosphere?
Between the upper mantle and the uppermost mantle, there is a plastic-like layer called the asthenosphere.
29
When will the plastic layer (AKA asthenosphere) flow?
When force is present.
30
What does the lithosphere consist of?
Lithosphere consists of the crust and the uppermost mantle
31
What does Buoyancy tell us?
Buoyancy tells us that something less dense (e.g., wood, ice) floats in something denser (e.g., water).
32
Where does Earths Lithosphere float?
Earth’s lithosphere (crust and uppermost mantle) floats on the denser layers beneath, much like a boat floating on water.
33
Where does the lithosphere sink?
Where the load is greater (e.g., under glaciers, or mountains), the lithosphere tends to sink, or ride lower in the asthenosphere.
34
What is recovery uplift known as?
Isostatic Rebound
35
What does Isostatic Rebound mean?
The lithosphere is in a constant state of compensating adjustment, or isostasy. (the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression).
36
Explain Isostatic adjustment:
Isostatic (iso = “equal,” static = “standstill”) refers to 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.
37
What is the continental drift and who presented it?
In 1912, German geophysicist Alfred Wegener presented an idea that challenged long held assumptions in geology, and three years later published his book Origin of the Continents and Oceans.
38
What is the evidence of plate tectonics?
-Jig-saw puzzle like match-up of continents.
-Correlation of rock types and structure across continents.
-Occurrence of the mid-oceanic ridge.
-Distribution and types of volcanism, earthquakes, and mountain building
-Age of ocean basin (along mid-ocean ridges)
-The fossil record / biogeography
39
What is the theory of Plate Tectonics?
Plate Tectonics is the theory that the lithosphere (remember crust + uppermost mantle) is divided into several plates that float independently over the mantle (more specifically, the asthenosphere).
40
In short, what does Plate Tectonics theory explain?
Plate Tectonics theory describes the motion of Earth’s lithosphere.
41
What are the two types of Earth Crusts?
Oceanic Crust and Continental Crust
42
What is the Oceanic Crust?
Oceanic crust, which accounts for about 0.1% of Earth’s mass, can be up to 10 km thick under the oceans but is absent beneath the continents.
43
What is the Continental Crust?
Continental crust accounts for about 0.4% of Earth’s mass and is present only in continental areas where it is generally 30 to 40 km in thickness.
-Less dense (approx. 2.7g / cm3)
44
What are the types of Plate Boundaries (3)?
-Convergent Boundary
-Divergent Boundary
-Transfrom Boundary
45
What is the Convergent Boundary?
Convergent boundaries occur in areas of crustal collision and subduction, where areas of continental and oceanic lithosphere meet, crust is compressed and then lost in a destructional process as it moves downward into the mantle.
-Convergent boundaries form subduction zones, such as off the west coast of South and Central America, along the Aleutian Island trenches, and along the east coast of Japan.
-Convergent boundaries also occur where two plates of continental crust collide, such as the collision zone between India and Asia, and where oceanic plates collide, such as along the deep trenches in the western Pacific Ocean.
46
What is the Divergent Boundary?
Divergent boundaries occur in areas of seafloor spreading, where upwelling material from the mantle forms new seafloor and lithospheric plates spread apart in a constructional process. An example is the divergent boundary along the East Pacific Rise, which gives birth to the Nazca plate (moving eastward) and the Pacific plate (moving northwestward).
47
What is the Transform Boundary?
Transform boundaries occur where plates slide past one another, usually at right angles, to a seafloor spreading center. These are the fractures stretching across the mid-ocean ridge system worldwide.
48
What is the Juan de Fuca Plate?
Tiny plate located between the North American and Pacific plates (off the coast of BC).
49
What is the Juan de Fuca Plate associated with?
Cascadia subduction zone, associated with volcanic activity (mount St. Helens) and megathrust earthquakes.
50
What happens when plates move last each other horizontally?
As plates move past each other horizontally, they form a type of fault, or fracture, in Earth’s crust, called a transform fault.
51
What is a Transform Fault?
As plates move past each other horizontally, they form a type of fault, or fracture, in Earth’s crust.
52
What are ways to test plate tectonics model?
Seafloor spreading, Age of the seafloor, and Earthquake and volcanic activity.
53
What are Hot Spots?
Volcanic activity is often associated with plate boundaries (above areas of subduction)
54
How are Hawaiian Islands formed?
The Hawaiian Islands were /are being formed by a plume of upwelling magma in the middle of the Pacific plate.
55
What is the youngest island?
The newest (or youngest) island is the big island of Hawai’i, approximately 400,000 years old (still expanding).
56
Is Mauan Kea dormant or active?
Dormant, 4205m above sea level.
57
What are some active volcanoes?
Mauna Loa and Kilauea
58
How old are the oldest seamounts?
~80 million
59
Where are the oldest seamounts?
Approaching the Aleutian trench, where they will be subducted under the NA plate.
60
Define a Mineral:
A mineral is an inorganic (nonliving) natural compound having a specific chemical formula and possessing a crystalline structure.
61
Is ice considered a mineral?
Yes, by definition
62
Define a 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).
63
What are the Three basic rock types?
-Igneous (fire-formed, molten, solidified from melted rock)
-Sedimentary (from settling out)
- Metamorphic (altered, changes form)
64
What are the two most common elements in the earths crust?
Oxygen and Silicon
65
What is the main power source for the underground part of the rock cycle?
radiogenic heat
66
How is radiogenic heat released?
slowly released by the radioactive decay of unstable isotopes
67
What is the exogenic source vs. an endogenic source?
Exogenic: powered from external sources, the hydrological cycle.
Endogenic process: within earth's core.
68
True or False: water plays a huge role in weathering and erosion.
True.
69
What process allows the earths radioactive heat to decay?
sea floor spreading center from diverging plates allows heat from earth's radioactive to decay.
70
What is a secondary power source for the rock cycle?
A secondary power source for the rock cycle is gravity (the pressure on the underlying strata rises steadily at a rate of about 1,000 atmospheres every 30 km).
71
What is the above-ground portion of the cycle of rock transformation dependent on?
It is dependent on the movement of air, water, and glacial ice to transport rock particles or sediment (processes driven by solar energy).
72
Explain the rock cycle:
Igneous rock can be weathered due to exogenic processes through weathering, erosion, transported in the form of sediment through processes like lithification (the formation of rock). Sediment gets squished and pressurized together, forming new sedimentary rock, the sedimentary rock can then undergo transformation. In the presence of heat, it is going to change that sedimentary rock into something new, a new metamorphic rock. This metamorphic rock might get subducted where it can melt. If it melts, it becomes molten rock. Magma, which once cooled and solidified, becomes the new igneous rock.
73
True or False: metamorphic rock and/or sedimentary rock can also undergo weathering and erosion.
True
74
True or False: sedimentary rock or igneous rock can also melt and turn into molten rock, which cools and forms new igneous rock.
true
75
What are the three basic rock types?
Igneous
Sedimentary
Metamorphic
76
Explain what an Igneous rock is:
Igneous rock crystallizes from hot, molten magma that originates deep below the surface of the Earth.
77
Define a Sedimentary rock:
(from settling out)
-Clastic (bits of rock, from weathering), chemical, biological. Depends on where it comes from.
78
Define a Metamorphic Rock:
(altered)
- A change in structure (of igneous or sedimentary rock) due to some combination of extreme heat, pressure, and/ or chemicals.
79
What are the two layers in which Igneous rock can solidify?
Intrusive vs. Extrusive
80
What is Intrusive Igneous rock?
Molten rock Solidifies within (in)
81
What is Igneous extrusive rock?
Molten rock Solidifies on top of earths crust (EXtrusive, lava)
82
True or False: different minerals solidify or crystallize at different temperatures
True
83
What are the two main categories for classifying Igneous rocks?
Felsic and Mafic
84
What do Felsic and Mafic categorization consider?
The types, shapes, color, size, etc. of minerals within
85
Define Felsic Minerals:
Felsic minerals are light in color (white, pink, or greyish) and lower in density than the other silicate minerals; they form at comparatively low temperatures.
86
Define Mafic Minerals:
Mafic minerals are typically dark in color (usually black) and are denser than the felsic minerals. Reminder: Mafic minerals are characteristically found in rocks that solidify at high temperatures.
87
Which mineral in Igneous rocks solidify at a lower temperature?
Felsic
88
True or False: Granite is one of the most common intrusive igneous rock
True
89
What type of rock is granite classified as?
Because most of the volume of granite is of felsic minerals, granite is classified as a felsic igneous rock. You can see the little grains (minerals) that make up the rock.
90
What is an Extrusive Igneous rock?
Extrusive igneous rock, which cools rapidly, is fine-textured, with individual crystals that can only be seen through a microscope. Most lava solidifies as a dense, uniform rock with a dark, dull surface.
91
In what type of Igneous rock does Obsidian form, and how?
Extrusive Igneous rock.
Sometimes lava cools to form shiny obsidian (volcanic glass, just an example of an extrusive igneous rock).
92
What is Scoria, and what type of rock does it form in?
If the lava contains dissolved gases, it may solidify to form scoria, a rock with a frothy, bubble-filled texture. In general, Water can more easily penetrate extrusive igneous rocks, which makes them more susceptible to weathering than intrusive igneous rocks.
93
Define a Sedimentary rock:
Sedimentary rocks are formed from mineral particles derived from pre-existing rock of any of the three rock classes — igneous, metamorphic, or sedimentary.
94
What is the most common exposed rock type?
Sedimentary
95
True or False: Sedimentary rocks make up a large percent of earths mass.
False; they account for only about 5 percent of the total mass of the Earth’s rocks because they are only found within a comparatively thin layer over igneous and metamorphic rocks.
96
What is the process of sediment?
Deposition, Chemical precipitation, Or from the compaction of organic materials. Solid rock is eroded and fragmented, yielding particles of many sizes and mineral compositions. When transported by a fluid medium, such as water or air, these particles are known collectively as sediment.
97
What are the three major types of sedimentary materials?
Class Sediment
Chemically Precipitated Sediment
Organic Sediment
98
______________: consists of inorganic rock and mineral fragments called clasts, bits of rock. Varying sizes
Clastic Sediment
99
__________________: consists of inorganic mineral compounds precipitated from a chemical solution.
Chemically Precipitated Sediment
100
__________________: consists of the tissues of plants and animals, accumulated and preserved after death.
Organic Sediemnt
101
How are sizes and types of sedimentary rock determined?
By Grain Size
102
True or False: Unlike igneous and metamorphic rocks, sedimentary rocks often contain fossils, making them invaluable for interpreting geologic history.
True
103
Why is Sedimentary the only type of rock with fossils within?
Metamorphic rock undergo existing rock like sedimentary and igneous undergo change due to extreme heat and pressure, which again destroys fossils.
104
__________: Sedimentary minerals and rocks deposited from concentrated solutions
Evaporites
105
What are some examples of evaporites?
Potash, Limestone and Gypsum
106
What are chemically precipitated sedimentary rocks?
Under favorable conditions, mineral compounds are deposited by evaporation from saline waters of the oceans or from lakes
107
Why are hydrocarbon compounds important to sedimentary deposits?
At various times in the geologic past, plant remains accumulated on a large scale (e.g. the carboniferous), accompanied by sinking of the area and burial of the compacted organic matter under thick layers of inorganic clastic sediments.
108
What is the end result of the Organic Sedimentary Rock?
Coal
109
Define Fossil Fuels:
The heat and pressure from the subsequent accumulation of sedimentary rock layers resulted in the reorganization of the residual carbon and hydrogen to form the hydrocarbons (fossil fuels), which were subsequently absorbed into the porous rocks (reservoirs).
110
True or False: Oil deposits and natural gas are also of organic origin and are classified as mineral fuels (not minerals)
True
111
What rock layer cap oils and gases?
Impervious Rock Layer
112
Define Metamorphic Rocks:
Metamorphic rocks are formed from igneous or sedimentary rocks that have been physically or chemically changed, usually by the subsequent application of heat and pressure during episodes of significant crustal movement.
113
What are metamorphic rocks associated with?
Plate Tectonics
114
What do crystals do in response to new external conditions? and what is the result?
Minerals (crystals) change size, shape, and/or composition in response to new external conditions. This results in a new (metamorphic) rock that has an altered appearance, sometimes strikingly different from what it used to look like before metamorphism.
115
What is the parent rock?
The parent rock is the igneous or sedimentary rock from which the new metamorphic rock was derived
116
What are the two main categories of Metamorphic rock?
Foliated and Non-Folaited
117
___________: a visible pattern type that occurs when the minerals in the rock are banded or layered.
Foliated
118
_________________: : This provides a means of classifying metamorphic rock, simply based on the presence or absence of foliation
Non-Foliated
119
When do we get metamorphic rock?
from the movement of tectonic plates; if we have an oceanic plate meeting a continental plate, this oceanic plate is being subducted. There is a ton of pressure involved in the pushing together of these plates in subduction.
120
What are the earths three major internal layers?
Core, Mantle, and Crust
121
What makes up the lithosphere?
The uppermost mantle, along with the crust
