EDT182 exam 1
Briefly describe the following intrusive igneous rock features: a) batholith b) dike c) sill d) stock e) laccolith f) volcanic neck (or pipe)
Batholith: large body of intrusive igneous rocks believed to have been crystalized at the considerable depth below the earth's surface
List some of the landscape features associated with alpine glaciers
Begin high up in the mountain in bowl shaped hollows called cirques
Biosphere
Biosphere: - The biosphere of earth includes all living things on planet Earth like animals, plants and microorganisms. Most of this life exists no deeper than about 10 feet into the ground or approximately 600 feet above it. There are different ecological communities divided in six main biomes which are desert, aquatic, forest, grassland, tundra and chaparral. It is the biggest one of all four spheres of earth.
What are the three basic origins of mountains?
Block mountains, volcanic, fold
Name and describe the two classifications of sedimentary rocks.
Clastic: mechanical weathering debris Chemical: dissolved materials precipitate from solution Organic: Accumulation of plant or animal debris
Colliding plates
Colliding plates Where plates come into contact, energy is released. Plates sliding past each other cause friction and heat. Subducting plates melt into the mantle, and diverging plates create new crust material. Subducting plates, where one tectonic plate is being driven under another, are associated with volcanoes and earthquakes. This activity is focused along the edge of the plate boundary where two plates come into contact, forming regions such as the Pacific Ring of Fire - a chain of earthquake and volcanic activity around the edge of the Pacific Ocean - which generates 75% of the world's volcanoes and 80% of the world's earthquakes.
What are the defining characteristics/properties of minerals?
Color, hardness, cleavage, magnetism, odor, taste, hardness and streak
Groundwater is removed from the ground via wells. Describe what a cone of depression is and how it is created.
Cone depression: occurs in an acquirer when groundwater is pumped from a well - slowly due to gravity drains a large amount of water from the sediment within the increasing cone
The layers of the earth
Crust Mantle Outer Core Inner Core Lithosphere The lithosphere is the outermost layer of the Earth ~100 km thick and is defined by its mechanical properties. This rigid layer includes the brittle upper portion of the mantle and the crust. The lithosphere is divided into 15 major tectonic plates, and it is at the boundary of these plates where major tectonic occurs, such as earthquakes and volcanoes. The lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. The lithosphere is the coolest layer of the Earth in terms of temperature, with the heat from the lower layers generating the plate movements. The term "lithosphere" should not be confused with the use of "geosphere," which is used to indicate all of Earth's systems, including the atmosphere, hydrosphere, and biosphere. Asthenosphere The asthenosphere includes the upper part of the mantle that is highly viscous and mechanically weak. The lithosphere-asthenosphere boundary (LAB) is where geophysicists mark the difference in ductility (a measures a solid material's ability to deform or stretch under stress) between the two layers. This boundary in the upper mantle is marked at the 1300oC isotherm. Above the isotherm marks where the mantle behaves in a rigid fashion and below which it behaves in a ductile fashion. It is the ductile rocks in the upper part of the asthenosphere that are believed to be in the zone upon which the great rigid and brittle lithospheric plates of the Earth's crust move about. Seismic waves travel relatively slowly through the asthenosphere. Mesosphere The mesosphere refers to the mantle in the region under the lithosphere and the asthenosphere, but above the outer core. The upper boundary is defined as the sharp increase in seismic wave velocities and density at a depth of 660 kilometers (410 mi). This layer should not be confused with the atmospheric mesosphere.
Diverging plates
Diverging plates When plates move away from each other, the space between them gets filled with material, which rises to the surface, cools and forms mid-oceanic ridges. The Pacific Ocean is growing wider by about 18 cm per year as the plates diverge and the mid-oceanic ridge is built up.
Triangulation
Drawing circles around cities to determine where an earthquake is at
What is the theory of plate tectonics?
Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core.
What is the a) fault plane b) footwall c) hanging wall?
Fault plane: plane/ surface formed between the two rock blocks that slip one with he other during an earthquake
How does a glacier form and move?
Glaciers form from crystalized snow AS more snow falls the pressure exerted on the bottom layers of the icy snow compacts and recryalizes into glacier ice Plastic flow of the slipping ice crystals Basal sliding- when melted ice forms at the base of the glacier
Explain how the composition of the magma affects the type of volcanic eruption that occurs
High silica magmas are higher in viscosity and produce violent eruption. Basaltic magmas are much less viscous and tend to flow when erupted, not explode
Describe the different types of chemical weathering.
Hydration:caused by water, alters the size and composition of the mineral Carbonation: water and carbon dioxide equal canonic acid, rock mineral react with weak carbonic acid Oxidation: rusting, rock minerals lost one or more ion or atoms in the presence of oxygen
Hydrosphere
Hydrosphere: - The hydrosphere contains all the solid, liquid and gaseous water of the planet. Approximately 97% of the earth's water is salty and only a small portion (about 3%) is non-salty. The saltwater gets collected along the earth's surface in deep valleys. This sphere ranges from 10 to 20 kilometers in thickness. It stretches all the way from the earth's surface down numerous miles into the lithosphere and high above the crust into the atmosphere.
What is the rock cycle? Why is the rock cycle unique to planet Earth?
It effects other cycles Look up how to draw it
Name, in order from oldest to youngest, the four glacial episodes that occurred in North America during the last ice age
Kasan, Nebraskan, Illionian, Wisconsin Named for the states representing the furthest advance where deposits are exposed
What is land subsidence? Give an example of where this has occurred or is still occurring.
Land subsidence: gradual setting or sudden sinking of the Earth's surface owing to subsurface movement of Earth minerals Ex: South Central Arizona
Geosphere/Lithosphere
Lithosphere: - The lithosphere can be defined as the outer boundary layer of solid earth and discontinuity within the mantle. It is a crustal system composed of various layers which are core, mantle and outer crust. It is also known as geosphere. The actual thickness of this sphere varies considerably and can range from roughly 40 kilometer to 280 kilometer.
What evidence was used to support and prove the concept of continental drift and seafloor spreading?
Mantle oozes upwards, new lithosphere formed, molten mineral, magnetic stripes and drilling samples
S and P waves
P is when it starts and S is when it jumps up S-P = lag time Amplitude is how tall the first big wave is Magnitude is on a richter scale
Describe some of the prominent organisms and events found within each of the eras and periods.
Paleozoic: Silurian Prominent organisms: rich shallow ecosystems, marine life, coral reefs, plants Events: extensive continental regions were flooded with water ranging from a few ft to 330 ft Mesozoic: Jurassic Organisms: Reptiles, Stegosaurus, Sauropods, Brachiosaurs Events: The supercontinent Pangea split apart into two land masses in the north Laurasia and in the south Gondwana. Precede by mass extinction Cenozoic: tertiary Organisms: Insects, birds, bees, mammals Events: dramatic expansion of mammals, plants, insects and more. Vast stretches of oceans were created impacting marine life
Describe how seismic waves were used to discover the boundaries of the Earth's interior.
Provided evidence of internal layering
Describe radiometric dating, radioactive decay, and half-life.
Radiometric dating: is a technique used to date materials such as rock or carbon usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products- decay rates Radioactive decay: by which the nucleus loses energy by emitting radiation Half Life: time required for a quantity to reduce half of its initial value
Describe the different forms of mass movement (mass wasting).
Rockfall and rockslides Rockfall- occurs when pieces of rock break loose from a step cliff Rockslide- follow a zone of weakness Debris flow- turbulence occurs throughout the mass earthflow, mudflow, avalanche Creep- gradual movement of soil Slump- material moved
Briefly describe erosion by running water and the associated landforms.
Running water have two component- one is overland flow on the general land surface as a sheer Other is the linear flow as streams and rivers in valleys
Compare and contrast sand dunes and loess
Sand dunes: begin to form where airflow is blocked by an obstacle, such as a rock or a dump or vegetation Both are wing blown deposits. Loess is made of silt Dunes are made of sand
Describe how the location of an earthquake is identified by a seismic recording station.
Seismologists use the difference in arrival time between the p and the s waves to calculate the distance between the earthquake source and the recording source
What is a tsunami and what causes them?
Series of waves in a body of water caused by the displacement of a large volume of water
What are the two main groups of minerals? How are they sub-divided?
Silicates and non-silicates Silicates are those that contain iron or magnesium (ferromagnesian) those that don't (nonferromagnesium) Non-silicates are carbonates, sulfates, halides, oxides, sulfides , phosphates and native elements ex: gold and silver
Name and describe the two types of metamorphic rock.
Slate: is the lowest grade foliated metamorphic rock, which means that it is formed under relatively low temperature and pressure Schist: is on of the most recognizable metamorphic rocks because it is scaly looking with large micas that reflect light like tinted windows
Define soil and describe the four different horizons.
Soil:mixture of organic matter, minerals gases, liquids and organisms living together Soil horizon: distinct layers of the soil lying one above the other, parallel to the soil surface O:: organic, implies it is rich in humus the organic matter of the plant and animal origin A (topsoil): topmost layer of the mineral soil, darker than the layer below E: light color, sand and silt content, poor in mineral B(subsoil): Rich in clay and mineral like iron and aluminum C: mainly made of large rock or lumps particularly broken bedrock R(Bedrock):deepest soil horizon, continuous mass of bedrock
Compare and contrast the three main types of volcanoes.
Stratovolcanoes / composite- layers of solid lava flows mixed with layers of other rock Cinder cone- No horizontal layers and is a steep conical hill of tephra (volcanic debris) that accumulates around and downward from the vent Shield- build entirely/ mostly of fluid lave vents when viewed from above you can see how massive they are
What is stress (in geologic terms) and strain? What are the different types and how do they differ?
Stress: the force applied to an object Confining stress- deeply buried rock that can not move Strain: forces are parallel but moving in opposite directions
Subducting Plates
Subducting plates and volcanoes Plate material that is produced along the ocean floor is generally quite dense and relatively heavy. Continental plates don't tend to get subducted. When oceanic plate is pushed from the mid-ocean ridge towards a plate boundary with a continental plate, it tends to subduct or dive below the continental crust. In this process, water is also being subducted with the oceanic plate. Friction increases the heat along such boundaries, which causes this material to melt and mix the oceanic plate material, the continental plate material and the water. Andesite volcanoes tend to form at these subduction boundaries. This may have something to do with differences in plate densities and the release of gases, such as water vapour. As more heat is being produced through the subduction process, the mix of more and less volatile ingredients causes changes in density and pressure, which are linked to volcanic activity.
Describe the difference between an anticline and a syncline and how you can determine the difference.
Syncline fold in a V shape and Anticline fold in an A shape V shape arches dip away A shape limps dip toward hinge
Explain why the earth has layers by comparing the composition and density of elements in each layer.
The Earth's core is mainly iron and small amounts of Nickel Surrounding the core is the mantle, a rocky layer Then the crust, two kinds oceanic and tibetan and they differ in density
What is the Mohorovicic (Moho) discontinunity?
The boundary lying between the crust and the mantle of the earth across which seismic waves change velocity
Describe the composition and structure of a) the core b) the mantle and C) the crust
The core: liquified igneous rock The mantle: composed of rocks containing iron and magnesium The crust: least dense calcium, sodium, aluminum-silicate minerals
Earthquake strength is measured by the Richter scale. Describe this scale and how it relates to the energy released.
The magnitude of an earth quake is measured by a pitcher scale, if there is a high magnitude there is a lot of energy
Describe the different types of mechanical weathering.
Thermal expansion: daily heating and cooling of rock, irrespective of the mount of water present, cause stress along the boundaries of various minerals that compose the rock Frost action: the water as it comes into the fractures and worse of rock freezes Exfoliation: Rock breaks off into leaves or sheets along its joints Organic: plants and animals can weather the rocks by pushing their roots into cracks and void spaces
Name the two types of igneous rock and describe their formation.
Volcanic molten rock- at the Earth's surface when lava cools Plutonic- when molten rock below earth's surface magma cools
Briefly describe the dangers associated with volcanoes, including ashfall, nuee ardente, landslides, lahars, and toxic gases.
Volcanoes have unstable surfaces VOlcanic gases create acidic groundwork lahars are formed by intense rainfall during or after an eruption can easily erode loose volcanic rock Ashfall, hazardous substance carried in ash - carbon dioxide, sulfate Nuee ardente, a deadly pyroclastic flow lave, fragment, ash cloud from volcanoes all pose a threat
What is the water table? How does the height of the water table change and how does the location of the water table create different land features?
Water table: is the surface where the water pressure head is equal to the atmosphere pressure -low when the surface is high and high when the surface is low
Describe the four stages that produce sedimentary rocks - weathering, erosion, deposition, and sedimentation/lithification.
Weathering: when rocks are exposed to elements, causing break down
Describe the basic process of a volcanic eruption.
When a volcano erupts, it sends out a ash cloud, lava and volcanic bombs Volcanic gases, lave and flow of sand
Describe the characteristic features associated with stream erosion as the stream valley evolves
Youth: rapid downcutting, streams with straight channels and steep gradients, deep v shaped alluvial valleys Maturity: the start of lateral erosion an valley widening, alluvial valleys with moderately sloping walls and wide floor plains Old age: extensive lateral erosion and little downcutting, alluvial valley with gently sloping walls and a broad low relief valley floor
What is an earthquake?
a sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action.
Explain the distribution of water on Earth.
because water is much denser than any gases this means that water will flow into formed depressions
Describe the water cycle.
continuous movement of water on, above, and below Earth's surface
define sedimentation/lithifaction
end product of erosion when it becomes sediment ex: sand, mud, clay
define sill
formed when a sheet of magma lies alms the bedding planes of the earth's surface
Four Spheres of Earth
geosphere/lithosphere, atmosphere, hydrosphere, biosphere
List some of the landscape features associated with continental glaciers
ice sheet larger than alpine
What are the requirements for an index fossil?
must be widespread, commonly found (sometimes in groups) and short life span
Infiltration
process by which water on ground surface enters soil
define dike
sheet of rock that is formed in the fracture in the pre-extisting rock
Define footwall
the block of rock below a fault
Define hanging wall
the block of rock that lies above an inclined flat or ore body- compared to foot wall
define deposition
the dropping of sediment in a new place ex: formation of an island, sand dunes
define erosion
the movement of sediment from broken rock ex: water, ice, wind , gravity
define laccolith
this is a sheet of intrusion that has been injected two layers of sedimentary rock
What is an unconformity? An angular unconformity?
unconformity- represents time during which no sediments were preserved in a region is a buried erosional or non depositional surface that separates two different age rock masses or strata angular unconformity- type of community in which younger flat rock were deposited over older tilted eroded rock layers
Describe the three types of plate boundaries and the geologic features and activity associated with each type (such as earthquakes, volcanoes, etc).
- two tectonic plates collide: convergent plate boundary - one converging plate under another: subduction - tectonic plates are being subjected: deep trenches
Describe the three classifications of faults.
1. Normal fault- the hanging wall/ upper side of the fault drops down. The forces involved moves sides upward 2. Reverse fallout- the opposite happens, the hanging wall moves in and upward direction the force pushes sides together 3. The strike- slip faults, the walls move from side to side instead of up and down direction (no hanging walls exist)
What are the two main conditions usually required for fossilization?
1. Rapid burial 2. Hard body parts
Compare and contrast the different types of seismic waves.
3 types; primary, secondary and surface primary and second are known as body waves and penetrate the interior of the earth. Surface waves do not penetrate the earth
What are the two major processes of wind erosion?
Abrasion and deflation Deflation is further broken down into 3 categories; surface creep, saltation and suspension. The wind carries tiny particles along with it when it blows. When the wind blow against solid objects, those particles strike the objects.
What is the difference between absolute dating and relative dating?
Absolute dating: also called numerical dating arranges historical remains in order of their ages Relative dating: arranges then in geological order of their formation - very effective when it come to radio active isotope or radio carbon dating
Who proposed the concept of continental drift and the supercontinent Pangaea and what was some of the evidence that was used to create this hypothesis?
Alfred Wegener 1912 Land features, fossils and climate
Describe how metamorphic rocks form.
Alteration of pre-existing rocks from exposure to heat and pressure while remaining in a solid form
What are hot spots? Name at least one place where a hot spot is located.
Ares of volcanic activity within the interior of a lithosphere plate associated with magma rising up from the mantle below ex: hawaiian island
Name and describe features that are created as a result of carbonate dissolution.
As groundwater steadily dissolves the limestone, it creates unusual erosional features such as; sinkholes and holes
Describe the formation of minerals from magma and water solutions.
As magma cools, atoms in the hot liquid will loose their kinetic energy-they slow down. Attractive forces between those atoms can pull them into orderly crystalize structure.
Atmosphere
Atmosphere: - The atmosphere is a complex fluid system of gases and suspended particles. This fluid system forms a gaseous envelope around the earth with no defined boundaries. The total volume of atmosphere is made up of gases like nitrogen, argon, oxygen, carbon dioxide and water vapour etc.
Briefly describe the following basic geologic principles used to interpret geologic time Principle of uniformity Principle of original horizontality Principle of superposition Principle of crosscutting relationships Principle of Inclusions Principle of lateral continuity Principle of faunal succession
a) Principle of uniformity: using past event to explain what has happened ex: a volcano explosion many yrs ago leaving ash b) Organic horizontality: layers of sediment are deposited horizontally, layers that are tilted/ folded must have been moved into position by disturbance ex: earth and mountain building after deposition c) Superposition: In an undeformed (horizontal) sequence of sedimentary rocks, each layer is older than the one above and younger than the one below Like newspapers in a recycling bin, older papers are found on the bottom d) Cutting Cross Relationships: An igneous intrusion or fault that cuts through pre-extisting rock, is younger than the rock through which it cuts through e) Inclusions: Are the pieces of one rock contained within another. Any inclusion is older than the rock containing it. just as some pieces of rock incorporated in a slab of concrete were formed before the concrete was formed f) Lateral Continuity: sedimentary layers are deposited in all direction over a large area unless some sort of obstruction or barrier limits their deposition. Faulting, folding and erosion can separate originally continuous layers into isolated outcrops g)faunal succession: fossil organisms follow are another in a definite, irreversible time sequence. Fossil communities change through time as species become extinct and new ones appear. Such changes are reflected in the rock record. In this way, fossils provide a key tool for recognizing the relative age of the rock
Describe the 3 main types of fossil preservation listed and provide examples of the types of preservation from each of the three main types. Preservation of all or part of the organism Preservation of an organism's shape Trace Fossils
a) without alteration or direct preservation. the most common directly preserved fossils are unaltered hard parts of living organisms- shells, teeth and bones b) mold and cast is very common. indirect preservation. After remains of an organism have been buried and cemented with sediment, water percolating through the sediment leaches out the fossil C) gives patontogist some evidence of an organism behavior- tracking how dinos moved