Studied by 314 PeopleOrder the layers of the Earth from top to bottom
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Order the layers of the Earth from top to bottom
Crust, mantle, outer core, inner core
Which layer of the Earth contains the geodynamo?
The outer core
What surface phenomenon expels water and gas to form the ocean and atmosphere?
Volcanism
Magma is a hot mix of different atoms. When it cools, some olivine minerals (Mg2SiO4) crystallize first. They form which rock?
Dunite
Igneous rocks form from the cooling of magma. What are examples of igneous rock?
Dunite, Granite, Basalt
In the following, which refers to a mineral, not a rock: Peridotite, Dunite, Olivine, Anorthosite
Olivine
One of the first minerals to form on rocky planets is anorthite, forming the plagioclase silicate rock anorthosite. What statement about anorthosite is correct?
It is lighter than typical mantle rocks
The second mineral to form massively on Earth was pyroxene, forming a rock that is now ubiquitous in the upper mantle. Which rock is it?
Peridotite
How does the rock basalt form?
By partial melting of peridotite, which eventually cooled into igneous rock
What is the most abundant rock at the surface of the rocky planets in the Solar System?
Basalt
What rocks are found at the Moon's surface, in particular in the Lunar Highlands and Mares?
Anorthosite (65%) and Basalt (35%)
Identify places on the Moon with a basaltic crust
The darker looking areas on the moon's surface
Basalt and Gabbro have the same composition, but different texture. Which one is Gabbro?
The glossier, sharper looking one (the one on the right of the image)
Even with the same composition, the aspect of lava flows differ by their temperature flow velocity. Which one is a'a flow?
The sharper, less smooth looking one (the one on the left of the image)
Order the elements of the oceanic crust from top to bottom
Sediments, pillow lava, sheeted dykes, gabbros
What is the typical density of the oceanic crust?
3 times that of water, 3,000 kg per cubic meter, 3 tons per cubic meter
What fraction of Earth's crust contains basalt?
About two thirds
How does granite form?
By cooling of magma depleted in magnesium and silicon
What is the average thickness of the continental crust?
35km
What is the average thickness of the oceanic crust?
6,000m, 6km, 6,000,000mm
What is isostasy?
A force that maintains continents above the seafloor, similar to buoyancy, the force that maintains lighter rocks above denser ones, a type of gravitational equilibrium
This is a bathymetric and topographic map of Earth. Click on a large region representative of the oceanic crust
The dark blue regions of the map
What are the three major types of rocks?
igneous, sedimentary, and metamorphic
What are the processes to create a sedimentary rock?
Compaction, cementation, and lithification
What features can help indicate a sedimentary rock?
The presence of fossils, bedding which occur by sediment deposition in layers, poorly sorted gran size (clasts of varying size)
Which type of rock forms by a change of state?
Igneous
What is the principle of uniformity (uniformitarianism) in geology?
The same processes and laws that we observe today also operated during Earth's history
What is an angular unconformity?
Angular contact between two rock strata of different ages
Where is the unconformity in the photograph?
The interface split between the high point and the low point
What is the difference between felsic and mafic magma and rocks?
Felsic rocks contain more silica than mafic rocks, mafic magmas, lead to effusive volcanism and felsic magmas, to eruptive volcanism, because of their high viscosity, mafic rocks have higher iron and magnesium content and look darker
What is called the layer of debris and unconsolidated materials between the bedrock and the atmosphere?
Sediment
Where is regolith found?
On all terrestrial planets and their moons
What is a difference between pressure and stress for a material?
Pressure represents equal forces in all directions, stress represents possibly different forces in different directions
What is true about metamorphic rocks?
All of igneous, sedimentary, and metamorphic rocks can experience metamorphism
What processes are related to metamorphism?
Diagnesis, foliation, recrystallization
Gneiss is a type of metamorphic rock. What type of metamorphism does it represent?
Intermediate-grade metamorphism (about 310 to 450 degrees Celsius and at moderate pressures)
What is the role of plate tectonics in the rock cycle?
Create sources and sinks, create new igneous rocks,recycles crustal material to the mantle
Iron (Fe) has an atomic number of 26 and an atomic mass of about 55. How many neutrons does it have?
29
Oxygen (O) has an atomic number of 8 and an atomic mass of 16. How many neutrons does it have?
8
Oxygen has an atomic number of 8. How many electrons does it have on its valence shell?
6
Why is noble gas chemically inert?
Because their valence shell is full
Hydrogen, lithium, and sodium are on the left-most column of the periodic table of elements. What type of ion do they form?
Cation
Fluorine and chlorine are in the penultimate column in the periodic table of elements. What type of ions do they form?
Anion
Here is a molecule of water with bonds between oxygen and hydrogen. What type of bond is that?
Covalent bond
Here is sodium chloride (NaCL) in solution. What type of electronic bond is involved?
Transferring of electrons
Here are the molecules of oxygen and the compound of methane. What type of bond is involved?
Sharing of electrons
What state of matter does plasma represent?
Highly compressive material that flows easily, made of electrically charged particles
What is the most common state of material in the universe?
Plasma
What is NOT a process of mineral formation?
Dissolution
What forces minerals to precipitate in an aqueous solution?
Change of temperature, change of chemical composition, evaporation
Stalactites are manifestations of which phenomenon?
Precipitation of calcite from groundwater
What is the first mineral to crystallize in a cooling primordial magma?
Olivine
Many organisms build bones, shells, and body coverings precipitating minerals biologically. What is the most common mineral formed this way?
Calcium Carbonate (CaCO3)
This thin section shows the silica shells of radiolarians, a type of zooplankton, in a chemical sedimentary rock. What is it?
Chert
What type of unconformity is on display in this Telheiro Beach, Portugal outcrop?
Angular unconformity
What is the wavy line between layers B and C in this block diagram?
Disconformity
What is the wavy line between layers G and H in this block diagram?
Angular unconformity
Order the stratigraphic layers A,B,C, and D from older to younger using the principle of superposition
A, B, C, D
Order the strata and geological events using the principles of stratigraphy
A, B, J, C, D, E, F, G, L, K, H, I
Radiometric dating of minerals is based on which physical principles?
The ratio of stable and unstable isotopes is a function of time, the atoms in the mineral must form a closed system, the proportions of stable and unstable isotopes evolve due to radioactive decay
The half-life of carbon-14 (14C) is 5730 years, as it decays to nitrogen-14. How many years does it take to decay half of carbon-14 (14C) atoms in a closed system?
5,730 years
The half-life of carbon-14 (14C) is 5730 years, as it decays to nitrogen-14. How many years does it take to decay 3/4 of carbon-14 (14C) atoms in a closed system?
11,460 years
The half-life of carbon-14 (14C) is 5730 years, as it decays to nitrogen-14. How many years does it take to decay all of carbon-14 (14C) atoms in a closed system?
An infinite time (it never truly happens)
During alpha decay, a type of radioactive decay, 2 neutrons and 2 protons are ejected from the parent isotope as an alpha particle, which also is a helium atom. What statement about the daughter isotope is correct?
The atomic number and the mass number decrease
During beta decay, a neutron in the nucleus of an atom splits into an electron and a proton, producing a beta ray. What statement is correct about the daughter isotope in Beta decay?
The mass number is unchanged, but the atomic number increases by one
Thorium-234 (234Th) decay to protactinium-234 (234Pa) is an example of what type of radioactive decay?
Beta decay
Carbon dating of organic material relies on the radioactive decay of carbon-14 (14C) to nitrogen-14 (14N). What is the source of unstable carbon-14 (14C)?
Interaction of nitrogen-14 (14N) with cosmic particles in the atmosphere
Order the eons of the geologic time scale (chronologically)
Hadean, Archean, Proterozoic, Phanerozoic
What marks the onset of the Phanerozoic eon?
The radiation of complex lifeforms
Order the eras of the phanerozoic (chronologically)
paleozoic, mesozoic, cenozoic
What happened at the Cretaceous-Paleogene boundary, or equivalently, at the end of the Mesozoic?
The extinction of non-avian dinosaurs
What is the current geologic epoch?
Holocene
What is the geologic period of alternating glaciations and interglacial periods?
Pleistocene
When did the Holocene geologic period start?
12,000 years ago
What is the life zone?
The region from 10km underground to 10km above the surface where all live organisms are found
What are the key characteristics of live organisms?
Metabolism, growth, reproduction, and evolution
Select organic compounds from the list
Nucleic acid (e.g., DNA, RNA), Carbohydrates, Lipids, Proteins, Oils
What are autotroph organisms?
Live organisms that derive their own food from inorganic sources, like minerals
What are heterotrophs?
Live organisms that feed from other living organisms or their byproducts
What is the dominant autotrophic process in Earth's biosphere?
Photosynthesis
What chemical reaction is enabled by photosynthesis?
Carbon dioxide combined with water produces sugars and releases oxygen
What are the two mechanisms of chemical growth?
Crystallization and polymerization
What is the energy budget of molecular growth?
Crystallization releases energy and polymerization consumes energy
What is the difference between DNA and RNA?
DNA stores the genetic material; RNA copies it and catalyzes protein synthesis