Fichas
Exploring Planet Earth
Fichas del conjunto (127)
- 1first atoms to form and when in the universeHydrogen and Helium, 300,000 after the big bang
- 2stellar nucleo synthesisfusion in stars formed increasingly heavy elements, up to Fe
- 3why are supernovae important to the creation of solar systemformed elements heavier than Fe
-these heavier elements along with hydrogen and helium created our solar system - 4what are the most common elements in nebulaehydrogen and helium
- 5when did our solar system form and the steps5.5-4.6 Ga after the big bang
- 6nebular theorydust and dense elements orbited the the sun, with lighter elements (volatile) on the outside. This dust formed the terrestrial planets. Gases formed the outer planets. Rapid rotation created a flat disk
- 7planetisimala minute planet; a body that could or did come together with many others under gravitation to form a planet
- 8Jovian planetsGas and ice giants formed from the remains of the nebula
- 9solar windthe continuous flow of charged particles from the sun which permeates the solar system.
- 10closest massive star forming factoryOrion. 1,500 light years away
- 11chondrite meteoritesoriginal solar system materials, the building blocks for planet earth.
- 12stony (achondrites)Like earth surface rocks
- 13chemical composition of the earth (top 8 elements)
- 14general layers of the earth
- 15what do meteorites tell us about earth
- 16numerical dating (geochronology)using solid facts to date. Started with radiometric dating using isotopes in early 20th century
- 17precambrianaccounts for 84% of geological time
-before macroscopic life - 18what is an isotope?-Isotope: different number of neutrons so different atomic mass
- 19Carbon isotope decayHalf life: 5730
- 20what is a half lifeThe time it takes for half of the parent isotope to decay to daughter isotope
- 21difference between continental and oceanic crust-continental and oceanic crust
-continental crust is thick, whereas the oceanic crust is thin
-composition is different
-continental crust is lighter (less dense) rock (light silicates)
-oceanic crust is heavier (more dense) rock (heavier silicates)
-continental crust is thick around mountains and thin below the ocean.
-continental Rocks are felsic: lighter silicate minerals (mainly made of Felds bar)
-oceanic rocks are mafic rocks - 22Lecture 3Lecture 3
- 23The great oxigenation-The first couple billion years, there was no oxygen
-at 2.4 billion years, we get the great oxygenation
-at this point, there was enough oxygen produced by bacteria to see oxygenation of minerals in the ocean (rusting) - 24Unstable isotoperadioactive decay
- 25Plate boundrieswe have 3 different types of plate boundaries
subduction, collision and transform boundaries - 26AtomAn atom is the basic building block of chemistry. It is the smallest unit into which matter can be divided without the release of electrically charged particles.
- 27moleculeTwo or more atoms bonded together
- 28Ionic bondingExchange of electrons. 90% of minerals use ionic bonding
- 29metallic bondingcovalent: all neibouring atoms share electrons
- 30Hydrogen bonds and van der waalsHydrogen bonds: polarity
van der waals: weak attraction between covalently bonded molecules - 31graphite and diamonddiamond formed from immense pressure. Same chemical formula
- 32mineral structure: affected by and and controlled byControlled by: atomic size, charge and bonds
affected by: temp, pressure and composition of environment - 33Minerals are classified by groups that share a common : ???anion or anionic group
EG.
Silicates,
carbonates
oxides
sulfides
Halides - 343 bigest minerals in the rock worldQuartz, feldspar and mica
- 35Strongest bonding anionsSilica to oxygen (silicates) (50% ionic, 50% covalent bonding)
- 36most common anion groupoxides
- 37Identify minerals through: ???luster, hardness and cleavage
- 38lusterThe way minerals scatter light.
categories: non-metalic and metalic - 39hardnessScratchability, depends on bond strength
- 40clevagetendancy to break along planes of weakness
- 41fractureirregular breakage, not on planes of weakness
- 42habit:crystal form
- 43what is a rocka coherent, naturally occurring solid containing an agreggate of minerals
- 44mineralogyrelative proportion of constituent minerals
-reflects chemical composition - 45TextureSize, shape and arrangement of rock's minerals
- 46Rock cycle
- 47Igneous rocksFormed by crystallizing from a melt
- 48igneous textureInterlocking crystals
- 49Intrusive rocks (plutonic)solidified slowly in the earth, often have big minerals
- 50Volcanic (extrusive) rockssolidified quickly at surface. Often has small minerals
- 51Sedimentary rocksbreakdown of other rocks at the earth's surface, grains held together by cement
- 52metamorphic rockschange from one rock to another through high temp and pressure, agragate of mineral grains
- 53where magma formsSubduction (convergent plate boundaries)
Divergent plate boundaries (spreading ridges)
-hot spots - 54major minerals in igneous rocksPlagioclase, K-feldspar, quartz, mica, amphibole, pyroxene, olivine
- 55Decompression meltingupward movement of the earth's mantle to a lower pressure area higher up.
Continental rifts, mid ocean ridges, hot spots. melting happens even when temperature doesn't increase - 56partial meltingproduce mafic magma, gabbro or basalt.
local geotherm intersects the solidus line (part of decompression melting). Partial melts have higher silica then parent - 57melting by heat transferHot magma rising melts the crust layer and forms magma with different composition. cool magma produces smoke, hot magma does not
- 58addition of volititles through subductionin the earth, the volitiles rise, carrying magma with it to create volcanoes. Causes dehydration reactions for rocks in it's path
- 59Mountain building crust meltThickening continental crust during orogenesis increases geothermal gradient
- 60fractional crystalizationFe, Mg and Ca crystalize first and leftover rock is higher in silica
- 61Assimilation of fluid at subduction zones causes: ???change in magma composition,
- 62Dikes and sillsplanar intrusions (intrusive) that cut across or intrude parallel layers. Can spread or raise the crust
- 63a pluton is a: ???Crystalized magma chamber
- 64Clastic sedimentary rocksformed by erosion, weathering, transportation, deposition or lithification
- 65high energy/low energy in water
- 66Lithificationthe process by which clay, sand, and other sediments on the bottom of the ocean or other bodies of water are slowly compacted into rocks from the weight of overlying sediments
- 67Classifying sedimentary rocks (textural features)
- 68Gravel: breccia and conglomerate differencesBreccia: consolidated rubble with angular clasts
Conglomerate: consolidated gravel, rounded - 69Sandstone featuresMostly made of quartz, compacted sand. Very small grains
- 70Silt and mudsilt has larger particles than mud. Siltstone: consolidated silt
mudstone: consolidated mud - 71Classifying sandstoneQuartz arenite: 90% quartz
lithic arenite: has sand grains in it
Feldspathic arenite: Contains lots of feldspar (alumino-silicate minerals) - 72Clastic rock classificationGrain size: closer to source, farther from source
Sorting: well to poorly
maturity
angularity - 73chemical sedimentary rocksFrom the precipitation of materials from solution: lime stone (calcite), chert (silicate), dolomite (mg and Ca)
- 74evaporitesprecipitated from solution and concentrated by evaporation: Gypsum and halite
- 75biochemical sedimentarymade of debris from living organisms
- 76Allochthonous vs autochthonousAllochthonous objects have been displaced from their original site of origin, in contrast to autochthonous (auto,' self') objects that remain indigenous or in situ.
- 77organic sedimentderived from organic material
- 78bedding an laminationlayers
-Small layers = lamination - 79Ripple marksAsymmetric and symmetric ripples
- 80cross beddingformed from water
- 81graded beddingcaused by falling or slumping sediment that arranges itself from heaviest to lightest (course to fine grained)
- 82Stratigraphic formationlayered formation, can use relative age dating on
- 83examples of chemical weatheringacid rain, oxidation, hydrolysis
- 84where do rocks break and from whatbedding planes, fractures and joints.
happens due to freezing or heating (contraction) - 85jointsfractures perpendicular to plane of weakness. Form to acomodate change in shape. Often formed by stress
- 86Talus?naturally occurring slope from fallen rocks
- 87physical weathering examplesburrowing creatures, tree root wedging, rivers, lakes, glaciers
- 88physical weathering defbreakdown of rock by physical process. does not alter chemical composition
- 89chemical weathering - dissolutionforms pitted surface of rock since ions are dissolved from the rock into the water
- 90minerals prone to dissolutioncalcite, dolomite (carbonate minerals)
- 91describe chemical weathering of graniteGranite has biotite, quartz and feldspar. rock breaks. K-spar turns to clay, biotite turns to clay. clay gets washed away, leaving quartz.
- 92relative abundance of sedimentary rocks
- 93Hydrolysiswater added, breaks feldspar to clay and ions
- 94iron Oxidation (hematite)addition of oxygen and water to pyroxene releases silica and iron oxide
- 95effects of chemical weatheringleaches minerals and silica, creates water bearing minerals, ground water becomes less acidic
- 96why are sedimentary rocks useful?grain size, rounding, sorting and composition tells us about transport distance and medium. Also depositional environment
- 97uniformatarianismpresent is the key to the past!!
- 98examples of depositional environmentsalluvial fan, rivers, streams, river delta
- 99metamorphism is a result of:???Temperature (heat flow), pressure (differential or confining), composition (fluid reacts with minerals and carries them in or out; metasomatism)
- 100texture of a metamorphic rockinterlocking crystals accompanied by other crystalline rocks. foliation only happens in metamorphic rocks.
- 101re-crystallizationprotolith changes grain size. All in solid state (no melting
- 102pressure dissolutionthe grains (crystals) partly dissolve
eg. circular to elliptical grains - 103plastic deformationis re-crystallization with deferential stress. Internally change the shape of grains (flow and deform)
- 104neocrystallizationgrowth of new minerals. Often occurs when you jam a sedimentary rock down deep
- 105what kind of minerals does neocrystallization create?Index minerals: chlorite, epidote, muscovite, biotite, hornblend, staurolite, garnet, pyroxene
- 106what is one place where we see pressure and temperature work together to metamorphose?Mountain building events
- 107which type of pressure do you see when you go deep in the earth?lithostatic pressure (vertical compression)
- 108normal and shear stressNormal: perpendicular
shear, sideways motion - 109under what conditions do we get blue schist?high pressure, low temperature. Often water subduction (ocean lithosphere is shoved down)
- 110high or low grade metamorphism locationlow grade is generally close to the surface and high grade is deeper down. Increase in temp and pressure = higher grade
- 111difference between foliated and non-foliated texturesfoliated: planar arrangement of minerals
non-foliated: crystalline texture with no alignment of minerals - 112foliationdue to plastic deformation, compression. new minerals can grow parallel to the foliation
- 113slaty cleavagefine grained foliated planes
- 114phylitic foliationbigger grains, start to see new minerals (often micas)
- 115schistose foliationlarge platy minerals (micas), larger grain size. often see index minerals
- 116gneissic foliationbanding is present: alternating layers of different minerals
- 117magmatiteVery deformed metamorphic rocks. very high grade. often see pockets of melt
- 118metamorphic grade
- 119types of metamorphismregional, contact, dynamic, hydrothermal
- 120example of regional metamorphismunder mountain building area or rifting
- 121example of contact metamorphismIgneous intrusion heats the rocks around it. high grade when close, low grade when far. Often turns rocks to hornfels
- 122example of dynamic metamorphismfaulting and to shear stress increase temp and pressure. forms mylonite
- 123example of hydrothermal metamorphismat mid ocean ridge, water seeps down, gets heated then brings basalt rocks to the surface with it.
- 124how do metamorphic rocks get to the surface?exhumation causes mountains, Collapse of mountain belts due to erosion
- 125How is oceanic crust created?from decompression melting. Oceanic crust is gabbro, with the very upper part being basalt. New gabbro pulls the ocean apart.
- 126what is ryolite?half mafic, half felsic. Formed from heat transfer
- 127Mafic vs FelsicMafic: iron and magnesium rich (heavier minerals)
Felsic :silica rich (lighter minerals)
Información
- Descripción
- Exploring Planet Earth flash cards. Types of rocks, beginnings of the universe and composition of the earth
- Creado por
- Erin Duxbury
- Visitas
- 16
- Valoración