Geology 1001 Final
How do minerals break if they do not have cleavage?
It breaks in a random and irregular fashion.
How can you explain why rain occurs when air rises?
- Evaporation occurs as water molecules escape as a gas from liquid water -High topography causes air mass to rise, cooling the warm, moist air leading to condensation leading to precipitation -Condensation occurs when water vapor molecules bind together to form droplets of liquid water
Hazards associated with different types of volcanoes/eruption styles/magma composition?
- Shield volcanoes (effusive eruptions): lava flows can be fast-moving and reach great distances, but generally not very explosive. - Stratovolcanoes (explosive eruptions): pyroclastic flows (hot ash, gas, and rocks) can travel at high speeds and devastate nearby areas; lahars (mudflows) can be triggered by volcanic activity and can travel long distances; ashfall can cause damage to infrastructure and harm to human health. - Calderas (explosive eruptions): massive explosions that can produce ash columns up to 50 km high and cause regional or global climate impacts; pyroclastic flows and lahars can also be produced. - Mafic lava flows (effusive eruptions): can move quickly and cover large areas, but generally not very explosive. - Felsic lava flows (explosive eruptions): can be very explosive, producing pyroclastic flows and ashfall that can impact a large region. Think of local vs global impacts: like what hazards are associated with lava flows verses a pycroclastic flow?
What defines the intrusive features: dikes, sills, laccoliths, batholiths?
A dike is a sheetlike intrusion that cuts across any layers present in the host rocks. Most dikes are steep because the magma pushes apart the rocks in a horizontal direction as it rises vertically and fills the resulting crack to form a dike. An intrusion that is parallel to layers in the host rocks is called a sill. Most sills are sub horizontal and form by pushing adjacent rocks upward rather than sideways. In some areas, ascending magma encounters gently inclined layers and begins squeezing parallel to them, forming a sill. The magma then begins inflating a lump-or bulge-shaped magma body called a laccolith. As the magma chamber grows, the layers over the laccolith tilt outward and eventually define a dome-shaped feature. A type of igneous rock that forms when magma rises into the earths crust, but does not erupt onto the surface is a batholiths. One or more overlapping plutons combine to form a massive igneous body.
What is a fracture and the difference between joints and faults
A fracture is a mechanical break in rocks involving discontinuities in displacement across surfaces or narrow zones. A joint is when a rock cracks where is it pulled apart. A fault is when rocks have slipped past one another, causing objects to be offset.
what is a pro tolith?
A protolith is the original rock that is transformed into a metamorphic rock during the process of metamorphism.
who proposed this hypothesis, and why was it rejected?
Alfred Wegener Continental drift hypothesis was rejected because he did not have explanation for the mechanisms driving continents across ocean
What are hot spots, how do they form? And know an example.
An area on earth over a mantle plume or an area under the rocky outer layer of earth, called the crust, where magma is hotter than surrounding magma Causes melting and thinning of the rocky crust and widespread volcanic activity The Hawaiian islands
What are ions?
An atom or molecule with a net electric charge due to the loss or gain of one or more electrons
What are tsunamis?
An earthquake beneath the ocean can cause a large wave called a tsunami. They are waves generated by a disturbance in the sea or much less commonly in a lake. They are generated by abrupt changes in water level in one area relative to another.
What are the differences of the three types of unconformities?
Angular Unconformity: erosional surface with flat/horizontal rock layers above and tilted rock layers below Nonconformity: erosional surface between Sedimentary rocks and crystalline rocks Disconformity: erosional surface between sedimentary rocks Deposition of horizontal layers Weathering erodes surface Eroded surface covered by later sediment
How does crystal size and metamorphic fabric (foliation degree) relate to metamorphic grade?
As metamorphic grade increases, crystal size tends to increase and the degree of foliation (metamorphic fabric) also increases. This means that rocks that have undergone higher metamorphic grades will typically have larger crystals and a more pronounced foliation than those with lower grades.
What dominant type of stress and faults are associated with the three types of plate boundaries?
At divergent plate boundaries, tensional stress is dominant, which can cause normal faults to form. At convergent plate boundaries, compressional stress is dominant, which can cause reverse/thrust faults, or sometimes strike-slip faults. At transform plate boundaries, shear stress is dominant, which can cause strike-slip faults to form.
Know the basics of elements
Atoms - the smallest individual particles showing all distinctive properties of a chemical element Nucleus: contains protons and neutrons The nucleus contains most of the mass of the atom Number of protons can never change for an element But an atom of an element can have a different number of neutrons (=isotopes) or electrons (=ions) Size of an ion= outer edge of its electron cloud
What is recurrence interval?
Average time between repeating earthquakes
Why are banded iron formations never younger than 1-1.5 billion years old?
BIFs stopped forming about 1.8 billion years ago when earths atmosphere finally became saturated with oxygen and took on a composition more like what we know today
Why do we have uneven solar heating of earth's surfaces at different latitudes?
Because the angle of radiation varies depending on the latitude, surface temperatures on a average are warmer at lower latitudes and cooler at higher latitudes
What are the two types of fossils.
Body fossils Remains of the actual organism that have been altered Direct evidence of past life Durable and inedible hard parts - bones, teeth, shells > mineral replacement They can leave cast or molds Trace fossils Evidence of organisms behavior Indirect evidence of past life Footprints or burrows of worms Trace makes Bite and tooth marks
What is the difference between seismic body waves and seismic surface waves?
Body waves: travel throughout the earth Surface waves: only travel the upper few kilometers The most dangerous and destructive They move the earth a lot more compared to body waves
What are the common non-silicate mineral groups? And examples.
Carbonates and the most common are calcite and dolomite. Oxides and this is hematite, and magnetite. Sulfides which is pyrite, and galena. Know basic chemical formula (anionic complex) that define the common groups of minerals. Such as carbonates are defined by having CO3, silicates having SiO4....
Are earthquakes in mid-ocean ridge settings typically deep or shallow, strong or weak? Why?
Characterized by shallow, small magnitude earthquakes Because crust is hot and very thin, large or deep earthquakes are not possible What about convergent boundaries (subduction zones and continental collisions)? Earthquake size/magnitude relationship to amount of displacement, rupture size, length of time ground shaking
Why is this current climate change so concerning?
Climate change has many potential impacts Ranging from an increase in global temperatures to a possible increase in certain diseases. Melting of snow and ice resulting in glaciers melting back and become less extensive. Desertification due to higher temperatures. Etc.
What are common felsic and mafic silicate minerals?
Common mafic minerals are amphibole, pyroxene, olivine, garnet, and biotite. Common felsic minerals are quartz, potassium feldspar, plagioclase and muscovite.
Know the most common numeric dating technique (isotopic dating method)
Common numeric age dating Tree rings Dendrochronology: dating of wooden objects by counting growth rings - Varies - layers of sediment - Ice Cores
What is the differences between Contact metamorphism and Regional metamorphism? What causes each?
Contact metamorphism is a type of metamorphism where rock minerals and texture are changed, mainly by heat, due to contact with magma. Regional metamorphism is a type of metamorphism where rock minerals and texture are changed by heat and pressure over a wide area or region.
generally what type would you expect with which metamorphic setting (contact, regional, hydrothermal)
Contact metamorphism typically results in non-foliated textures due to the localized heating and pressure from intruding magma. Regional metamorphism usually results in foliated textures due to the regional-scale pressure and deformation from tectonic forces. Hydrothermal metamorphism can result in either foliated or non-foliated textures, depending on the conditions of the fluid and the host rock. The fluids can introduce new minerals or alter existing ones, leading to the formation of new textures.
What type of differential stress, what type of fault is most common, where metamorphism occurs, and what type of metamorphism
Convergent Plate Boundaries: Differential stress is compressional. Reverse faults are common. Metamorphism occurs in the subduction zone and can be regional or contact metamorphism. Divergent Plate Boundaries: Differential stress is extensional. Normal faults are common. Metamorphism is less common but may occur in rift zones and can be regional or contact metamorphism. Transform Plate Boundaries: Differential stress is shear. Strike-slip faults are common. Metamorphism may occur in fault zones and can be localized or regional metamorphism. Hotspots: Differential stress is not as important as heat and pressure. Faulting is less common. Metamorphism occurs near magma intrusions and can be contact or regional metamorphism.
What is a high pressure zone? Does air diverge or converge? Does it flow down or up relative to Earth's surface?
Converging air currents Compress air-> increasing air pressure Cloudless, sunny skies
What are the four ways atoms can bond to form minerals?
Covalent bonding Produced from a sharing of one or more electrons The STRONGEST bond Ionic bonding Produced from a transfer or loaning go on or more electrons for optimal outer shell occupancy Elements with significantly different electronegativity tend to produce ionic bonds MODERATE bond NaCI - table salt To obtain stability, atoms may give up, borrow or share electrons Metallic bonding Produced from a sharing of electrons between many atoms Electrons are very loosely connected to their nucleus Move easily throughout the structure Free to roam Tend to be good conductors of heat and electricity WEAK bond Common in minerals involving transition metals Inter-molecular force bonding Produced from intermolecular attractions; attractions between one molecule and a neighboring molecule Weak secondary attraction bonds between electrically neutral molecules that have one positive end and one negative end WEAKEST bond
Be able to identify cross-beds and what do they indicate?
Cross-beds are inclined layers of sediment that are deposited at an angle to the horizontal bedding plane. They indicate that the sediment was deposited by wind or water currents, and the angle of the cross-beds can help determine the direction of the current. Cross-beds are commonly found in sandstones and other sedimentary rocks that were formed in environments with flowing water or wind. What are the three categories of depositional environments and be able to provide examples of continental(terrestrial), transitional(marginal), and marine environments The three categories of depositional environments are continental, transitional, and marine. Continental (terrestrial) environments include places where sediment accumulates on land such as deserts, rivers, lakes, and glaciers. Transitional (marginal) environments occur where land meets the sea, such as deltas, estuaries, and beaches. Marine environments occur in the ocean and include environments such as reefs, continental shelves, and deep ocean basins.
What are the diagnostic properties/clues of minerals that help geologists identify minerals?
Crystal form Color Cleavage When a mineral can break along a certain plane A plane of weakness No cleavage Luster How light is reflected off of a minerals surface
What are the three ways minerals can form? we covered this in class
Crystallization from a melt As magma and lava cools, elements combine to form minerals= igneous rocks Precipitation from a solution Elements dissolved in a solution may crystallize out if they become abundant enough and crystals can also precipitate out from mineral-rich groundwater Solid-state solution Atoms can diffuse very slowly through solids, given high pressure and elevated temperature condition until they rearrange themselves into a new mineral Metamorphic rocks
What is valence state electronegativity? And how does it relate to covalent and ionic bonds?
Describes an atom's ability to attract electrons, influences how atoms bond Elements with similar or equal electronegativity produce covalent bonds Cations have net positive charge due to more protons than electrons Electrons with low electronegativity= tend to give up electrons becoming cations Anions have net negative charge due to more electrons than protons Electrons with high electronegativity = strong tendency to attract electrons with cations Increased from left to right in the periodic table
How do we use fossils to infer the age of rocks?
Determine relative age of different rock layers Assign the rock a geologic period Correlate stacks of strata between various locations Help in interpretation of past environments
When did Earth form and what is the evidence for its age?
Earth formed 4.6 ~ 4.5 billion years ago The evidence for its age is isotopic ages of meteorites, dated moon rocks, and earth rocks
What do each type of environmental indicator in sedimentary rocks tell us about its depositional environment?
Different environmental indicators in sedimentary rocks can provide information about the depositional environment: - Color: Color variations can indicate the presence of different minerals or chemical conditions in the environment, such as the presence of iron oxide in red sedimentary rocks. - Grain size and sorting: Coarse-grained sediments generally indicate high-energy environments, such as rivers or beaches, while fine-grained sediments suggest low-energy environments, such as deep ocean basins. Well-sorted sediments suggest consistent and uniform transport, while poorly sorted sediments indicate varying transport energies. - Clast shape: Angular clasts suggest a shorter transport distance, while rounded clasts suggest longer transport distances. - Fossils: The presence of fossils can indicate the type of organism that lived in the environment, as well as the environmental conditions that supported their growth and survival. However, it is important to note that each indicator must be considered in combination with others and in the context of the overall sedimentary rock formation to fully understand the depositional environment.
Know the metamorphic and deformation processes for various tectonic settings
Different tectonic settings can lead to different types of metamorphism and deformation: Convergent Plate Boundaries: Collision of two plates can lead to regional metamorphism and folding or faulting. Divergent Plate Boundaries: New crust is created as plates move apart, so metamorphism is less common but normal faulting and block tilting can occur. Transform Plate Boundaries: Shearing and deformation can occur due to horizontal movement of plates. Hotspots: Magma rising from the mantle can cause metamorphism and deformation due to heat and pressure.
Know the global atmosphere circulation and wind patterns
Differential solar heating at different latitudes is doe to the earths curvature At higher latitudes, the suns rays hit earth at an angle resulting in same amount of sunlight as equator but disperses across a larger sea Less intense sunlight at poles, more intense at equator Distributes uneven heated air from equator to the poles, regulates global air temperatures
The difference between direct, historical, and paleo-proxies evidence for climate change.
Direct measurements - instruments Using instruments like thermometers and satellites Historic evidence - written or oral Paleo-climate proxies - geologic evidence
What is a low pressure zone? Does air diverge or converge? Does it flow down or up relative to Earth's surface?
Diverging air current move air away Rising air= as it cools it causes condensation Clouds forming and sometimes precipitating
What is a half-life and percentages of parent to daughter/child atoms after 1,2,3 half-lives?
Each original isotope, called the parent, gradually decays to from a new isotope, called the child or daughter Before decay, all unstable parent atoms After one half-life 1/2 the parent atoms decayed to child atoms (time=half-life) After a second half-life, only 1/4 of the parent atoms remain After a third half-life, only 1/8 of the parent atoms remain
What is the goldilocks zone and why is it important?
Earth is in the goldilocks zone and the conditions allow for water and atmosphere which are ideal for life
What is the Coriolis effect? And how does it affect travel going north or south?
Earth rotating eastward Faster velocity near equator Air flowing toward poles moving faster than ground; appears to deflect to right Air flowing away from poles moving slower than ground; appears to deflect to right Opposite in southern hemisphere (deflects to the left)
How is earthquake magnitude related to frequency?
Earthquake size and frequency have an inverse relationship
What is Seafloor spreading?
Earths crust separates along mid-ocean ridges New seafloor crust is created at this ridges Newly formed seafloor crust moves laterally, away from the ridge
How did Earth's layers form? What is the process?
Earths layers formed by differentiation, which is the process in which a primitive planetary interior, composted of a uniform distribution of material, separates into layers of different density Dense materials sink to the center and light materials float to the top
What are the 5 components/spheres that make up Earth's system?
Earths system is the sum of the physical, chemical, and biological processes operating on and within the earth The sub-systems include Geosphere (lithosphere) - solid earth - rocks and soil/regolith. Atmosphere - gaseous envelope surrounding the earth Biosphere - all living organisms Hydrosphere - all earth on water - liquid Cryosphere - all frozen water
What is the difference between effusive and explosive eruption styles?
Effusive eruptions are relatively gentle, and lava flows out of the volcano in a slow and steady manner, often forming shield volcanoes. Explosive eruptions are more violent, and involve the sudden release of gases and magma, often creating stratovolcanoes. Explosive eruptions can also produce ash, pyroclastic flows, and lahars, which can be dangerous to nearby communities.
What are unconformities?
Erosion on a landscape created an Unconformity Erosional surfaces can be buried and represent 'missing time' in the rock record
What are examples of effusive or explosive volcanic eruptions?
Examples of effusive volcanic eruptions include the ongoing eruption of Kilauea in Hawaii and the 2014-2015 eruption of Bardarbunga in Iceland. Examples of explosive volcanic eruptions include the 1980 eruption of Mount St. Helens in the United States and the 1991 eruption of Mount Pinatubo in the Philippines.
Difference between an extinction and a mass extinction
Extinctions affecting one or few species and occurring locally rather than globally belong to a pattern known as background extinction. The fossil record, however, describes sudden, global extinctions that affect many species. These dramatic events are known as mass extinctions.
What does intrusive and extrusive igneous rock mean?
Extrusive igneous rocks- form when magma is erupted onto earths surface as lava, solidifying above the surface Intrusive igneous rocks- form when magma solidifying below the surface
What are the different types of faults and what type of stress is associated with each
Faults are fractures along which rocks gave slipped. A dip-slip fault is when slip along a fault can be parallel to the dip- one block moves up or down relative to the other block, strike-slip fault can occur in a horizontal direction, parallel to the strike, a oblique-slip fault is when a slip along a fault is not parallel to neither the dip or the strike. The main types of faults are normal faults, reverse faults, and strike-slip faults. If the hanging wall moves down relative to the football, the fault is normal. If the hanging wall moves up relative to the football, the fault is a reverse fault. Both normal and reverse faults are considered dip-slip faults. Strike-slip faults consist of left and right lateral faults. When rocks along a fault move with side-to-side motion, parallel to the strike of the fault surface, the fault is a strike-slip fault. If the opposite side is displaced to the left across the fault, this is a left-lateral fault. If the opposite side of the fault is offset to the right, the fault is a right-lateral fault.
What is stick-slip behavior?
Faults have a "stick-slip behavior" because rocks are resistant to movement, when stress gets too much for the rocks, they slip-> faults rupture When the rock slips, they release energy in the form of an earthquake
Is mafic or felsic magma more viscous and why?
Felsic magma contains more silica and alumina content, which makes magma more vicious. Know the igneous environments. Where and how melt forms. For example, mid ocean ridges have basalt and gabbro igneous rock form from mafic magma compositions due to mantle melt as a result of decompression melting.
What are the major differences between felsic, intermediate, mafic, and ultramafic igneous rocks? (hint, the silicate minerals in Bowen's reaction series)
Felsic rocks are light in color, high in silica content, and found in continental crust. Intermediate rocks have a mixture of light and dark minerals. Mafic rocks are dark in color, low in silica content, and found in oceanic crust. Ultramafic rocks are very low in silica content and composed mostly of dark-colored minerals, found in mantle areas.
Know the relationship between silicate crystallization order and order of melting (do felsic silicate minerals (like quartz) melt before mafic silicate minerals (like olivine)?
Felsic silicate minerals like quartz have higher melting points than mafic silicate minerals like olivine, so they generally melt after mafic minerals. The order of crystallization and melting of silicate minerals is related to their chemical composition and melting points.
How can flood basalt eruptions cause extinction events?
Flood basalt eruptions can cause extinction events through the release of large amounts of volcanic gases such as sulfur dioxide, which can lead to acid rain and a cooling effect on the planet. This can have devastating impacts on the environment, including disrupting ecosystems and causing mass extinctions of species. The cooling effect can also lead to changes in sea level and ocean currents, which further exacerbate the impacts on life.
How can we use seismic waves to determine the magnitude of an earthquake?
For local magnitude: measure S-wave amplitude Connect amplitude and distance on plot
How are igneous rocks formed?
Formed from cooling and solidification of magma and lava
What is an index fossil?
Fossils with short age span, widely distributed and are abundant They help to date and correlate strata (rock layer) that the fossils are found in
Know the different types of physical weathering
Freeze-thaw: water in cracks freezes and expands widening cracks and prying rocks apart Thermal expansion: temperature changes cause rocks to contract and expand Fracturing: gravity pulling rocks away from a steep cliff or from unloading, less overlying weight at/ near-surface Biological activity: Root wedging, pries rocks apart Animals moving material to surface Biological activity can also chemically weather rock too Freeze-thaw: water in cracks freezes and expands widening cracks and prying rocks apart Thermal expansion: temperature changes cause rocks to contract and expand Fracturing: gravity pulling rocks away from a steep cliff or from unloading, less overlying weight at/ near-surface Biological activity:
What are weather fronts and the three types?
Fronts are boundaries between two types of air masses, such as a warm, humid one and a cold, dry one Cold front: cold air moves and displaces warmer, moist air Warm front: warm air moves and displaces colder air Stationary front: boundary between warm and cold air, but not moving for hours or days
What are some ways geology influence our lives and where we live?
Geologic features determine whether a site is safe from landslides, floods, and other natural hazards. Important clues to this is whether a volcano is near or a steep slope that could collapse as a landslide and destroy everything. This could also play a part in whether your house would be safe to build on this soil. Areas along rivers are more desirable because rivers replenish nutrients but also pose a problem if the area is to low because it could lead to flooding.
Why do geologists map out and analyze lava flows, lahars, pyroclastic deposits and ash layers(tephra)?
Geologists map and analyze lava flows, lahars, pyroclastic deposits, and ash layers to understand the past eruptions of a volcano and to predict its future behavior. By studying the extent and distribution of these deposits, they can reconstruct the eruptive history of a volcano and determine the frequency and style of past eruptions. This information can then be used to assess the potential hazards of future eruptions and develop plans to mitigate their impact on people and infrastructure.
Global deep ocean circulation: what controls the ocean conveyor belt vs the surface currents?
Global circulation of surface and deep water driven by temperature and salinity Thermohaline circulation, the oceans "conveyor belt" links major surface and deep-water currents in the Atlantic, Indian, pacific, and southern oceans
What are the differences between a gneiss and marble?
Gneiss is a banded metamorphic rock with layers of different minerals, while marble is a non-banded metamorphic rock made primarily of calcite or dolomite minerals.
What are the three factors that help in fossil preservation?
Hard parts- more difficult to break down or less likely to be eaten Rapid burial- less time scavengers and other processes have to destroy or eat specimen Low oxygen environment- slows decay, no bacteria or organism that require oxygen
What are tests that can be done to minerals to help identify them?
Hardness Scale 1-10 Hardest mineral is a diamond Softest is talc Effervescence Bubbling reaction Streak Magnetism Density Heft test or specific gravity
Know the different types of chemical weathering,
Hydrolysis Silicate minerals are exposed to water and natural acids, converting original materials to ions dissolved in water and clay minerals Feldspar minerals -> clay minerals + dissolved ions Dissolution Some minerals (ex: calcium carbonate) dissolve completely into dissolved ions in water Reaction with rain, ground water Dissolution is often focused in fractures Oxidation When exposed to Earth's atmosphere, some minerals become unstable (iron-bearing minerals) When combine with oxygen they form oxide minerals Mafic silicate minerals -> iron oxides Biological
How do the minerals cleave when they have 1, 2, or 3 cleavage planes.
If a mineral has a single direction of cleavage, it cleaves along one set of parallel planes, forming thin sheets. Minerals that cleave along two sets of planes that are perpendicular to one another. This type of cleavage results in right-angle steps along broken crystal faces. Two planes of cleavage can intersect at angles other than 90 degrees. Minerals with this type of of cleavage can break into pieces having corners that do not form right angles. If a mineral cleaves along three perpendicular sets of planes, broken faces have a stair-step geometry and the mineral commonly breaks into cubes, as is typical of halite. Minerals that cleave along three directions of planes that are not mutually perpendicular break into piece that are shaped like a rhomb or a sheared box.
What is the relationship between cooling rate and crystal size?
If the magma cools quickly, the crystals do not have much time to form, so they are very small. If the magma cools slowly, then the crystals have enough time to grow and become large.
Be able to identify the three types of folds if provided a picture
If the rock layers warp up in the shape of an A, the fold is generally called and anticline. If rocks fold in the shape of a V or U, the fold is generally called a syncline.A monocline, a name that indicates the fold only has one dipping segment.
What is the difference between a hanging wall and footwall (only for dip-slip type of faults).
In a dip-slip fault, the football is below the fault plane and the hanging wall is above the fault plane.
What are some impacts to our current climate change that we've observed so far?
Increase in global average air temperature beginning ~ 1890 1.8 degrees change in F
Be able to identify examples/know the difference between observation, measurements, and interpretation.
Interpretations based on the qualitative and quantitative date and any prior knowledge, you can form a conclusion or inference With interpretations, explanation are required Explanations = hypotheses
How is Earth's magnetic field generated?
Iron rich Outer core - electrically conducting fluid in constant motion generating the Earth's magnetic field called the dynamo effect
What is isostasy?
Isostasy explains most of the variations in elevation from one region to another, and it is commonly paraphrased by saying mountain belts have thick crustal roots.
What can isotopic dating tell us about the rock analyzed?
Isotopic dating tells us the numeric ages which determines when rocks were formed When some rocks passed through certain temperatures When sediments were deposited When a volcanic rock deposited A numeric age obtained for the volcanic layer can help constrain the ages of the sedimentary layers on either side of the volcanic units
What are two main controls on magma viscosity?
Its controlled by its temperature, composition, and gas content
what environment would you expect to see large angular clasts vs muds
Large angular clasts are typically associated with high-energy environments such as fast-moving rivers, glaciers, or steep slopes. Muds, on the other hand, are usually found in low-energy environments such as lakes, lagoons, or the deep sea where there is little to no current or wave action.
How can large volcanic eruptions cause climate change?
Large volcanic eruptions can cause climate change by injecting sulfur dioxide and other particles into the stratosphere, where they can reflect sunlight back into space and cool the Earth's surface. This can lead to a temporary cooling effect on the planet, affecting global weather patterns and leading to changes in climate.
What four principals we covered in lecture do geologist use to determine sequence of past geologic events?
Law of superposition, cross-cutting relationships, law of included fragments, and contact effect
Know what lithification is and the two processes of lithification
Lithification is the process by which loose sediments are converted into solid sedimentary rocks. The two processes of lithification are compaction and cementation. Compaction is the process by which sediments are squeezed together by the weight of overlying sediments or water. The pressure exerted on the sediments removes water and air, resulting in the reduction of the volume of sediments. Cementation is the process by which minerals precipitate from water, filling in the spaces between the sediment grains. This process glues the sediment grains together and forms a solid rock. The mineral that precipitates from water can be silica, calcite, iron oxide, or other minerals depending on the chemical composition of the water.
What are the differences between the Asthenosphere and Lithosphere?
Lithosphere - crust and upper mantle - strong, cold brittle Asthenosphere - portion of the mantle directly below the lithosphere - weaker, warmer, ductile
What does low vs high grade indicate?
Low-grade rocks tend to be fine-grained and high-grade rocks tend to be coarse grained.
How can mafic magma compositions evolve to felsic compositions?
Mafic magma can turn into felsic magma through a process called fractional crystallization.
What are the three ways melt can form?
Magma can form in three ways: partial melting of solid rock, fractional crystallization, and mixing of magmas.
How is the Earth's magnetic field generated?
Magnetic field is generated by convection, rotation of iron-rich liquid outer core
How are these magnetic stripes on the seafloor formed?
Magnetic stripes represent the changed direction of the magnetic pole
What does the magnitude of earthquakes refer to?
Magnitude of an earthquake refers to the amount of energy released
How can mantle plumes within tectonic plates for either flood basalts or claderas?
Mantle plumes within tectonic plates can cause flood basalts or calderas by melting the rock above them and creating a large volume of magma that can erupt onto the surface. The magma can either flow out in a series of lava flows, creating a flood basalt, or it can erupt explosively, causing the ground to collapse and form a caldera.
What's the parent rock of: a marble? Green-schist? Quartzite? A gneiss which had metamorphically evolved as slate to phyllite too schist to a gneiss?
Marble: The parent rock of marble is limestone or dolomite. Green-schist: The parent rock of green-schist is usually a mafic igneous rock such as basalt or gabbro. Quartzite: The parent rock of quartzite is usually a quartz-rich sandstone. Gneiss: The parent rock of gneiss can vary, but in the example given, it would be shale or mudstone that metamorphosed to slate, then to phyllite, and eventually to schist before becoming gneiss.
What is Metamorphic grade?
Metamorphic grade is the general term describing the relative temperature and pressure conditions under which metamorphic rocks form.
How are metamorphic rocks different than igneous and sedimentary rocks?
Metamorphic rocks are formed from other rocks that are changed by heat and pressure underground. Igneous rocks are formed from melted deep rock inside the earth and sedimentary rocks are formed from layers of sand, silt, etc.
Know what the metamorphic textures, foliation, non-foliated, and Schistosity mean
Metamorphic textures are the physical features of a rock that has undergone metamorphism. Foliation is a texture where mineral grains align in the same direction, creating a striped appearance. Non-foliated is a texture where there is no obvious alignment of mineral grains or layers. Schistosity is a type of foliation where visible, elongated minerals are aligned in parallel.
What are the chemical and physical processes that a rock undergoes during metamorphism?
Metamorphic undergoes two different types of processes, physical and chemical. The physical processes being deformation of objects, rotation, and shearing. Deformation of objects is when rounded grains can become flattened in the direction of maximum stress. Rotation is when minerals that crystalize or grow in the differential stress field can have a preferred orientation. Shearing stress causes objects to be smeared out in the direction of applied stress. Chemical processes are recrystallization, remobilization, and pressure solution. Recrystallization is when existing minerals can recrystallize into larger crystals or new minerals can grow during metamorphism. Remobilization is when various minerals in the rock can partially melt then concentrate in areas of rock- producing light and dark bands. Pressure solution is when material dissolved from highly stressed edges of grains.
What is mineral cleavage?
Minerals cleavage is determined by the atom arrangement and strength of atom bonds Minerals with cleavage can cleave into blocks or sheets along the weaker cleavage planes
What are the five rules that a mineral must meet to be a true mineral?
Naturally occurring and found in nature Solid, crystalline substance Have a well-defined chemical composition and have a regular atomic arrangement: atoms are arranged in orderly and repetitive patterns Regular atomic arrangement: atoms are arranged in orderly and receptive patterns Must be inorganic
Are all continental margins plate boundaries? What is a passive versus an active continental margin? What feature is diagnostic of passive margins?
No, a passive margin is not associated with a plate boundary. A passive margin faces a divergent plate boundary MOR Active margin faced a convergent plate boundary - subduction
Do the seismic waves cause all the damage that can happen when an earthquake occurs? What are some other hazards that can be associated with earthquakes?
No, other hazards are liquefaction; when solid ground becomes soft it can lead to buildings sink in. Fires can start when electrical and gas lines are dislodged due to earths shaking. Also, tsunami and major flooding such as dam failure.
What are the compositional layers of the Earth? And their average composition?
Oceanic crust - basalt Continental crust - granite Mantle - olivine Core - iron and nickel Outer core - liquid Inner core - solid
Why does oceanic crust sit lower than continental crust?
Oceanic crust is thinner than continental crust and consists of denser rock than continental crust. A region of earth that consists of dense crust is lower in elevation than a region with less dense crust.
What's an ophiolite?
Ophiolite's are slices of oceanic crust on land.
What are the two most abundant elements in Earth's crust? How does this relate to the most common rock forming mineral?
Oxygen and Silicon. This relates to the most common mineral of silicate because that is what is composed of.
What are the 8 most abundant elements that make up Earth's crust and Earth as a whole?
Oxygen, Silicon, Aluminum, Calcium, Iron, Magnesium, Sodium and Potassium.
Know the names of the three eras of the Phanerozoic eon
Paleozoic Era Mesozoic Era Cenozoic Era (current)
At what scale do tectonic plates move on average in a year?
Plates move 1-15 cm per year
Know what the two eons of earth's history are called
Precambrian Eon: 88% earth's history Phanerozoic Eon (meaning "visible life"): 12% earths history
Know the key fossils that define Precambrian, Paleozoic, Mesozoic, Cenozoic
Precambrian- hellish/ alien universe Molten ball of rock - magma ocean Rock contained stromatolites Cyanobacteria had produced enough oxygen through photosynthesis to increase the amount of oxygen in the atmosphere and from a protective ozone layer Paleozoic- extraordinary diversity of life evolved 1st fish, amphibians, insects, reptiles, land plants Coral, mollusks, trilobites, snails, shelled creatures with tentacles Middle: fish became diverse, large reefs of coral 1st on land - plants ferns, seedless trees, insects Late: 1st vertebrate animals on land Amphibians and early reptiles evolve Seedless plants became widespread on land Mesozoic - the age of reptiles - Dino Along with Dinos, 1st birds: mammals appeared Early: Triassic small Dino creatures, early mammals, seed-braving conifers Middle: Jurassic, dinos diversified, seas flourished with ammonites, star fish, large marine reptiles Late: Cretaceous, flying reptiles, large Dinos T-rex living End of the Mesozoic: Dino populating declining Extensive volcanic activity Global temperatures falling Sea level drop Cenozoic- The age of Mammals Began with the extinction of the non-avian Dinos Mammals diversified and dominated the animal kingdom Diversification of plants, insects etc Animals looked more familiar Early: appearance of bats, rodents, primates, sloths, whales, hoofed animals, marsupials, small horses Appearance of flowering plants, and grasses Early primates Monkey and ape Late: appearance of humans
How do seismologists determine if there is a high risk of an earthquake?
Prehistoric earthquakes, historic accounts
What are climate proxies?
Preserved characteristics in the rock record that can be used to reconstruct past climate conditions Proxy date: data not strictly climatic but that can be correlated
How does pressure influence melting of rocks? Why is mantle rock a weak solid and not a melt even though temperatures are hot enough?
Pressure raises the melting point of rocks. The mantle rock is a weak solid and not a melt even though temperatures are hot enough because the high pressure in the mantle inhibits melting. The pressure increases with depth in the Earth's mantle, which raises the melting temperature of the mantle rock. This means that even though the temperatures are hot enough to melt the rock, the high pressure keeps the rock in a solid state. The mantle rock can become a melt if the pressure is reduced, such as when it rises to shallower depths or if there is a decrease in pressure due to tectonic activity.
What are the two types of body waves and how do they travel through rocks?
Primary body waves: (P-wave) compresses material in direction of propagation Fastest wave Secondary body waves: (S-wave) shears material up and down, perpendicular to propagation 2nd fastest wave Does not travel through liquid
What is the law of uniformitarianism?
Processes at work today, are the same as how they worked in the past The present is the KEY to the past
How can we mitigate earthquake damage?
Produce/use hazard maps, improve building design, earthquake resistant building, helps absorb surface movement
Be able to identify examples of quantitative and qualitative data.
Qualitative date: descriptions typically conveyed with words, sketches, images Quantitative date: numeric measurements collected in the field or in a lab
Know how to count the number of times magnetic polarity changes if given a figure of magnetic patterns on the seafloor
Rate of spreading for stripe = width of stripe/ time duration
What are the two types of surface waves and how do they travel through rocks?
Rayleigh waves: vertical surface wave compresses materials Love waves: horizontal surface wave shears material
What are regressions and transgressions in terms of sea level? How do geologists determine a regression or transgress occurred in the rock record of a stratigraphic section?
Regressions and transgressions are changes in sea level that result in either the exposure or flooding of continental or marine environments. A regression occurs when the sea level falls, resulting in the exposure of the land that was once submerged. A transgression, on the other hand, occurs when the sea level rises and floods the previously exposed land. Geologists can determine whether a regression or transgression has occurred by examining the sedimentary rocks and the fossils they contain. For example, if a rock sequence contains marine fossils such as mollusks, it suggests that the environment was once submerged in water, indicating a transgression. In contrast, if the rock sequence contains terrestrial plant fossils, it suggests that the environment was once exposed, indicating a regression. The presence of sedimentary structures such as cross-bedding and ripple marks can also provide clues to the depositional environment and help determine whether a regression or transgression occurred.
What is the difference between relative dating and numeric dating?
Relative dating is putting events in order (oldest to youngest) based on their relative position Law of superposition - layers of rock are oldest at the bottom and youngest at the top Cross-cutting relationships - youngest features cut older features Law of included fragments - younger rocks or deposits can include older pieces of rock Contact effect - a younger magma can bake or alter older rocks that it encounters Numerical dating is the use of radioisotopes in rocks and other materials to provide an age of rock formation or deposition, when geologic events occurred Numeric ages provide age constraints
What is a fossil?
Remains of past organisms that have been preserved in a rock or sediment
What type of fault boundary is most likely to form a tsunami and why?
Reverse faults
What are some ways geology helps to explain our world?
Rocks can include fossils that provide evidence of ancient life and past climates. Geology tells us a story. The color, the position, and the shape of rocks can tell us what type of rock it is, we can age rocks and we can even age fossils in rocks.
Can earthquakes be predicted?
Scientists cannot predict when an earthquake will happen, but a forecast is possible. Scientist can calculate the probability that a significant earthquake will occur in a specific area within a certain number of years.
What are sediment and sedimentary rocks important?
Sediment and sedimentary rocks are important because they provide a record of Earth's history, including past environments, climates, and life forms. By studying sedimentary rocks, geologists can reconstruct the geologic history of an area and gain insight into the processes that shaped the Earth over millions of years. Sedimentary rocks are also important for their economic value, as they often contain valuable resources such as oil, gas, coal, and minerals. Additionally, sedimentary rocks serve as a reservoir for groundwater and provide habitats for a variety of organisms.
What can precede (provide indication of) a volcanic eruption?
Seismic activity increases with impending eruptions from magma flowing through crust Increased gas activity as magma rises to the surface Change sin topography: surveying equipment measures ground deformation Changes in temperature: measured by ground instruments or satelite imagery
How do seismic waves behave as they travel through different material?
Seismic wave radiates in all directions At a boundary, wave will reflect or refract From faster to slower material: steeper angle From slower to faster material: shallower angle Rising wave from faster to slower A seismic wave bends as it travels through crust and mantle Rocks get denser deeper in earth Curved paths permit us to find depth to crust-mantle boundary
How can we use seismic waves to find the epicenter of an earthquake?
Select 3 seismic station records and find P and S wave arrival times to determine the time between Determine distance of epicenter to each station Triangulate epicenter location
What are the different types of maps geologist use and what information do each provide?
Shaded relief map Shows the shape of the land using simulated sunlight generating light and dark shading on hills and valleys Digital elevation models Topographic map with elevation counters - lines of equal elevation Give no specific information about geology Contour lines are more closely spaced where the land surface is steep Satelite images Computer generated image based on different light wavelengths reflected from the surface Shows distributions of surface materials and features, like different types of rocks or vegetation False-color image Geologic maps Created by geologists from observations and collected data Shows types and ages of rocks and features
What is Continental Drift and what evidence was proposed to explain the concept?
Shifting/movement of continents across earths surface through time; oceans were stable with continents drifting on top In 1912 proposed earths continents have moved to their present positions after fragmentation of a large landmass in the geologic past: Pangea Evidence: Jig saw puzzle like match Similar geology Observation of terrestrial fossils found on continents now separated by oceans Evidence of glaciers around the equator and glacial features indicates glaciers coming from directions that are now oceans
What are silicate minerals? And how are the sub-classes of silicates classified?
Silicate minerals are the most important rock-forming minerals because they comprise most of Earth's crust and mantle. They are classified based on the way in which the tetrahedral units are linked together
For siliciclastic sedimentary rocks: how are they classified and which sediment form which sedimentary rock: for example sands form into sandstone
Siliciclastic sedimentary rocks are classified based on the grain size of the sediment particles that make them up. The most common siliciclastic sedimentary rocks are: 1. Conglomerate: This rock is made up of large, rounded particles (gravel-sized) that are cemented together. Conglomerate is formed from the erosion and transport of rocks in high-energy environments such as rivers and beaches. 2. Sandstone: This rock is made up of sand-sized particles that are cemented together. Sandstone is formed in environments such as beaches, riverbanks, and sand dunes. 3. Siltstone: This rock is made up of silt-sized particles that are cemented together. Siltstone is formed in environments such as river floodplains, lake bottoms, and deltas. 4. Shale: This rock is made up of clay-sized particles that are compacted and cemented together. Shale is formed in low-energy environments such as quiet lakes and deep ocean basins. In general, sand particles form sandstone, silt particles form siltstone, and clay particles form shale. However, in reality, sedimentary rocks can be composed of a mixture of particle sizes, and the specific type of rock that forms depends on the conditions of deposition and subsequent diagenesis (the physical and chemical changes that occur during lithification).
What are the mechanisms of plate tectonics?
Slab pull - subduction dense oceanic crust, gravity pulls the slab down in to asthenosphere Ridge push- gravity causes plates to slide away from topography of mid ocean ridges, pushing plate outward Mantle convection - hotter material rises and cooler material sinks - drag force along base of plates
How does a block diagram, a cross section, and a stratigraphic column portray the geology? What are their differences?
Stratigraphic column: illustrates a sequence of stacked rocks or sediment layers in 1D Vertical: thickness Symbols/colors: types of rocks Horizontal: relative resistance to weathering and erosion Cross section: a 2D representation of the subsurface geology A slice of the subsurface Illustrating a topographic profile, and the rock layers and geologic features like faults Block diagrams: illustrate the shape of the surface and subsurface features like rock layers, forming canyon
How do ocean currents affect Temperature and precipitation on land?
Surface currents are driven by wind patterns Helps distribute the uneven heating of sea surface waters by the sun; moving warmer waters poleward and colder waters to lower latitudes Currents flowing away from tropics bring warm water Currents flowing away from poles bring colder water East-west currents can be warm or cold Currents combine in circular flow pattern The gulf stream brings water heated from the tropics to the north Atlantic helping warm the region The pacific equatorial counter current flows east, can weaken or strengthen changing weather conditions Affects life in seas and weather on land
Ground motion from seismic waves can cause what sort of hazards?
Surface ruptures, landslides, structural damage such as bridge failure and aftershocks.
Know the causes and differences between the Great Dying and the K-T extinction events
The Great Dying -252 MA Deadliest mass extinct 96% of all life perished Long recover Put massive amounts of CO in the atmosphere Sea lev el dropped Meteorite impact K-T extinction Mass extinction of the Dinos 70% of all species on the planet became extinct Other animals adapted to these changing conditions A large asteroid impact and a giant volcanic eruption
What are the two main contributors to sea level rise as climate warms?
The added water from melting ice sheets and glaciers and the expansion of seawater is warm
How does geology influence the distribution of resources? Examples?
The age of rocks and how the rocks are formed are two of many geologic factors that control where mineral resources occur. Resources are often not in places where humans would prefer them to be. Large iron mines are common in the Great Lakes region. Large copper mines are restricted to mountain zones.
What is the Cambrian explosion?
The boundary between the end of the Precambrian eon and start of Phanerozoic eon Refers to the sudden appearance of complex marine animals with mineralized skeletal remains (hard parts) in the fossil record Cambrian seas produced representatives of many marine groups
What is the Brittle vs ductile zone and how does Crustal Rock strength with depth relate?
The brittle zone is the shallow levels where rocks fracture and fault. In the brittle zone, stress causes rocks to fracture. The ductile zone is the deeper levels where rock flows.
What is the difference between Hypocenter, Epicenter, Focus of an earthquake?
The hypocenter/focus is where the earthquake is generated, point of origin Epicenter is the point on earths surface directly above the hypocenter
What does internal atomic arrangement mean?
The internal structure is characterized by periodic or predictable arrays of atoms, ions, or molecules.
What are common processes that can cause magma composition to change/evolve?
The composition of magma can change or evolve due to several processes, including: Assimilation: When magma comes into contact with and incorporates surrounding rock, its composition can change. Fractional crystallization: As magma cools and minerals crystallize out of it, the remaining melt becomes more silica-rich and less mafic. Mixing: When two magmas with different compositions mix together, the resulting magma can have an intermediate composition. Magma differentiation: As magma rises and cools, it can separate into two or more chemically distinct melts with different compositions. These processes can occur in various combinations, leading to a wide range of magma compositions and types of igneous rocks.
What is Plate Tectonics?
The continual motion, creating, and destruction of the Earth's active surface: lithosphere (crust and upper mantle)
What is the relationship between elements, minerals, and rocks? (is a rock a mineral?)
The earth's crust is composed of a variety of rocks Rocks are composed of minerals The earth is made of various rocks Rocks are composed of one or more minerals Elements -> minerals -> rocks
What causes the Earth to have seasons?
The earths tilt Earths axis tilted with respect to earths orbit around the sun The axis is fixed in position so direction it points relative to the sun changes during a region
What is the geologic timescale?
The geological timescale is the record of Earth's history based on geological formations and major biological events. It is divided into eras and stretches as far back as Earth has existed. Special Calendar. - Cenozoic: present-66Ma -Mesozoic: 252-66 Ma -Palezoic: 541-252 Ma Precambrian: started at 4,500 Ma
What are some indicators of environment that sediment and sedimentary rocks contain?
The grain size, sorting, and clast shape in sedimentary rocks can provide clues about the environment where the sediment was deposited. In addition, features like cross-bedding, ripple marks, and mud cracks can indicate whether the sediment was deposited in a marine or terrestrial setting, a river or delta, a desert or beach, or a lake or swamp. Fossils within sedimentary rocks can also provide information about the environment in which they formed, such as the presence of marine organisms indicating a marine environment or plant fossils indicating a terrestrial environment.
Difference between confining pressure and differential stress
The high confining pressure pushes inward and generally is greater than any forces pulling the rock apart, but differential stress can act like tension, stretching the rock.
What is the Keeling Curve and its significance?
The keeling curve is a graph that represents the concentration of carbon dioxide in earths atmosphere since 1958. It shows the atmospheric CO2 levels increasing at a faster rate each year... because of fossil fuels
How do seismic waves from earthquakes indicate the depth of boundary layers in the Earth?
The p-wave velocity increases or decreases at certain depths inside the earth. Curved paths permit us to find depth to crust-mantle boundary
what does the presence of larger clasts indicate about the energy of the environment and transport distance?
The presence of larger clasts in sedimentary rocks indicates that the environment had higher energy, such as fast-moving water or wind, which could transport larger particles. Larger clasts can also indicate that the sediment was transported over a shorter distance because smaller particles tend to be deposited first before larger particles settle out.
What are subdivisions/major boundaries of the geologic time scale based on?
The records presented in rocks They placed earths rock layers in order by relative age
What is the rock cycle?
The rock cycle does not occur in a specific order nor does each rock go through the entire cycle. There are many things that can happen to a rock after it forms. Weathering is when a rock on their surface interacts with sunlight, rain, wind, plants, animals etc. As a result, it may be broken apart into pieces or altered by chemical reactions. Weathering creates sediment. Rock pieces loosened by weathering can be stripped away by erosion and moved away from their source. Glaciers, flowing water, wind, and gravity can transport this eroded material away. When the energy of transportation decreases, water, wind and ice deposit their sediments. Once deposited, sediment can be buried and compacted by the weight of over material. Chemicals in groundwater can coat sedimentary grains with minerals. The process of sediment turning into rock is lithification. A rock exposed to high temperatures may melt to produce a mass of magma which usually occurs at a great depth. As magma cools, it will solidify, a process called solidification. If Crystals form during solidification, the process is called crystallization. At any point during a rocks history, a rock may be uplifted back to the surface where it is again exposed to weathering.
What is the order of the sedimentary rock process part of the rock cycle: from weathering to lithification
The sedimentary rock process part of the rock cycle can be summarized as follows: 1. Weathering: The process by which rocks are broken down into smaller particles due to exposure to physical, chemical, and biological processes. 2. Erosion: The process by which weathered rock fragments are transported away from their original location by water, wind, or ice. 3. Deposition: The settling of eroded rock fragments or sediments on the Earth's surface due to the loss of energy of the transport agent. 4. Compaction: The process by which the weight of overlying sediments compresses the underlying sediments, reducing pore space and causing the grains to become more tightly packed. 5. Cementation: The precipitation of minerals from groundwater, which fills in the spaces between the sediment grains and glues them together. 6. Lithification: The process by which loose sediment is transformed into solid rock through compaction and cementation. The end result is a sedimentary rock, which is formed from the accumulation and consolidation of sediment.
What are the Milankovitch cycles? How do they influence Earth's climate?
The shape of earths orbit, known as eccentricity. The angle earths axis is tilted with respect to earths orbital plane. Periodic changes in the orbital characteristics of a planet that control how much sunlight it receives this affecting its climate
What does grain size, sorting, and clast shape indicate about the sedimentary environment that sediment was deposited in?
The size, shape, and sorting of sedimentary grains can tell us about the environment in which they were deposited. Larger grains usually indicate a high-energy environment such as a river or beach, while smaller grains may suggest a low-energy environment like a lake or deep ocean. Well-sorted grains suggest that they were transported by a uniform energy source such as wind or waves, while poorly sorted grains suggest a mixture of energy sources. Clast shape can also provide clues about the distance and duration of sediment transport.
What is faunal succession?
The systematic change of fossils with age Fossils occur in strata in a definite, determinable order Once an organism goes extinct, it does not come back
Were would you expect the continental crust to be thickest or the thinnest?
The thickness of the continental crust ranges from less than 16 miles to more than 37 miles. Regions with high elevations tend to have thicker crust. So an area with the thinnest crust would have to be an area with low elevation.
Difference between the three classifications of sedimentary rocks (how are they formed), be able to provide examples of sedimentary rocks for each
The three classifications of sedimentary rocks are clastic, chemical, and organic. Clastic sedimentary rocks are formed from the accumulation and cementation of rock and mineral fragments, known as clasts, that are produced by weathering and erosion of pre-existing rocks. Examples of clastic sedimentary rocks include sandstone, shale, and conglomerate. Chemical sedimentary rocks form from the precipitation of minerals from water, often due to evaporation. Examples of chemical sedimentary rocks include limestone, halite, and chert. Organic sedimentary rocks are made up of the remains of once-living organisms such as plants or animals. Examples of organic sedimentary rocks include coal, oil shale, and some types of limestone.
How are rocks classified? And what are the three major categories? (hydrothermal is the fourth)
The three main categories of rocks are: Igneous Solidification of magma and lava Metamorphic Preexisting rock changed due to increases in temperature and pressure Sedimentary Deposit of sediments Formed through weathering or breaking down of previous rocks
What are the different types of volcanoes? (there are four that have vents, and two that have no central vents)
There are four types of volcanoes that have vents: Shield volcanoes: broad, gently sloping, and have runny lava flows Stratovolcanoes: steep-sided, cone-shaped, and have explosive eruptions Cinder cones: small, steep-sided, and composed of loose volcanic fragments Complex volcanoes: a combination of different types of volcanoes There are two types of volcanoes that have no central vents: Fissure volcanoes: long cracks in the Earth's surface that emit lava Submarine volcanoes: located on the ocean floor
Why are silicate minerals the most common rock forming mineral?
They are the most common because contain silicon and oxygen, which are the two most abundant elements in the crust
What is the distribution of volcanism and earthquakes related to plate tectonics?
They tend to occur along limited zones or belts. With the understanding of plate tectonics, scientists recognized that these belts occur along plate boundaries.
What is porphyritic texture? And what does it indicate about the cooling rate?
This texture describes a rock that has well-formed crystals visible to the naked eye. Its developed when magma that has been slowly cooling and crystalizing within the earths crust is suddenly erupted at the surface, causing the remaining uncrystallized magma to cool rapidly.
What does it mean when geologists apply trading location for time?
Trading location for time is envisioning long-term landscape change Geologists use distinct parts of the landscape that represent various stages of the landscapes evolution Erosion by water and other process starts cutting down into plateau and eroding its side
Know the differences between a divergent, convergent, and transform plate boundary?
Transform Boundaries Parts of the lithosphere are sliding past each other horizontally Where plates slide sideways, horizontally, past each other in different directions Faults of transform boundaries are called transform or strike-slip faults Crust is neither created not destroyed, but it can be deformed Transform(strike-slip) faults Occur besides or within a continent Are associated with MOR Divergent Boundaries Plates move away from each other. Two plates with ocean crust. Mid ocean ridges (seafloor spreading centers) Two plates with continental crust: continental rifting Divergent boundary at mid-ocean ridges Two lithospheric plates with ocean crusts Where plates move away from each other Crust is experiencing extension and thinking New oceanic crust is forming Convergent Boundaries Collide and merge Continental rifting- when continents break apart Subduction zones Two plates with oceanic crust Two plates, continental and oceanic crust Continental Collision Two plates with continental crust Where plates move towards each other Crust experiences shortening and thickening Crust is deformed or destroyed then recycled in the mantle Pacific ring of fire Oceanic plates subjected on both sides Convergent boundary with two continents: continental convergence
What influences/controls a mineral crystal's shape?
Unrestrained crystal form mimics the internal atomic structure How the atoms are arranged builds the internal structure Internal structure of halite Mineral crystals with flat surfaces and terminations indicate they had room to grow uninhibited. Euhedral: well-developed flat crystal faces with terminations Anhedral: crystals with irregularly shaped masses; share crystal borders in an interlocking pattern
What are vesicles (be able to identify) and what does vesicles in a basalt indicate?
Vesicles are the small holes left behind after lava cools and turns into volcanic rocks. Vesicles help geologists understand the cooling history of extrusive rocks.
How does viscosity and gasses influence eruption style?
Viscosity and gases influence eruption style by affecting how easily magma can flow out of the volcano. High viscosity (thick) magma tends to trap gases, which can cause explosive eruptions, while low viscosity (runny) magma tends to release gas more easily, leading to effusive eruptions. The amount and composition of gases in the magma can also play a role in eruption style. The higher the gas content, the more likely an explosive eruption will occur.
What are some examples of how volcanoes are monitored to help forecast potential eruptions?
Volcanoes are monitored using various techniques such as seismometers to detect earthquakes, GPS to track ground deformation, gas sensors to detect changes in gas emissions, thermal cameras to measure temperature changes, and satellite imagery to monitor changes in topography. By analyzing these data, scientists can forecast potential eruptions and issue warnings to protect people and property in the affected areas.
How does water interact with the geosphere?
Water interacts with earths sphere and they influence one another The hydrologic cycle... the moment of H2O (liquid, solid or gas) Precipitation = weathering Runoff = transports sediments and carves our landscapes Glaciers = care land, produce and transport sediment, influxes ocean water chemistry and sea level
What are some greenhouse gasses and why is CO2 the most concerning for our current climate change?
Water vapor, oxygen, methane, and carbon dioxide.
What is the difference between weather and climate?
Weather is a daily description of the temperature, pressure, and precipitation conditions of the atmosphere for a specific place. Climate is a longer term view of these same factors, typically taken over a period of many years.
What is the rain shadow effect?
When warm, moist air rises against high elevations of land and drops its water along the way.
How does wind form?
Wind is movement of air relative to earths surface. It forms in response to differences in air pressure from place to place and between different heights above the Earth's surface.
How do we know humans/burning of fossil fuels are the cause of the current change in climate?
he change in the ratio of carbon-12 to carbon-13 tells scientists the carbon in the air is more from burning fossil fuels than natural carbon.
What is Bowen's reaction series?
the order in which specific minerals cool and form within melted magma, from hottest to coolest
What is the Greenhouse Effect- how does it work?
the trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface.
