Introduction Lecture 1 - The Earth System Flashcards
Summarise the Stone Age
-Lasted 3.4 million years
-Humans learned how to use stones
-Facilitated hunting and other tasks
Summarise the Bronze Age
-Started around 6000-3000BC
-Humans learned how to extract metal from rocks (copper and tin to make bronze)
Summarise the Iron Age
-Started around 1200BC
-Humans start extracting iron to make steel tools
-Ended around 200BC-100AD
Summarise the Industrial Age
-Lasted from 1760-1970
-Fueled by coal mining which allowed us to harness steam energy; power tools and running water
-Population increased but so too did pollution
-This began anthropogenic climate change
Summarise the Oil Age
-1901-present
-Oil extraction to fuel economy; the world is now dependent on oil
Summarise the Space Age
-1957-present
-Lunar and potentially Martian exploration
-Satellite data is a huge industry and critical for resource management and mitigation/ planning of natural disasters
Summarise the Information Age
-1970-present
-Extraction of rare earths for computers and new technology
-Economy driven by IT
-The rise of AI and machine learning
Summarise the Big Bang
-First atoms (protons and neutrons formed in the first second)
-Hydrogen, helium and small amounts of lithium and berillium are formed
Summarise the first Star Formation
-Gasses come together under gravity
-Heat and pressure fuses hydrogen atoms to create helium (nuclear fusion)
-This fusion produces heavier elements all the way up to iron
Summarise the first Star Deaths
-Some stars go supernova and produce the rest of the elements in the periodic table
-Some of these heavier elements allow planet building and therefore life
Summarise the Formation of the Earth
-Asteroids and protoplanets collide to form a primitive Earth
-Asteroid impacts, planet formation and radioactive elements provide heat
-Planetary differentiation occurs
-Water is brought to Earth by asteroids and condenses due to Earth’s position inside the habitable zone
Explain Planetary Differentiation
-Heavier metals like iron and nickel sink to form the Earth’s core
-Lighter elements rise upwards, cool and condense to form the Earth’s crust
Explain how we obtained knowledge of the Earth’s interior
-Seisimic body waves (P and S) can travel through liquids (P waves also through solids)
-Changes in density cause the waves to refract
-Density increases with depth in the Earth
Outline the main layers of the Earth
-Crust
-Mohorovicic Discontinuity
-Lithosphere
-Asthenosphere
-Transition Zone
-Core (Outer and Inner)
Describe the Crust
-Outermost layer of the solid Earth
-Oceanic crust is basaltic, 1-10km thick
-Continental crust is granitic, 30-80km thick
Describe the Mohorovicic Discontinuity
-The boundary between the crust and mantle
Describe the Lithosphere
-This contains the crust and the rigid upper mantle
Describe the Asthenosphere
-Plastic (able to be molded and shaped)
-This is below the lithosphere
Describe the Transition Zone
-The boundary between the upper and lower mantle, around 660km deep
-Here, seismic waves change direction
Describe the Core (Inner and Outer)
Outer: -Liquid
-2900-5100km deep
-Earth rotation and
convection currents here
create the Earth’s magnetic
field
Inner: -Solid
-5100-6371km deep
-Single massive crystal of
iron and nickel
What is meant by Uniformitarianism?
-Natural laws and processes remain constant across space and time
Summarise the Rock Cycle
-Sediments come together through compaction and cementation to from sedimentary rocks
-Sedimentary rocks become metamorphic when exposed to heat and pressure
-Metamorphic rocks are melted into magma, and then condense to form igneous rocks
-Over time, igneous, metamorphic and sedimentary rocks are broken down, through weathering and erosion, to form sediments once more
