Geology
List the 4 most common minerals in Earth's crust.
Feldspar, Quartz, Amphibole, Pyroxene
List the rocky planets of our solar system and explain what a rocky planet is.
Mars, Venus, Mercury, Earth
Planets formed from denser elements and space junk, primarily solids we call rocks.
Explain what the Geologic Timescale is. What is an Eon? List the names of the Eons.
Its a way to divide the history of the Earth into pieces which are easier to talk about based on developments like plate tectonics, atmospheric changes, lifeforms evolving, mass extinctions, environmental changes, etc. Eons are the largest division of time, with there being 4 the Hadean, Archean, Proterozoic, and Phanerozoic.
What is an era? About how long is an era?
An era is a subdivision of Eons, they can last 10s to 100s of Millions of Years.
List the two main elements in the Sun.
H and He
List the 4 most common elements in the Earth's crust.
O, Si, Al, Fe
List the gas/ice giants of our solar system (saying which is which) and explain what a gas giant and ice giant is.
Gas - Jupiter, Saturn, Ice - Uranus, Neptune
Gas giants are closer to the sun and bigger, mostly formed from light H with a small amount of ice and He.
Ice giants are furthest from the sun, bigger than rocky planets but smaller than gas giants, mostly formed from light H and He, with significant ice and slush.
Explain when and how our Moon formed?
A protoplanet Theia collided with the very early Hadean Earth, the pieces of Theia and Earth that got smashed off orbited Earth as an asteroid belt before condensing into the Moon.
Describe and name the first types of life found on our planet.
Prokaryotes - (Bacteria and archaea) simple single celled organisms
Compare and contrast continental and oceanic crust.
Continental crust is lighter (more Si rich) thus more buoyant, so it "floats" higher. It's also typically thicker.
Oceanic crust is denser (more Fe and Mg rich) thus less buoyant, so it "floats" lower. Typically less thick.
Both are crust and can exist on the same tectonic plate.
Compare and contrast mineral and rock. Be sure to give a complete answer!
Rock - Made of minerals
Cookie Analogy - Rock is the cookie, minerals are the ingredients.
Describe where most of the mass of our SOLAR SYSTEM exists and why.
In the Sun! Over 90% of the material from the solar nebular went into forming the sun. All of our planets are just formed from the leftover stuff.
Explain why certain elements and minerals are in certain locations and how that has changed throughout time
Explain what cratons are and why they are so important to studying the Archean.
Cratons are pieces of continental crust from ancient Earth that can still be found today. They give us a tiny window into the past, since most rocks from the Archean have been destroyed by the rock cycle.
Explain how the Periodic Table is organized.
It is divided into Groups (columns) and Periods (rows) which are determined based on shared properties between elements. It is also in order by atomic number which is based on an element's number of protons. They are also divided into categories based on physical properties like Metals, Halogens, etc.
Describe the features used to identify different types of plate boundaries.
Convergent (subduction) - Volcanoes on overriding plate, earthquakes both deep and shallow, ocean trench, at least one oceanic plate
Convergent (mtn) - Mountains and two pieces of continental crust
Divergent - Youngest crust at boundary, getting older going away, mid ocean ridge, rift valley, shallow earthquakes
Transform - Zig zags cutting other features, shallow earthquakes
Explain how the solar system formed.
What is convection and how does it relate to what we see happening at the surface of the Earth at the end of the Hadean?
Convection is the movement of a substance due to differences in temperatures (like a lava lamp, hot things rise and cold things sink). In the mantle, the core heats nearby material, causing it to rise, as it approaches the crust it cools, and sinks back down. This is one driver of plate tectonics.
Explain what cyanobacteria are and how they led to an increase in free oxygen. How do we know when they existed?
Cyanobacteria were the first photosynthetic organisms. They are bacteria NOT PLANTS! Photosynthesis produced oxygen as a byproduct, increasing levels in the ocean and eventually atmosphere. We see stromatolites, which are trace fossils, as well as banded iron formations.
Explain how the first supercontinent Vaalbara formed and the evidence that implies its existence.
Plate tectonics in the Archean led to early continental crust smacking together forming a supercontinent. We see two cratons (Pilbara and Kaapvaal) in Australia and South Africa which are age dated to the same time and have matching rock types.
Describe the structure of the Earth (including compositional differences between layers).
Crust (solid, brittle, Si rich, cold)
Lithosphere (crust and very upper mantle, plate tectonics)
Asthenosphere (upper mantle more ductile, plates "float on" it, convection)
Mantle (not solid not liquid, very hot, Fe and Mg rich, convection)
Outer Core (liquid, Fe and Ni rich, extremely hot)
Inner Core (solid, Fe and Ni rich, high pressure extremely hot)
Explain why rocky planets are located closer to the sun and gas/ice giants further away from the sun.
The heavier elements weren't able to travel as far and also have higher condensation temperatures, which led them to form liquids and solids while still much closer to the Sun and start sticking together.
The lighter elements (H and He) were easier to push away and have lower condensation temperatures. The gas giants are still close enough that its hard to condense the volatile gases into ice. Ice giants are far enough away to be really cold and condense those.
What are the primary defining events of the Hadean?
Formation of Earth, crust begins to form as the earth cools, Moon forms, differentiation starts layering the Earth, cooling temps allow water to condense forming a global ocean, early plate tectonics may begin. No life yet.
Explain how banded iron formations formed and what they tell us.
Banded iron formations formed when Fe in the ocean reacted with free oxygen being produced by cyanobacteria. These formed iron oxide minerals which fell to the ocean floor creating a thin layer of red minerals. When oxygen was poor (due to ocean circulation and changing populations of cyanobacteria) silica minerals precipitate instead making black layers. It tells us when free oxygen first appeared, how oxygen varied, and when Fe in the oceans was mostly depleted.
Explain photosynthesis. What is the chemical reaction of photosynthesis?
Organisms that have developed chlorophyll can use it to get energy from the sun to break the bond between H and O in water molecules (H2O), it then bonds the H to CO2 creating a sugar (C6H12O6) and releasing the O that it doesn't need. It then uses the sugar as energy to live.