Geology, Exam 1 study guide
What are the three primary groupings of rock?
Igneous, sedimentary, and metamorphic
What does vertical exaggeration in Google Earth do?
dramatizes the elevations so we can see the dips/mountains and such better
What are native elements?
minerals composed of a single element examples: gold, silver, and copper
relative amount of silica in felsic rocks
more than 65% silica and lots of sodium, potassium, and alumnium, but LITTLE calcium, iron, magnesium (lighter)
standard reference thickness of oceanic and continental crust
oceanic crust is thinner and denser than continental crust. oceanic= 3-10 km continental= 20-90 km
What type of rock fracturing is common from cooling and contraction of lava and magma at shallow depths?
polygonal fractures/cooling fractures
uniformitarianism
present day processes have operated throughout geologic time; it provides us with the basis for interpreting the past and predicting possible future events
What is the rock cycle?
sedimentary-> metamorphic-> igneous-> sedimentary
What and where are the terrestrial planets in our solar system?
Mercury, Venus, Earth, and Mars They are the first four planets closest to the sun
geometry of dikes and sills with respect to intruded bedrock
sills- inject along pre-existing layering (horizontal) dikes: cut across pre-existing layering (up and down)
What is pegmatite and how does it form?
special type of felsic, very coarse-grained plutonic rock that is commonly developed at the end stages of magma crystallization felsic rock & course-grain rock (select both on test)
What is isostasy?
the theoretical concept of Earth's crust "floating" on a denser underlying layer. Although both the crust and mantle are solid, the crust is less dense and it is buoyed up by the mantle(which because it is under great pressure and high temperature, behaves much like a fluid).
What is the Wilson Cycle in respect to the theory of supercontinents and ocean basins?
-supercontinents like Pangea form, break up, and reform in a cycle spanning 500 million years -The breakup forms rift valleys within the supercontinent that eventually becomes a long, linear sea as the crust is depressed below sea level -As the width of the narrow sea continues to expand an open ocean develops For some reason, rifting and drifting reverses motion, the ocean basins closes, continents collide and are eroded, and the new cycle begins
What are the typical drift rates of tectonic plates?
1 mm to 79 mm per year horizonal velocity, average 26 mm/yr
what are three probable mechanisms that drive plate tectonics?
1) thermal convection cells act as a conveyor belt, carrying the crust along. 2) gravity- effects of ridge push and slab pull 3) meteorite or directed push from hypervelocity of bolide impacts
What are two common names for the light and dark-colored silica rocks having sheeted crystalline structure?
ferromagnesian and nonferromagnesian
What are ferromagnesian minerals?
ferromagnesian silicate contain iron and/or magnesium and tend to be dark and more dense
radicals
groups of tightly bonded elements that behave as a single entity, like silica tetrahedra- have a residual charge
What is mineral cleavage?
having or lacking internal planes of relative structure, including the flat surfaces called faces or facets
What is hypsography with respect to topography?
hypsography is a subsection of topography. hypsography- concerns the land's elevation, altitude or height above sea-level or some other reference surface. typography- concerns physical and cultural features of the land
intrusive-plutonic
igneous rock that cool below the earth's surface
extrusive-volcanic
igneous rock that cools above the earth's surface
plutonic igneous rock names
periodotite; gabbro; diorite; granodiorite; granite
What does the melting of crystal rocks produce?
silica-rich magmas
relative amount of silica in mafic rocks
45-52% silicia, and MORE calcium, iron, and magnesium (darker)
What is retrograde planetary motion and what theory did that help explain?
that mars does another loop because of the gravitational pull, and it helped explain the heliocentric solar system model
What are the 3 principle types of chemical bonding, and how do they differ?
-ionic: electrons transferred -covalent: share pairs of electrons - metallic: sheets; attraction of positively charged metal ions for mobile electrons
Who introduced the heliocentric view and when?
Copernicus in the mid 1500s
What is the difference between crystalline solids and crystals?
Crystalline solids have an orderly atomic structure arranged in a 3-dimensional framework Crystals are crystalline solids with geometric shapes, including planar faces (crystal face), sharp corners, and straight edges
What are the five most common groups of silicate rock forming minerals?
Five Queens Make Apple Pie Feldspar, Quartz, Mica, Amphiboles, Pyroxenes
Palisades Sill- type of rock and location
Type: Palisades diabase- an igneous rock, consists mostly of light feldspar and dark augite location: across the GW bridge NJ-NY/Hudson River
scientific method
Use observation, experiment, and calculation in a series of steps: identify the problem, collect data to form a hypothesis, propose hypothesis, test hypothesis, alter hypothesis to answer questions
why did it take so long for plate tectonics to be accepted by the scientific community?
Wegener could not provide a convincing mechanism to demonstrate how the continents could have moved
Where are active volcanoes located and why?
Where: Along convergent plate boundaries, divergent plate boundaries, and hot spots (Ring of Fire). Why: Magma rises from the underlying mantle when plates pull away, volcanoes are created on overriding plate as melt from the subducting plate rises up through mantle and crust
Why do rare-Earth elements have unique properties?
You have to sift through a lot of soil to find them, and just a small amount of REE can power tech (like a cell phone)
What is the Coriolis effect?
a phenomenon that causes fluids, like water and air, to curve as they travel across or above Earth's surface. Places closer to the equator spin faster west to east than those farther away So, if you tried to throw a paper airplane directly north from Texas (closer to equator), the plane would end up somewhere to right (like Delaware) because it would take a curved path to the right.
What is pyroclastic material and what types of rock does it form?
another name for a cloud of ash, lava fragments carried through the air, and vapor. (ash, lapilli, lava blocks) -it forms igneous rocks
general rock forming process
atom-> element-> mineral-> rock
extrusive/volcanic rock names
basalt; andesite; dacite; rhyolite
What are the relative hardness of calcite, quartz, feldspar, and diamond (Mohs Hardness Scale)?
calcite (3), feldspar (6), quartz (7), diamond (10)
What is the tectonic setting of the west coast of South America?
convergent boundary between South American plate and subducting Nazca plate; 3 inches a yr/ or 77 millimeters
What are the 3 types of tectonic plate boundaries, and give a specific example of each
divergent- occur where plates are separating; example: Oceanic-Mid Atlantic Ridge convergent- when two plates collide, and edge of one plate is subducted by the other; example: Himalayas transform- occur when plates slide laterally past each other
Do wet or dry rocks melt first?
dry
What is the tectonic setting of Japan?
lies at junction of 4 major tectonic plates- Pacific, Philippine Sea, North American (Okhotsk), and Eurasian (Amurian)
How do elements Hydrogen (1) through Iron (26) on the periodic table form?
stellar nucleosynthesis- gravity causes largest nebular cores to become very dense
What is the silicate tetrahedron?
the basic building block of silicates, and is a negatively charged radical (-2)
What are mineral resources and some common examples?
the concentration of materials that are of economic interest in or on the crust of the Earth Examples: gold, gravel, sand, aluminum, copper, limestone, clay, and diamond
What is the basic difference between raster and vector geospatial data?
vector: representation of the world using points, lines, and polygons. raster: representation of the world as a surface divided into a regular grid of cells
Doppler effect
An increase (or decrease) in the frequency of sound, light, or other waves as the source and observer move toward (or away from) each other. A blueshift is any decrease in wavelength, with a corresponding increase in frequency, of an electromagnetic wave; the opposite effect is referred to as redshift.
Why and how are the different silicate mineral groups classified?
Because they contain different ratios of silicon and oxygen
What is the Bowen's reaction series, especially with respect to when mafic and felsic minerals form during the crystallization of magma?
Bowen's reaction series tells the stable temperature and pressure conditions of the different minerals that formed the igneous rock, helps us deduce the possible original melt chemistry that crystallized the rock, allows us to model initial possible conditions and predict outcomes 2 series- discontinous: produces ferromagnesian minerals early on and continuous
