Geology
Terms
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- luster
- appearance or quality of light reflected from the surface of a mineral; metallic and nonmetallic
- pahoehoe
- a lava flow with smoothh to ropy surface
- Moh's hardness scale
- measures hardness from 1 to 10
- talus
- accumulation of rock debris at the base of a cliff
- Nonsilicates
- ex-calcite, dolomite, halite, gypsum, oxides
- driving forces for plate tectonics
- convection cell, ridge push, slab pull
- Coal
- organic. Lignite, biuminous, anthrocite
- cobble
- 64-256mm, forms conglomerate or breccia
- glassy
- no crystals, high silicate content
- Halite
- Evaporite, NaCl
- clay minerals
- when light or dark silicates react with water at the surface, sheetlike structure, impermeable
- magma
- underground, contains volatiles-CO2, H2O, SO2
- Intrusive rocks
- igneous activity that occurs below the surface, take longer for it to cool
- block lava
- lava with a surface of angular blocks, andesitic and rhyolitic composition
- progression of foliated rock types
- shale, slate, phyllite, schist, gneiss, amphibolite
- ice wedging
- water gets in cracks in rocks, freezes and expands
- viscosity
- resistance to flow
- Palezoic era
- ancient life, 540-817 million
- Atmosphere
- gases that surround the earth
- strain
- an irreversible change in the shape and size of a rock body caused by stress
- convergent plate boundaries
- a boundary where two plates move together, oceanic sinks beneath continental
- crystal settling
- as magma crystallizes the minerals that formed earlier are denser than the liquid and settle out
- metamorphic rock
- changing of the rock, recrystallizatino due to pressure, temperature, pore fluids, and it depends on the parent rock type. the rock must remain solid
- dark/ferromagnesian/mafic minerals
- iron and magnesium, dark colors, ex-olivine, pyroxene, amphibole, mica (biotite)
- Cementation
- material precipitates from water that percolates through the sediment, open spaces are filled and particles join together. calcite, silica (makes it very hard), iron oxides (reddish/orange tint)
- phanerozoic eon
- 541 million years ago. "explosion of life"
- Aphanitic
- microscopic crystals, vesicles-gas bubles, extrusive
- calcite
- in limestone, CaCO3
- transform plate boundaries
- a boundary where two plates slide past one another without creating or destroying lithosphere
- turbidity current
- a downslope movement of dense, sediment laden watercreated when sand and mud on the continental shelf and slope are dislodge and thrown into suspension
- angular conformity
- an unconmfomity where the older layers are at a differnt angle than the younger rocks
- foliated texture
- leafy, layered appearance.
- minerals
- can't be man-made, can't be organic, must be a solid and have a crystalline structure, its composition must be w/i a range but it can vary w/i the range
- sheeting
- outer surface of rocks will break off due to reduction in pressure fom where it formed
- cleavage
- place between patterns where a mineral can easily break apart
- tyeps of radioactive decay
- alpha, beta and gamma
- Steps required for formation of Sedimentary rocks
- Weathering, transportation, deposition, cementation
- Hot spots
- hot mantle is near the surface
- crust
- inner layer of earth's compositional layers, made up an iron-nickel alloy, magnetic field
- oceanic crust
- basaltic, thinner, much younger, denser than continental
- Gypsum
- CaSO4 2H20
- Four components of soil
- mineral 45%, humus 5%, water and air 50%
- original horizontality
- layers are put down horizontally
- mantle
- 82% of earth's volume, middle layer of earth's compositional layers
- sand size
- 1/16-2mm forms sandstone
- Extrusive rocks
- igneous activity that occurs at the surface
- mesophere
- pressure is high so it acts like a solid
- hydrolysis/acid hydrolysis
- reaction between water and minerals and acids
- soil horizons
- O (organic), A (humus), E (bleached and leached, no organic left), B (subsoil that collects everything from E), C (partially broken bedrock)
- Dolomite
- CaCO3, some Ca are replaced with Mg,
- pyroclastic texture
- "fire broken", consolidation of individual rock fragments that are ejected during a violent volcanic eruption
- specific gravity
- density of rock to density of water
- hardness
- the ability of a mineral to scratch another, resistance to abrasion.
- silicate minerals
- 95% of crust, made up SiO4 (-4)
- correlation
- fill in the gaps. use the criteria of mineral composition, sequence and thickness
- regolith
- layers of broken up rock, uppermost layer is the soil
- detrital
- rocks that form from the accumulation of materialsthat originate and are transported as solid particles derived from both mechanical and chemical weathering
- Geomagnetic reversals
- magnetic poles switch
- streak
- the color of a mineral in powdered form
- boulder
- greater than 256mm, forms conglomerate or breccia
- lava
- at the surface, lost volatiles
- Mid-Atlantic Ridge
- mantle welling up, pushing oceanic plates apart to form new oceanic crust
- unconformity
- interruption/break inthe record, gap in time
- athenosphere
- flows due to melting, allows lithosphere to move
- inclusions
- rocks that are included are older than the rocks that are including them
- mantle plume
- divergent boundaries where mantle is coming up
- stress
- force per unit area
- Mic (Muscovite)
- 1 dimension cleavage-sheets
- Igneous rock
- rock formed from the recrystallization of magma
- crystal form
- the external appearance of a mineral determined by its internal arrangement of atoms
- color
- physical property of a mineral that is a good indicator but can easily lead you astray
- Silt size
- 1/256-1/16mm forms shale, mudstone, siltstone
- mesozoic era
- 417-65 million
- fossil sucession
- simpler life forms older than more complex life forms
- dissolution
- water dissolves rock
- slab pull
- the colder the rock the more dense it becomes so it sinks and pulls the rest of the slab along
- cross cutting
- whatever is doing the cutting is younger than what it is cutting through
- Nonferrogmagnesian/felsic/light minerals
- rich in Si, Al (3+), lower density/specific gravity, tend to be lighter colored ex- feldspar, Quartz, Mica (Muscovite)
- ridge push
- at the spreading centers, the elevation is higher so gravity pulls it down
- biosphere
- living things on planet
- aa
- a lava flow that has a jagged, blocky surface
- Lithosphere
- solid outer sphere of earth
- deep ocean trench
- deepest part of ocean basin; narrow, elongated depression of the sea floor
- pumice
- a light colored glassy vesicular rock formed from pyroclastic materials
- Clay size
- less than 1/256mm forms shale, mudstone, siltstone
- superposition
- layer on top is younger than the layer on the bottom
- Crust
- consists of oceanic and continental, one of earth's compositional layers
- evidences for pangaea
- general "fit", Fossils (Mesosaurus and Glossopteris), rock types and structures (appalachians), Paleoclimatic evidence (coal in us suggests it was once near equater and evidence of glaciers in australia and india), Paleomagneticism
- continental
- granitic, thicker, older, less dense than oceanic
- Quartz
- hard, SiO2
- Canezoic era
- 65 to present, dinosaurs gone
- magma mixing
- altering the composition of a magma through the mixing of material from another magma body
- pebble
- 4-63mm, forms conglomerate or breccia
- assimilation
- incorporating the rock surrounding the magma into the magma composition
- Limestone
- made up of Calcium carbonate, chemical origin-oolitic (spheres) and travertine. bio origin- coral reefs, coquina (shells), chalk
- liquid outer core
- allows for magnetic field
- chert
- SiO2, formed from Quartz
- Pillow lava
- lava extruded under water so it solidifies as soon as water hits it
- solid inner core
- allows for magnetic field
- Scoria
- vesicular ejecta that is the product of basaltic lava
- convection cell
- as convergent boundary pulls crust down, it cycles magma back up to the surface
- Porphyrtic
- Large (phenocrysts) and microscopic (groundmass) crystals
- granule
- 2-4mm, forms conglomerate or breccia
- Hydrosphere
- the portion of earth consisting of water 71%
- Pegmatitic
- very large cystals, greater than 1 cm
- Uniformitarianism
- world that is seen today has the same processes as in the past and is a result of those processes
- dolostone
- pass Mg solution through calcite to exchange calcium for mg in CaCO3. formed from dolomite
- divergent plate boundaries
- boundary where two plates move apart resulting in the upwelling of material from the mantle to create new seafloor
- Phaneritic
- visible crystals, intrusive
- Geosphere
- solid earth
- Chemical sedimentary rocks
- consists of material that was precipitated from water by either inorganic or organic means
- Feldspar
- K feldspar- pink (orthoclase), Plagioclase feldspar-striations (Na (+) and Ca (2+)
- pre-cambrian eon
- before any significant life