Study sets, textbooks, questions
Upgrade to remove ads
GEOL Midterm 2
Terms in this set (117)
Order the layers of Earth from top to bottom
Crust, Mantle, Outer Core, Inner Core
Which layer contains the geodynamo?
The outer core
What surface phenomenon expels water and gas to form the ocean and atmosphere?
Magma is a hot mix of different atoms. When it cools, some olivine minerals (Mg2SiO4) crystallize first. They form which rock?
Igneous rocks form from the cooling of magma. What are examples of igneous rocks?
Dunite; Granite; Basalt; ALL OF THE ABOVE
Of the following, which refers to a mineral, not a rock?
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?
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?
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
Dark areas on the moon's surface
Basalt and Gabbro have the same composition, but different texture. Which one is Gabbro?
Rock with visible crystals and dark crystal chunks (right image)
Even with the same composition, the aspect of lava flows differ by their temperature flow velocity. Which one is a'a flow?
Sharper, rockier looking flow (on left of 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; ALL OF THE ABOVE
What fraction of Earth's crust contains basalt?
About two thirds
How does granite form?
By partial melting of the oceanic crust, which eventually cooled into an igneous rock of different composition
What is the average thickness of the continental crust?
What is the average thickness of the oceanic crust?
6,000m; 6km; 6,000,000mm; ALL OF THE ABOVE
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; ALL OF THE ABOVE
This is a bathymetry and topographic map of Earth. Click on a large region representative of the oceanic crust
Dark blue regions
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 grain size (class of varying sizes); ALL OF THE ABOVE
Which type of rock forms by a change of state?
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?
The area between two strata that is not the same
There is a famous road near the San Andreas Fault at Palmdale, California. Where is the unconformity?
The area between two strata that is not the same
There is an outcrop at Telheiro Beach in Portugal. Where is the unconformity?
The area between two strata that is not the same
What is the difference between felsic and mafic magmas and rocks?
Felsic rocks contain more silica than mafic rocks; Mafic rocks 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; ALL OF THE ABOVE
What is the layer of debris and unconsolidated materials between the bedrock and atmosphere?
Where is the regolith on this outcrop?
The sedimentary debris and pebbles and dirt
Where is regolith found?
On all terrestrial planets and their moons
What is the difference between pressure and stress for a material?
Pressure represents equal forces in all directions; stress represents possible 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?
Diagenesis; Foliation; Recrystallization; ALL OF THE ABOVE
Gneiss is a type of metamorphic rock. What type of metamorphism does it represent?
Intermediate-grade metamorphism (about 320 to 450C and at moderate pressures)
What is the role of plate tectonics in the rock cycle?
Create sources and sinks; Creating new igneous rocks; recycling crystal material to the mantle; ALL OF THE ABOVE
Iron (Fe) has an atomic number of 26 and atomic mass of about 55. How many neutrons does it have?
Oxygen (O) has an atomic number of 8 and an atomic mass of 16. How many neutrons does it have?
Oxygen has an atomic number of 8. How many electrons does it have on its valence shell?
Why are noble gasses 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?
Fluorine and chlorine are in the penultimate column in the periodic table of elements. What type of ions do they form?
Here is a molecule of water with bonds between oxygen and hydrogen. What type of bond is that?
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?
What is NOT a process of mineral formation?
What forces minerals to precipitate in an aqueous solution?
Change of temperature; Change of chemical composition; Evaporation; ALL OF THE ABOVE
Stalactites are a manifestation of which phenomenon?
Precipitation of calcite from groundwater
What is the first mineral to crystallize in a cooling primordial magma?
Many organisms build bones, shells, and body coverings by 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 rock is it?
What type of unconformity is on display in this Telheiro Beach, Portugal outcrop?
What is the wavy line between layers B and C in this block diagram?
What is the wavy line between layers G and H in the block diagram?
Order the stratigraphic layers A, B, C, and D from older to younger using the principle of superposition.
A (oldest), B, C, D (youngest) (bottom to top)
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; ALL OF THE ABOVE
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 the carbon-14 (14C) atoms in a closed system?
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 the carbon-14 (14C) atoms in a closed system?
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 the 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?
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
Hadean (oldest), Archean, Proterozoic, Phanerozoic (newest)
What marks the onset of the Phanerozoic eon?
The radiation of complex lifeforms
Order the eras of the Phanerozoic
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?
What is the geologic period of alternating glaciations and inter-glacial periods?
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 of 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?
A live organism that feeds from other living organisms or their byproducts
What is the dominant autotrophic process in Earth's biosphere?
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
What are defining characteristics of RNA (ribonucleic acid) bio-molecules?
RNA has the capacity to encode genetic material and catalyze chemical reactions
What promotes genetic variations during reproduction?
Genetic recombination in sexual reproduction; Random mutations (copies with errors); DNA damage; ALL OF THE ABOVE
What property of cellular reproduction or molecular replication enables evolution?
What are the characteristics of prokaryotes and eukaryotes?
Eukaryotes are more sophisticated cells and prokaryotes have more rudimentary functions; Prokaryotes reproduce asexually and eukaryotes reproduce sexually; All eukaryotes are aerobic cells, using oxygen respiration for metabolism; ALL OF THE ABOVE
What is the average lifespan of any single species?
What causes speciation?
Barriers to reproduction between different groups of a population; genetic variability and natural selection; Genetic drift by geographic isolation; ALL OF THE ABOVE
What are the driving factors of natural selection?
Competition with other species; Competition with other individuals; Environmental changes; ALL OF THE ABOVE
What is an important pre-requisite in a pre-biotic world for the emergence of life?
Availability of pre-biotic molecules, such as amino acids and carbohydrates
What are the possible physical environments where life emerged on Earth?
Hydrothermal systems near the seafloor called black smokers; Volcanic zones where heat, minerals, CO2, and water combine; Near the ocean surface where atmospheric CO2 and ocean water combine; ALL OF THE ABOVE
What is molecular evolution?
The combined result of variability and selection that allowed bio-molecules to perform function
When the solar system formed, where could we find the building blocks of life?
Virtually anywhere in the universe
What is molecular chirality?
Molecules of the same composition that come in mirror-image of each other; The property molecules to have different functions based on their geometry; The presence of compound with a left-handed and right-handed version; ALL OF THE ABOVE
In the context of the origins of life, what does the citric acid cycle represent?
Molecular self-replication; A reaction series that allows growth; Molecules of the citric acid cycle can be used to create bio-building blocks; ALL OF THE ABOVE
What property of lipids facilitated the emergence of a membrane surrounding the cell?
What mechanism enables template-directed synthesis to concentrate and select bio-molecules?
The non-uniform distribution of electrical charges in bio-molecules and mineral surfaces
What presumably explains the chirality of current life processes (left-handed amino acids and right-handed sugars)?
The reproduction of the first cell propagated the handedness of amino acids
What key property of RNA (ribo-nucleic acid) makes it a good candidate for being the first live molecule?
An RNA precursor may self-duplicate and encode genetic information
What metabolic process of cells enriched our tertiary atmosphere in oxygen?
What distinguishes prokaryotes from eukaryotes?
Prokaryotes cells are more rudimentary, with no membrane around the nucleus. They use asexual reproduction.
What mechanisms enhance genetic variability in prokaryotes?
Infection by virus; Contact with free genes from other prokaryotes; Exchange of genetic material with another prokaryote through the pilus; ALL OF THE ABOVE
How long did prokaryotes dominate the biosphere?
2 billion years
What lifeforms are descendants of eukaryotes?
Plants, animals, fungi, and protists
What key features of eukaryotes allowed the evolution of plants and animals?
Sexual reproduction; Respiration; The capacity of building three-dimensional colonies; ALL OF THE ABOVE
What is a mitochondria?
Mitochondria are organelles where biochemical processes of respiration and energy production occur
How old is the oldest living fossil indicating the presence of live organisms?
3.5 billion years old
What is the major evolutionary innovation developed by cyanobacteria during the Proterozoic?
Over the Proterozoic, photosynthesizing cyanobacteria, and eventually eukaryotes, exhaled oxygen during metabolism. What are the consequences for Earth?
The ocean was oxidized leading to the precipitation of iron oxides, and the formation of band-iron formations; The atmosphere was slowly oxygenated, and an ozone layer formed; Anaerobic bacteria were exterminated; ALL OF THE ABOVE
What evolutionary innovation was brought by eukaryotes during the Proterozoic?
Respiration (oxidation of carbohydrates with oxygen); Sexual reproduction; Biological cooperation leading to multi-cellular organisms; ALL OF THE ABOVE
In the context of Earth's climate, what is positive feedback?
A constructive reinforcement of cause and effect leading to amplification of either warming or cooling
What are the presumed causes of the first snowball Earth?
The burning of methane to form carbon dioxide by the slow release of oxygen by cyanobacterias
What is true about Ediacaran life?
Ediacaran fauna is the first fossil record of an animal-dominated ecosystem on Earth;
Ediacaran life is made of varied types of soft-bodied animals, like jellyfish and worms; Ediacaran-like fossils can be found all around the planet; ALL OF THE ABOVE
Sets found in the same folder
Lecture 12 - Precambrian Life
Lecture 24 - Global Anthropogenic Change
Planet Earth: Here We Go Again
GEOL 105 FINAL
Other sets by this creator
MUIN 425 TERMINOLOGY QUIZ
ALL GEOL 105 QUESTIONS
GEOL Midterm 1, GEOL Midterm 2, GEOL Mid…
Lecture 23 - Cenozoic History of Climate Change
Recommended textbook solutions
Abe Mizrahi, Edward E. Prather, Gina Brissenden, Jeff P. Adams
Andrew Fraknoi, David Morrison, Sidney C Wolff
Foundations of Astronomy
Dana E. Backman, Michael A. Seeds
Foundations of Astronomy
Dana E. Backman, Michael A. Seeds