Final Study Guide Flashcards
Definition of a Mineral
a naturallly occuring inorganic solid having a specific elemental composition and specific arrangement of atoms
what is Serpentine rock composed of
Lizardite, antigonite, chrysolite
where does chrysolite form
in conditions analougous to where geodes form, fluids move through voids in rocks and minerals precipitate from those fluids
examples of three types of cleavage
mica-perfect 1 direction
halite-perfect 3 directions
Quart-no cleavage
why is graphite soft
because it consists of covalently bonded layers of hexagons linked by weak bonds
what is an intrusive igneous rock
a rock that forms from cooled magma
what is magma
liquid earth that is below the surface
what is extrusive igneous rock
rock that forms from cooled lava
what is lava
molten earth that is above the earths surface
what is a batholith
a mass of intrusive igneous rock that is a few km in size. it is a magma chamber
what is a sill
a tabular pluton that is parallel to layers in layered rocks
what is a dike
a tabular pluton that in a cross section is relatively thin and cuts across layers in layered rocks. typically less than 1.5m thick and 10s to 100s of meters long
what is bowens reaction series
predicts the order that minerals form when solidifying from magma. indicates mafic forms first then silicic. also predicts order minerals melt
how are igneous rocks named
on the basis of mineral composition
info about silic/felsic rocks
contain abundent feldspar and silica. most continental crust is silic or intermediate
composition of intermediate rocks
mostly plagioclase, pyroxene, and amphihole, like to o quartz
what are mafic rocks
magnesium and iron rich rocks. mostly plagioclase and pyroxene. oceanic crust is mafic
what are ultra mafic rocks
mostly olivine and pyroxene. can have minor plagroclase. The mantle is untra mafic.
peridotite is intrusive
komatite is extrusive
what is partial melting
when mass of rock subjected to melting conditions . minerals with lowest melting point melt first. only parts of the mass melt.
where does magma form
partial meltinig at subduction zones=litosphere into mantle causes melting
dewatering of the downward slab=water is released from subducted plate which lowered the melting point
decomposition melting in continental thnning areas= as lithosphere is thinned aspthenosphere rises and decompresses, this lowers the melting point
seafloor spreading centers=causes rocks to rise which induces partial melting
defenition of soil
where the atmosphere, hydrosphere, lithosphere, and biosphere interact
what is pedogenesis
the process of soil formation
what is translocation
the definitive pedogenic process. downward movement of solid soil particles or ions in solution
how are ditrital sedimentary rocks classified
are assigned on the basis of clast size and in rocks consisting predominantly of clasts having median diameters larger than 2 mm, also on the basis of clast shape
how does deposition of detrital rocks happen
occurs when there is insufficient power for a system of river or wind to transplant sediments of a given size
what is slate
a metamorphic rock which has crystals that are too small to see without magnification
what is schist
a metamorphic rock that which has crystals that are visible to the naked eye
what are index minerals
indicate relatively precise ranges of temperatures and pressures causing metamorphism, index minerals are used to define metamorphic facies
what do different metamorphic facies represent
they reflect different tectonic settings a d certain tectonic settings
what are reverse faults
hanging wall moves up relative to footwall. form as a result of compression. shorten and thicken the earths crust. dip-slip faults
what are strike slip faults
form as a consequece of a horizontal shear stress in earths crust
what are normal faults
hanging wall moves down relative to the footwall. forms as a result of tension. extends and thins the earths crust. dip-slip faults
what are transform faults
where two plates move past each other
what are releasing bends
form at right bends or steps anlong right lateral strike slip faults, because fault geometry causes localized tension and extension
what are restraining bends
form at left bends or steps allong right lateral faults, because fault geometry causes localized tension and extension
what is a brittle strain
change in shape or position accomodated along fractures
what is elastic strain
said of a body in which strains are instantly and totally recovered
what is evidence for subduction
wadati benioff zones
mineral glaucophane
blueschist facies metamorphic rock
when do earthquakes occur
when elastic strain overcomes friction of a fault or elastic strain overcomes the mechanical strength of rocks. rocks move past eachother allong a fracture, elastic straiin is recovered and rocks regain pre elastic shape, as the rocks snap back earthquake waves are generated
what is liquefaction
occurs in cohesonless soil or sediment. liquefaction is a transformation of material that is behaving like a solid to a material that is behaving like a fluid temporarily
why is it safer to build on fully lithified rock
when surface waves pass through unconsolidated sediment resonance occurs because they oscillate at similar periods as the waves. when the waves pass through fully lithified rock, dampening occurs because they oscilate at different periods
what is the 1st family of earthquake waves
body waves and they travel underground in all directions. include p and S waves
what are p waves
body waves, are the fastest and travel like a slinky
what are S waves
body waves, cant pass through liquids, move like a cracked whip
what is the 2nd family of earthquake waves
how body waves manifest on the earths surface, include love/long waves and rayleigh waves
what are Love/Long waves
shearing motion, perpendicular to the direction of travel and travel more rapidly than rayeigh waves
what are Rayleigh waves
give the rocking sensation, similar to water waves, both vetical and horizontal movement
why are tsunamis so destructive
travel and speeds up to 518mph
long period so water doesent recede quickly
long waves so large volume of water causes energetic collisons
reach the coast in sets of unpredictable number of waves
what causes tsunamis
form when the sea floor is ruptured durring and earthquake
definition of a stream
a channelized body of water, links in the hydrological cycle that are the fundamental landscape sculpting agents. exist because of topographic relief of earths surface
what is a graded stream
a stream that is adjusted to its base level, over 1000 year time scale is neither lowers or raises its bed. requires stable base level over 1000 year timescale. shows that streams are laxy and will do as little work as possible
what is a disolved load
products of checmial weathering lthat are in solution or incolloidal suspension
what is a suspeded load
realatively fine grained particles that are carried in suspension
what is a bed load
sediment that is transported allong the bottom of the channel by rolling or bouncing
what is the equation for stream power
=PGQS
what is the effect of base level fall
if base level fall occurs relatively slowly the channel will increase its sinuosity insteady of incising
what is the defenition of mass movement
collective term forall gravitational or downsloping movements of weathered rock debris
what are the 2 categories of mass movement
slow continous movement
rapid episodic moevement
what is the characteristics of a slow continous mass movement
slopes are typically convex up and smooth, creep and diffusion, non accelerating
what is the characteristics of a rapid episodic mass movement
not diffusive hillslope erosion. usually more damaging that diffusion. Humocky topography. flows and slides
why are debris flows so destructive
move rapidly 10-25 m/sec. density of debris flow is greater than water due to equation and can transport large rocks. vally bottoms or human structures are buried as the flow stops
what are earth flows
are unusually slow and are large in areul extent. dont follow pre existing drainage. deep seated in that they affect a significant thickness of a hillslope
what is slump
are rotational slides, having curved failure surfaces. typically occur in thik homogenous cohesive sediments, example is mud rich part of franciscan complex
what are slides
type of mass wasting consisting of rocks or masses of weathered rock moving downhill allong discrete shear surfaces
