L3: The Rock Cycle Flashcards
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Notes
Igenous Rocks
SOURCE: Melting of rocks in hot, deep crust and upper mantle
ROCK FORMING PROCESS: Crystallization (solidification of magma)
Sedimentary Rocks
SOURCE: Weathering and erosion of rocks exposed at surface
ROCK FORMING PROCESS Deposition, burial, and lithification
Metamorphic Rocks
SOURCE: Rocks under high temperatures and pressures in deep crust and upper mantle
ROCK FORMING PROCESS: Recrystallization in solid state of new minerals
How do igneous rocks form?
Form by the crystallization of magma
What is magma?
A mass of molten rock that originates from deep within the crust or upper mantle
How is magma formed? (the process)
- Temps. May reach >1000 degrees
- Slowly begins to cool beneath earth’s surface, microscopic crystals begin to form
- W/ sufficient time, these rocks may grow to several mm before the whole mass gets crystallized as a coarse grained igneous rock (aka intrusive igneous rocks)
- As magma moves up it begins to cool
- When magma erupts out of a volcano it cools and solidifies so rapidly that it does not have time to form large crystals (extrusive)
Underground = _______, above ground = _______
- Intrusive
- Extrusive
List and describe the types of volcanism
- Ocean-ocean convergence: Mafic to intermediate intrusives (plutonism), Mafic to intermediate extrusives (volcanism)
- Hot spot: basaltic intrusives, basaltic extrusives
- Spreading center: basaltic intrusives, basaltic extrusives
- Ocean-continent convergence Mafic to intermediate intrusives, Mafic to intermediate extrusives
What are extrusive igneous rocks?
Cool rapidly on earth’s surface and are fine grained
What are intrusive igneous rocks?
Cook slowly in earth’s interior, allowing large and coarse crystals to form
How are extrusive pyroclasts formed?
Form in violent eruptions from lava thrown high in the air
How are porphyritic crystals formed
Start to grow beneath Earth’s surface. Some crystals grow large, but the remaining melt cools faster, forming smaller crystals either bc its erupted to the surface or bc its intruded close to earth’s surface
List examples of mafic minerals.
- Basalt
- Gabbro
List examples of felsic minerals
- Rhyolite
- Granite
Define sedimentation
Found on earth’s surface as loose particles (ex. Sand, silt, clay)
What are clastic sediments?
Particles that are physically deposited by running water, wind, or ice
What is lithification?
- When sediments are buried, compacted, and cemented
- When lithification occurs sand, silt, clay = sandstone, siltstone, shale
Define chemical/biochemical elements.
- Sediments of new mineral grains that form by precipitation from water after a state or supersaturation is achieved
- Bio: Forms a skeleton
- Chem: Sal/sea salt (precipitation)
Define the stages of sedimentary rock formation.
- Weathering: physically and chemically breaks down rock
- Erosion: Carries away particles produced by weathering (ex. Carried by wind or glaciers)
- Transportation: Move particles downhill via streams, glaciers, wind
- Deposition (aka sedimentation): Occurs when particles settle out or dissolved minerals precipitate
- Burial: Occurs as layers of sediment accumulate and compact previous layers
Diagenesis: Lithifies the sediment to make sedimentary rocks (alter things)
______ -> _________ -> sedimentation
- Erosion
- Transport
What does it mean to make a mineral stable?
The slower it reacts
What is Bowen’s reaction?
Determines melt/crystallization order in igneous rocks
What are the 3 different sediments that result in different sedimentary rocks?
- Fine grained
- Coarse grained
- Organic matter
What are metamorphic rocks?
- Produced when high temps and high pressures deep in the Earth’s crust cause existing rocks to change their mineralogy, texture, or chemical composition while maintaining the solid form
- Temp. range is typically between 700° - 2500°
What is regional metamorphism?
- Occurs when high temps. + pressures extend over large regions, as happens during mountain building
- Convergent plate boundaries occurs @ moderate to deep levels under moderate to ultra-high pressures and high temps
What is contact metamorphism?
- High temperatures are restricted to smaller areas
- Ex. rocks near and in contact with an intrusion
- Affects a thin zone of country rock around an igneous intrusion
Types of metamorphism
Regional, contact
What 4 elements need to be present to complete the rock cycle
Water, biosphere, ecology, atmosphere
Define the stages in the rock cycle.
Check lecture diagrams
What are the links to global climate?
Check notebook
