geology rocks Flashcards

Terms Definitions
wire nail
changing into rock.
largest pyroclastic fragments
texture: brittlecolor: colorless, white, yellow, blue, brown, redcleavage: 3 cleavages, intersect at 90 degrees, cubichardness: 2.5
Intrusive igneous environment that does not intrude on any layers
economic mineral, oxide/hyrdoxide, Al oxide and hydroxides: Decsription: earthy, soft, fracture, very light, yellow brown or white streak, pisolitic texture
hard metamorphic rock consisting essentially of interlocking quartz crystals
a surface that:1. represents significant missing time2. and had a sedimentary unit, ash, or lava flow laid down on top of itOR is the current eroded Earth's surface (implies: erosion or period of non-deposition) - river valley that got eroded and now has a new layer of rock on top
Minerals that solidify and only certain temperatures therefore they can tell us at what temperature the rock formed.
economic mineral, native element, Cu: Description: metallic, medium hardness, fracture, heavy, copper streak, oxidizes, odd shape
sediments produced on earth's surface as a result of weathering
sediments transported through process of erosion and become sed. rocks after they come to rest
sedimentary rocks give evidence of ancient sedimentary environments where they are formed
Process that forms sedimentary rocks when layers of sediments are compressed by the weight of the layers above them.
a sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals
strata found truncated (narrowing down towards the surface) originally extended in all directions until they thinned to nothing or reached the edges of their depositional basin
igneous rock
economically important, forms very late in the crystallization of intrusions, very large crystals, forms from high fluid content. because they crystallize last they are enriched with elements that were excluded from typical rock forming silicates, they are right with rare minerals and exotic elements
The process where water or wind loosens and carries away pieces of rock.
sediments being carried by water, ice, wind settles out in layers.
What are mafic rocks?
Dark-colored, low-silica igneous rocks. Most extrusive rocks are mafic.
A chemical compound consisting of a halogen and another element, especially a strongly electropositive metal such as sodium or potassium. ex-salt
metamorphic rocks
result from changes of preexisting rocks, occurs at high temperatures, high pressures, conditions found within Earth
rock in small particles or other material worn or broken away from a mass, as by the action of water or glacial ice.
Red or White Granite
Igneous rock, plutonic, medium-corse grained, felsic (> 65% SiO2), minerology = quartz, orthoclase Na rich plagioclase, biotite, horneblend, muscovite
Rock Cycle
continous changing of rocks from one kind to another over long periods of time.
Metamorphic Rock
Forms when heat, pressure, or fluids act on igneous, sedimentary, or other metamorphic rock to change its form or composition, or both.
•! Many marine organisms have ability to extract ions from seawater and form mineral shells!–! Corals, algae, clams, oysters, and snails! –! Chalk: microscopic carbonate plankton shells, e.g.,forams!•! After organisms die the shells may become incorporated into sedimentary rock.!–! CaCO3 preserved in shallow water whilst SiO2 stable in deep water!
made up of the remains of ancient plants that have been buried and pressed into rock
surface, lava - pouring out of ground to form igneous rocks quickly, or ash solidifying in sky forming igneous glass
fractional crystallization
igneous rocks
the melt changes composition through time because minerals that form early during crystallization differ in composition from the magma and separate from it.
reduction of a solid to a liquid state through use of heat.
What is stratification?
Arrangement in visible layers. Seen in sedimentary rocks.
Streak is..
the color of the residue produced by scratching a mineral on a nonglazed porcelain plate. A mineral may vary in color but the streak is always the same.
a very hard gray or pink rock that is formed when lava cools slowly underground
What are igneous rocks?
Rocks formed by the cooling and hardening of hot molten rock from inside the Earth.
and lithic sandstones
(clastic sedimentary rocks)
quartz sandstone is made completely of quartz
arkose sandstone is at least 25% feldspar
lithic sandstone consists of sand size rock fragments
What is a rock?
A group of minerals bound together in some way.
carbon dioxide and water
sedimentary rocks section
make the most abundant acid in chemical weathering
How do nonfoliated rocks form?
mineral crystals are NOT lined up and the parent rock is made up of 1 mineral; Ex. marble and quartzite
What determines the color of igneous rock?
the level of silica- low levels of silica are DARK in color, like gabbro and basalt-high levels of silica are LIGHT in color like granite and rhyolite
macro, biotite
grains occur randomly.
metamorphic, foliated, quartz, chlorite, muscovite, shows rock clevege but surfaces are dull and smooth
texture: fine grained/none visiblecolor: dullcleavage: breaks hard sheets or crumbles into blocks
metamorphic, non foliated, carbonate rocks, medium-corsegrained, can be scratched by nail, reacts with HCl
composition: shale, claystone, slatem clay, chlorite, micatexture: wavy, wrinkled foliationcolor: green, silver, brasscleavage: foliated
red, black, soccer ball cleavage
Igneous nexture that contains very course grains
Na-Plagioclase (oligoclase)
rock forming mineral, framework silicate, (Ca,Na)(Al,Si)4O8: description: pearly, hard, 2 direction cleavage (90º), medium, no streak, striations on cleavage plane
wilson cycle
divergence --> mtn building--> divergence
A fine-grained clastic rock composed of silt plus a significant component of clay, which causes it to break readily along bedding planes.
What rock has the coarsest foliation?
sedimentary rocks composed of SOLID PARTICLES (clasts) ERODED from other rocks - NON-INTERLOCKING GRAINS
Chemical weathering
involves reactions between minerals and water to produce dissolved ions and new minerals.
the process in which minerals from nearby rock will melt and are incorporated into the igneous body
Sedimentary Rock
PRESSURE; sediments form layers and over time form a rock; dirty looking with layers
Foliated Rock: Gneiss
Contains compositional layering often manifest as light and dark banding.• Represents separation of felsic minerals (light layers) with mafic minerals (dark layers).• High temperature and pressure rock.
the process by which HEAD, PRESSURE, and CHEMICAL REACTIONS deep within the Earth altar the MINERAL CONTENT and/or STRUCTURE of preexisting rock WITHOUT MELTING IT- ANY type of rock can be metamorphosed (igneous, sedimentary, metamorphic)
chemical sedimentary rocks
mineral constituents dissolved in water by chemical weathering may later precipitate as new mineral crystals if conditions of water temp, pressure, or element composition change appropriately.
The process by which glaciers change a landscape.
invisible grain
can't be seen with the naked eye
Inner Core
center layer; solid rock / dense metal; extremely hot
The 1600s
•! The earth, was ~6000 years old•! Landforms probably formed as a result of the great flood•! Earth formed October 23rd 4004 BC–!James Ussher, 1654
What kind of rock is rock salt?
sedimentary rock
Plate Boundaries
Plate boundaries stretch and separate. (move away from each other) As plates separate, the gash is filled with molten material rising from the asthenosphere.
Alfred Wegener
geologist who came up with theory of plate tectonics / wandering continents
Metamorphic processes: Metamorphic reaction
grows new mineral crystals through chemical reactions with protolith crystals.
Plate Boundaries
Plates slide past each other without creation or destruction of the lithosphere.
What three things cause rocks to metamorphize?
Heat, pressure, and chemicals.
Metamorphic processes: pressure solution
occurs when rock is squeezed more strongly in one direction than another, causing chemical reactions along grain boundaries, and causes grains to grow longer in one direction than another
andesitic, dacitic, and rhyolitic volcanoes
have more pyroclastic materials than basaltic eruptions, more explosive
Unconformity (Gaps in Record)
An unconformity is a period of non- deposition and/or erosion, representing missing time in the rock record.•Unconformities come in three varieties:–Angular unconformity: rocks below unconformity aretilted or folded.–Nonconformity: sedimentary rocks overlie igneous or metamorphic rocks.–Disconformity: unconformity occurring between otherwise flat layers of sedimentary rocks.• Can be difficult to detectHow can you find subtle unconformity?•! A marker that will tell us the “age” of the rocks.•! Fossils as time indicators•! Principle of Fossil Succession –!aka Faunal Succession –!aka Biotic Succession
2 examples of uses of Igneous Rocks
building materials and abrasives for polishing - pumice.
Difference between lava and magma
lava is molten material ejected from a volcano; magma is molten material below Earth's surface
What kind of layers does a flood create?
The largest particles are at the very bottom of the layer. Particles higher in the layer become increasingly smaller. The shows the the water carrying the sediment was slowing down.
A large pluton
cosmology-study of universe
sio2 greater than 67
black, lustrous, light, streak
economic mineral, sulfide, (Zn,Fe)S: description: submetal, medium hardness, perfect cleavage in 6 directions, heavy, yellow/brown streak
Coarse Grained
large, easy to see;
cinder is...
pyroclastic deposits
basaltic or andesitic
mechanical changes that cause the breakdown of rock due to the action of wind, ice, water , or plant's roots.
organic sedimentary rock formed from cemented pieces of shell
Evaporites: formed by evaporation of saltwater. Evaporation removes water, but ions stay behind, eventually building up to mineral precipitation.!•! Bonneville Salt Flats, Utah: salt beds deposited by ancient evaporating lake, i.e., lake with inlets but no outlets (closed basin).!•! May also occur in restricted marine basins, e.g., Mediterranean.!
reddish brown, dark, no luster, streak, big
any geological formation containing or conducting ground water, esp. one that supplies the water for wells, springs, etc.
weathering is the breaking down of Earth's rocks, soils, and minerals through direct contact with the planet's atmosphere, it also occurs in situ or "with no movement" and thus should not be confused with erosion
erosion involves the movement of rocks and minerals by agents such as water, ice, wind, and gravity
liquid water changed to water vapor (gas)
Darwin (1809-1882)
! Evolution by natural selection–!A reasonable hypothesis on why fossil succession worked–!Profoundly influenced by Lyell and gradualism •! In his view, evolution proceeded so slowlyas to be imperceptible to humans –!Required an old earth
normally purple and clear, 7 sides (rhombahedral) smooth and bumpy
chemical sediment
most ions dissolved in water eventually precipitate as solid ionic compounds
A region of rock that has been metamorphosed by contact metamorphism
forms when particles of other rocks or the remains of plants and animals are cemented together.
Water Cycle
Process of water changing from one form (state) to another
What are felsic rocks?
Light-colored, high silica igneous rocks. Most intusive rocks are felsic.
Absolute Time
• “Absolute” time = a real numerical age of the rock being dated–The use of the radioactive decay of certain elements to date the rock, with an error factor (+/-)
sediment is always deposited ON TOP of some other sediment or rock that is older - younger ON TOP of older
phaneritic texture...
magma cools slowly where warm rocks surrounds and insulates it deep beneath the surface, mineral crystals grow very slowly produce this coarse grained texture.
the visual and esp. tactile quality of a surface:
What is sandstone?
Clastic rock. Made of grains of quartz, up to 30% air(very porous), Rough, gritty, durable.
Radiometric Dating
•! The time it takes for half a given group of radioisotopes to decay is called the half-life.–! Parent = that which decays –! Daughter = decay product•! Half-lives are determined by laboratory observation, and are constant for a given isotope.•! The regular decay of atoms is like the ticking of a clock that can measure time.–! I.e., the proportion of parent-daughter isotopes in a given sample is unique with time.•! Selection of an isotope system to analyze depends on the scale of time you are attempting to measure, and the availability of minerals that contain appropriate parent- daughter systems.
Plate Boundaries
Plates collide head on into each other. One will plunge into the deeper mantle in a process called subduction. The overriding plate experiences volcanic activity. Earthquakes, mountains, volcanoes form from convergent boundaries.
igneous rocks
A type of rock that forms from the cooling of molten rock.
What are ferromagnesian minerals?
Iron magnesium silicates of a dark color. ????????????? What else?????????
Two types of weathering
•! Two main types: physical and chemical (plumbing snake vs. drano).!•! Physical (mechanical) weathering—breakup of rocks into unconnected grains or chunks (detritus).!
Density is..
a measure of the mass of a material divided by its volume.
Ionic bonds
one or more e- go from one atom to another giving them opposite charges so they attract eachother
What is a conchoidal fracture? Give examples.
A shell-shaped fratcure with sharp edges. Ex. Chert and obsidian
What is the texture of a rock?
How it feels (bumpy, smooth, etc.). Depends on the size, shape, and arrangement of its minerals' crystals.
sio2 55-67
location convergent margins
flat, plastic-like, layered
glass and knife blade
micro, grey, sodium rich
sedimentary, clastic, quartz, >2mm variable composition, rounded clasts
! Composed of cryptocrystalline (microscopic) quartz. !•! Formed from accumulation of plankton that grow silica shells (diatoms and radiolaria).!•! Shells later dissolve and re-crystallize to form cryptocrystalline quartz.!
olivine, pyroxene, amphibole, micas, serpentine, feldspar, quartz, garnet
igneous rock, glassy, frothy, felsic, note: light, floats on water
a naturally formed aggregate of mineral matter; forming a signficant part of the Earth's crust.
the apearance of a broken surface
looks circes and embedded shells, large
any geological formation that absorbs and holds water but does not transmit it at a sufficient rate to supply springs, wells, etc.
tethys sea
btw north america and south america
James Hutton (1726-1797)
•! Gentleman Farmer•! Concerned with soil, where it came from, where it was going.Main Ideas: •Crosscutting relationships Something that cuts across another must be younger than the material that’s being cut.–You can’t cut bread if it ain’t there yet! •! Faulting--break in rock w/ movement •! Igneous intrusions--dikes, sills, plutons• Principle of inclusion particles of other rocks are included in rock formation• Unconformities•The Rock Cycle(Deposition, Erosion, Upheaval, Deposition)•Hutton noticed the weathering of rocks (soil)•Sedimentary rocks were made of bits of weathered older rocks.•The unlithified counterparts to the strata were still forming and would eventually form rocks.•Revolution: a cyclic view
excellent cleave, not at 90, soft, scratched by steel
Luster is..
the property that describes how mineral surfaces reflect light
Name to example of metamorphic rock.
limestone and basalt
A property that can help identify a mineral
Sedimentary --> MetamorphicConglomerate(or granite)--> 1.Sandstone--> 2.Limestone--> 3.Shale--> 4.
1. Gneiss2. Quartzite3. Marble4. Slate then schist
Foliated Rock: Schist
Coarser grained rock, contains visible crystals of micas. Schistosity is an alignment of mica crystals resembling fish scales.• Higher temperature and with larger crystals than phyllite.• May contain other minerals including quartz, feldspars, and garnets.
parts of an older rock unit enclosed in an igneous rock body are inclusions
Hydrothermal metamorphic rocks
form where hot-fluid reactions with rock are the primary cause of metamorphism. Commonly host important metal-ore deposits.
Sedimentary rocks:A. Formation?B. Hard or soft?C. Primary or secondary?D. Origin?E. Main minerals?F. Main colors?G. Main textures?
A. Lithification (pressure and cement)B. SoftC. SecondaryD. Top, midE. Calcite, quartz, feldspar,hematite,micaF. Earth tonesG. clastic, chemical , organic
Formation of Solar System
•! Astronomers concluded that these red shifts were the result of the Doppler effect!–!“Phenomenon in which the frequency of wave energy appears to change when a moving source of wave energy passes an observer.”!
three processes most commonly cause heat transfer to rocks so they experience high temperature.
sediment burial
tectonic burial
magma intrusion
What are the three main kinds of sedimentary rock?
Clastic, chemical, organic.
rocks change as they
break apart, wear away; pressed and heated together; melt
Most physical properties are determined by...
atomic structure. EX. Graphite and Diamond, both made out of carbon but diamond is hard and graphite is a 2.
What kind of rock makes up Ship Rock in New Mexico?
Intrusive Igneous Rock
Igneous Rocks:A. Formation?B. Hard or soft?C. Primary or secondary?D. Origin?E. Main minerals?F. Main colors?G. Main textures?
A. Magma or lavaB. HardC. PrimaryD. Top, mid, lowE. Quartz, feldspars, micas(biotite, muscovite)F. Blacks, pinks, reds, whitesG. Coarse-grained, fine-grained, glassy, vesicular
Why do rocks buried deeper in the crust change?
they change because pressure and temperature increase with depth
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