1. Structure of the Earth: The early geosphere, atmosphere and hydrosphere Flashcards
List all eight processes of the earth’s formation
- The Big Bang
- Nebula
- Shockwave
- Gravitational collapse
- Accretion
- Protostar
- Further accretion
- Ejection of remaining material
What was the big bang? When did it occur?
A spontaneous explosion which created all matter in the universe. The big bang occurred approximately 13 - 15 billion years ago.
What are quasars and how do they support the big bang theory?
Quasars are clusters of thousands of galaxies that occupy 1 light year’s worth of space.
Given their density, size and occupation of the surrounding space Quasars are only capable of being formed from an explosion as large and as intense as the big bang.
What is Cosmic Microwave Background Radiation
Cosmic Microwave Background Radiation is a small radio frequency prevalent in the universe.
What is redshift and how does it support the big bang theory?
Redshift is a law that states the further a celestial body is from the earth, the greater distortion in light there is. Scientists have observed that over time, light waves begin to distort, meaning that the universe is expanding.
What is a protostar?
A large ball of energy formed from accretion. The earth’s sun is an example of a protostar.
What was the nebula’s importance in forming the solar system?
The nebula contained material to form the planets.
What is catastrophism?
Large scale natural disasters defining the natural landscape of earth.
What is uniformitarianism?
The belief that the earth’s landscape was formed by smaller-scale, more frequent natural disasters.
Which view is generally accepted, catastrophism or uniformitarianism.
A combination of both views.
How was the atmosphere formed?
From volcanic emissions.
How was the hydrosphere formed?
The nebula which was disrupted by a supernova contained particles of ice in amongst the swirling dust cloud. Following the early earth’s formation, the ice particles were trapped underneath the earth’s surface, as the temperature was beyond boiling point.
It would take millions of years for the earth’s temperature to fall below 100 degrees, where water would finally evaporate, forming the oceans of today’s earth.
How was the geosphere formed?
During accretion, dummy.
What is the process of differentiation?
A chemistry term in which layers are ordered from densest to lightest.
What are seismic waves?
Waves that travel through the earth following an earthquake.`
What are the two types of seismic waves?
- Surface waves - Seismic waves that travel close to the earth’s surface.
- Body waves - Seismic waves that travel through the earth’s layers.
What are P and S waves?
Primary and Secondary waves
What is density formula?
Density = Mass / Volume.
What are the three basic descriptions of the earth’s structure?
- Crust
- Mantle
- Core
What are the four advanced layers of the earth’s structure.
- Lithosphere (Cool, tectonic plates)
- Asthenosphere (Hot, solid/liquid)
- Mesosphere (Largest volume)
- Core (Heat source)
What are the two categories of rock dating?
- Relative dating
2. Absolute dating
What is relative dating?
The arrangement of rocks in sequential order from appearance. Relative daring determines the age of a singular rock layer.
What is the law of superposition?
The youngest layer of rock is at the top and the oldest is at the bottom.
What is the law of cross-cutting?
Intrusions of igneous rock are younger than the rocks they cut through.
What is an unconformity?
A missing layer of rock due to erosion.
What is absolute dating?
Rock dating using radioactive isotopes to determine the exact age of a rock.
What is an isotope?
When there are more neutrons than protons in a nucleus.
What are the three assumptions of radiometric dating?
- The decay rate of the isotope is constant.
- The rock is a closed system (nothing can alter chemical compositiion)
- No daughter cell was present.
What are half-lives?
The time it takes for half of the nuclei in a parent cell to decay.
What are the two most common methods for dating carbon? (If possible, state how far in the past they can date)
- Carbon 14 is used in fossil dating to calculate the age of fossils as far as 5,730 years in the past.
- Uranium 238 is used in rock dating to calculate the age of rocks as far 4,510,000,000 years in the past. (nearly how long the earth has been in existence)
How are meteorites useful in rock dating?
Meteorites help understand the structure of the Earth.
What was the primary element in the earth earth?
Hydrogen.
When did the solar system form?
An estimated 5 billion years ago.
What is a protoplanetary disc?
Not to be confused with an accretion disc, a protoplanetary disc is a disc formed during the process of accretion, which created the entire solar system.
What were the components of the early atmosphere vs the atmosphere of today?
Early atmosphere: 200x the current rate of carbon dioxide, methane, hydrogen, sulfide.
Current atmosphere: Hydrogen dominated (though the concentration has remained that same as it was initially).
Describe the behaviour of a P wave. (2)
A P wave is the primary force of a tectonic collision and can travel through both solid and liquid.
Describe the behaviour of a S wave. (2)
An S wave is the secondary force of a tectonic collision and can only travel through liquid.
What is a parent element?
An element in it’s regular, unaltered state.
What is a daughter element?
The residual material of particle shedding.
How does Cosmic Microwave Background Radiation support the big bang theory?
There is not other way to rationalise the existence of these frequencies.
What insight do meteorites provide into the early Earth? (3)
- Material composition.
- Relative age.
- Seismic convection.
