Term
|
Definition
• Clastic or detritial
change in energy
• Chemical
change in environmental conditions |
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Term
| Clastic Sedimentary Rocks |
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Definition
• Solid particles (grains)
• Grains settle out
• Mechanical precipitation
• Change in energy - high to low
• Breccia/Conglomerate
• Sandstone
– Arkose
– Quartz sandstone
• Siltstone
• Shale |
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Term
| Chemical Sedimentary rocks |
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Definition
• Dissolved chemicals
• Growth of crystals from solution
• Chemical precipitation
• Change in environmental conditions
• Triggers of change
– inorganic: evaporation or cooling
– organic: plants and animals
• Limestone
• Dolostone
• Chert
• Gypsum
• Salts |
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Term
|
Definition
• Clastic
– clastic sedimentary
rocks
• Crystalline
– chemical
sedimentary rocks |
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Term
|
Definition
• To turn into stone or lithify
• Stages:
– Compaction
– Cementation
– Recrystallization |
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Term
|
Definition
• Layered arrangement
• Parallel or horizontal layering
• Cross-bedding or cross-strata |
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Term
|
Definition
• Produces sediment
• Happens to all objects moving or stationary
• First step in producing sedimentary rocks
• Produces soils
• Allows concentration of ore and minerals
• Produces useful resources |
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Term
|
Definition
• Disintegration
• physical or
mechanical
• change in size
(smaller)
• same chemistry
• Decomposition
• chemical or
dissolution etc.
• minerals disintegrate
• change in chemistry |
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Term
|
Definition
• Abrasion
• Expansion
– growth of ice crystals
– growth of salt crystals
– unloading or pressure release
– change in ambient temperature
• Activity of organisms |
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Term
|
Definition
• Solid (ice) less dense than liquid
• Water expands when it freezes
• Volume increase up to 9%
• Frost wedging
• Frost heaving |
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Term
|
Definition
• Minerals unstable at surface conditions
• Chemicals leached out of
minerals/rocks
• Atmospheric gases react with minerals
• Minerals dissolve
• New minerals form |
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Term
|
Definition
• Water
– carbonic acid dissolved in natural water
– acid rain
• Air
– atmospheric gases
– oxygen
– carbon dioxide |
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Term
|
Definition
• Minerals weather at different rates
• In the order of Bowen’s Reaction Series
• First to go
– olivine
– Ca-rich plagioclase
• Last to go
– quartz
– Na-rich plagioclase |
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Term
|
Definition
• Rounding minerals (rocks)
• Smoothing of minerals (rocks)
• Minerals (rocks) broken into smaller pieces
• New minerals form
• Minerals completely dissolve
• Ions go into solution |
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Term
|
Definition
a) original mineral = new mineral + ions
(solution)
b) original mineral = ions (solution)
c) original mineral = original mineral
(smaller, rounder, smoother) |
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Term
| Final Weathering Products |
|
Definition
• Clays
• Quartz
• Silica
• Oxides
• Ions
• Concentration of gems and precious metals
(e.g., platinum, gold, diamond) |
|
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Term
|
Definition
• Exfoliation or spalling
• Rounding and Smoothing
• Differential weathering according to
rock hardness
• Weathering of a rock consisting of many minerals |
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Term
|
Definition
• One of our most vital resource
• A regolith
• Unconsolidated mat on top of bedrock
• Capable of supporting rooted plants
• Note engineers define soil as “anything loose”
• Soils take thousands of years to develop and
once gone don’t “grow” back quickly |
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Term
|
Definition
• Development of regolith into soil
• Distinct horizontal layers develop
• All soils have these layers
• However, more developed in some
areas, less in others (or missing) |
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Term
|
Definition
• Loose, unconsolidated, solid particles
(grains) resulting from weathering
• Grains -
– size
– shape
– sorting |
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Term
| Grain Size Classification |
|
Definition
• Gravel > 2mm
– boulders, cobbles, pebbles
• Sand 2 to 1/16 mm
• Silt 1/16 to 1/256 mm
• Clay < 1/256 mm
• “Mud” = silt and clay |
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Term
|
Definition
• edgy and irregular
• round and smooth |
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Term
|
Definition
• poorly sorted
– grains of similar size
• well sorted
– grains of uneven size
• Sorting according to:
– size
– shape
– specific gravity
– durability |
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Term
|
Definition
• North Atlantic ~ 60,000 sq. miles
• Highest peak 6,600 feet
• Glaciers cover 15%
• Volcanic
• Rich fishing grounds
• Main natural resource - water |
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Term
|
Definition
• Settled in 874AD by Norwegians and Celts
• “Althing” - Parlament founded in 900 AD
• Language: Icelandic (“old Norse”)
• Rich literary culture - the “Sagas”
• Capital: Reykjavik (“Bjork” & “Sigur Ros”)
• Main export: fish and “brains”
• Current population 290,000 |
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Term
|
Definition
• Formed 65 million years ago
• A “hotspot” on a Mid-Ocean ridge
• Produced 1/3 of all lava on Earth in the last
500 yrs
• 250 eruptions since settlement (874)
• On average one eruption every five years
• Contains every type of volcano found on Earth |
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Term
|
Definition
• Mostly basaltic
• Shield Volcanoes - monogenetic
• Fissure eruptions - monogenetic
• Subglacial eruptions
• Central Volcanoes - one million years
• Lava and tephra |
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Term
|
Definition
• Largest historic lava flow on Earth
• 25 km long fissure
• 12-15 km3 lava
• 400-500 million tons of volcanic gas
• Eruption lasted less than a year
• Killed 75% of livestock
• 20% of the Icelandic population died of ensuing famine |
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Term
|
Definition
• Inhabited island
• Population 5000
• Eruption at night
• Destroyed a large part of the town
• Sprayed water on the lava to halt its
flow |
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Term
|
Definition
• Grimsvotn
• Subglacial
• Catastrophic floods
• Once every 5 years
• Jokulhlaup
• Largest floods on Earth
• Very dangerous |
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Term
|
Definition
• Iceland’s most fameous volcano
• Entrance to Hell?
• Central volcano
• Active for 10,000 yrs
• Very large eruptions
• Magma chamber??
1947
1970
2000 |
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Term
|
Definition
|
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Term
|
Definition
• Strato-Volcano
• Last major eruption in 1980
• Lava dome plugged conduit
• Around fifty people perished
• Currently Active!
last eruption 2005 |
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Term
| Classification of Igneous Rocks |
|
Definition
• Grain size
– glassy
– fine-grained (aphanitic)
– coarse-grained (phaneritic)
• Minerals
– type
– relative quantity
• Chemical composition
– silica or SiO2 |
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Term
| Magma Chemistry Extrusive |
|
Definition
From high to low silica content
Felsic or acidic---- Rhyolite
intermediate-------- Andesite
Mafic or basic------ Basalt |
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Term
| Magma Chemistry intrusive |
|
Definition
From high to low silica content
Felsic or acidic---- Granite
intermediate-------- Diorite
Mafic or basic------ Gobbro |
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Term
|
Definition
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Term
|
Definition
• Rocks melt because the melting point of one
or all minerals is exceeded
• Melting point - the temperature at which a
mineral or rock melts
• Mineral melting point is influenced by
– fluid and gas content
– pressure
– presence of other minerals |
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Term
|
Definition
• Total melting
– the mineral with the highest melting point melts
• Partial melting
– temperature is below the highest mineral melting
point but above the lowest
– insufficient time for complete melting |
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Term
|
Definition
• Describes the order in which minerals
form as a rock crystallizes (or melts)
• As the minerals grow the chemistry of
the residual liquid changes
• Allows one to generate different rock
types
• Why does crystallization lead to
change in melt chemistry? |
|
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Term
|
Definition
• Rocks can have many mineral types
• Minerals differ in composition
• Their melting points must differ
• As minerals crystallize the magma changes
• High-temperature minerals are mafic
• Low-temperature minerals are felsic |
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Term
|
Definition
• Basalt/Gabbro
– partial melting of upper mantle rocks
– residue is peridotite
• Andesite/Diorite
– partial melting of more mafic rocks
– crystal fractionation of more mafic rocks
– magma mixing - basalt and rhyolite
• Rhyolite/Granite
– partial melting
– crystal fractionation of more “mafic” rocks |
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