earth sci Flashcards
exam Q2
-a process by which rocks are broken into smaller fragments chemically or physically
-refers to the process of disintegration and decomposition of rocks
weathering
occurs in regions where temperature fluctuates above and below freezing point, resulting to freeze thaw cycle
frost wedging
breaking down of rocks into pieces without any change in its composition
physical/mechanical weathering
describes the process of chemicals in rainwater making changes to the minerals in a rock
chemical weathering
Types of Physical Weathering
frost wedging, thermal stress, salt crystal growth, abrasion, biological activities anthropogenic activite
wearing away of rocks by constant collision of loose particles
abrasion
force exerted by salt crystal that formed as water evaporates from pore spaces or cracks in rocks can cause the rock to fall apart
salt crystal growth
rocks react to temperature changes during the day or between seasons by expanding or contracting
thermal stress
plants and animals as agents of mechanical weathering
biological activities
human activities can lead to weathering of rocks through mining, road and dam construction, deforestation etc.
anthropogenic activities
Types of Chemical reactions
dissolution, carbonation, hydrolysis, oxidation, biological activities
process by which a mineral dissolves in water
-produce ions, but no minerals, and are reversible if the solvent is removed, these rocks produces caves, sinkholes, sinking streams and large springs, creating a landscape known as karst
dissolution
the reaction between calcite and weak acids in rainwater and acids in ground water
carbonation
it is the response of oxygen with minerals. if the iron oxidizes the minerals in rocks decomposes example rusting
oxidation
hydro
water
lysis
to loosen or dissolve
every atom is physically bonded to its neighbors in some way. if heat energy is supplied to one part of a solid, the atoms vibrate faster.
thermal vibrations
occurs when water combines with the substance to form a new types of substances which are softer than the original rock type
hydrolysis
the process by which heat energy is transmitted through collisions between neighboring atoms or molecules
conduction
plants and animals release acid forming chemicals that cause weathering and contribute to the breaking down of rocks and landforms
biological activities
heat flows from center of the earth to the surface
conduction, convection, radiation
the fluid above a hot surface expands, becomes __________ and__________
less dense and rises
when a fluid, such as air or a liquid is heated and then travels away from the source, it carries the thermal energy along
convection
the magma drive plate tectonics
convection currents
two types of energy source of the earth
internal, external source
generates from the emission of electromagnetic waves
thermal radiation
occurs through a vacuum or any transparent medium (either solid or fluid)
radiation
energy source on earth
internal source, external source
coming from within the earth
internal source
non-earth generated
external source
generated during earth formation
primordial heat
the __________ energy accumulated by dissipation in a planet during its first few million years of evolution
internal heat
conversion of kinetic energy of smaller planetary objects into heat as they called on accretion
accretion energy
as something compresses, heat is generated (adiabatic heating)
adiabatic compression
_________________ in which no heat is added to or subtracted from the air
compression
heat from the earth’s core setting of iron (fe) to center of earth converts the potential energy of iron to heat energy
core formation heat
in early solar system have isotopes such as AI26, CI36, Fe60, with half lives of approximately 0.3 Ma
decay of short lived radio isotopes
main source of internal heat come from the ______ from its interior
produced naturally occurring isotopes
which the spontaneous breakdown of an atomic nucleus causes the release of energy and matter from the nucleus
radioactive decay
this process of radioactive decay which emits_____ as one of the products prevent the earth from completely cooling off
heat energy
due to____ in ____ and presence of heavier materials towards the earth’s center, the _____________ of earth’s layers also ___________
increase, pressure, density, increases
is a geological process that was formed, originated, and located below the surface of the earth. It involves geological activities such as tectonic movements, metamorphism, seismic activities and magmatism
endogenic process
how does magma formed?
partial melting of mantle rocks
takes place because rocks are not pure materials
partial melting
two main mechanism through which rocks melt
decompression, flux melting
takes place within earth when a body of rock is held at approximately the same temperature but the pressure is reduced this happens because the rock is being moved toward the surface
decompression melting
happens if a rock is close to its melting point and some water or carbon dioxide is added to the rock, the melting temperature is reduced and partial melting starts
flux melting
magma escaped in two forms:
intrusion, extrusion
magma that moves up into a volcano without erupting (magma does not get out)
intrusion
refers to all sorts of igneous geological activities taking place below the earth’s surface
plutonism
the process of crystallization takes place inside the crust, the magmatic rocks produced are called _______
plutonites
an eruption of magmatic materials that causes land formation on the surface of the earth causes the formation of volcanoes
extrusion
is used to describe all geological phenomena that occurs on the natural terrestrial surface, such as the creation of volcanoes and hot springs
volcanism
molten rocks in form of lava that undergoes the process of crystallization on the natural terrestrial surface gives birth to rock formation known as_______
volcanites
the process where a pre existing rock transform into another form of rocks
metamorphism
the increase in temperature and pressure and change of the chemical environment can_____________________ of the rock while remaining solid all the while.
change the minerals composition and crystalline textures
the rocks adjust to the new temperature causing their atom and ions to recrystallize and form new arrangements thereby creating new minerals assemblages. during recrystallization, new crystals grow larger than the crystals in the original rock
burial metamorphism
factors involved in metamorphism
temperature, pressure
types of pressures
vertical stress or confining pressure, directed or differential pressure
the rate at which temperature increases with depth in the earth’s crust
geothermal gradient
is the same in all directions and makes the rocks to fracture or deform
vertical stress
is imposed by a force in a particular direction. differential pressure is dominant at convergent boundaries where plates move towards each other and collide thus exerting force and cause rocks to deform
directed or differential pressure
shale with clay minerals
sedimentary rock
is a set of flat or wavy parallel cleavage planes produced by deformation under directed pressures
foliation
state with mica minerals
metamorphic rock
schist with garnet minerals
metamorphism rock
surrounding rocks are exposed to heat coming from magma intrusion within the layers of the rocks
contact metamorphism
shale with bedding
sedimentary rock
schist with larger foliation
metamorphic rock
state with foliation
metamorphic rock
within the continental crust, the confining and directing pressures exerted by some tectonic forces onto rock formations cause new alignment of minerals (foliation) during recrystallization
regional metamorphism
marble, quartzite, and other granoblastic rocks with large visible crystals of minerals may be formed through ______________
contact metamorphism
rocks possible responses to stress
elastic deformation, plastic deformation, fracture
upward folds
anticlines
types of stresses
compressional stress, tensional stress, shear stress
gently dipping bends in horizontal rock layers
monoclines
squeezes rocks together, happens at convergent plat boundaries, two tectonic plates are plowing in each other, power earthquakes
compressional stress
stretches and pulls rock apart, occurs along divergent plate boundaries, two tectonic plate are tearing away from one another
tensional stress
three major types of rock folding
monoclines, anticlines, synclines
downward folds
synclines
example of tensional stress
mid atlantic ridge, rifting in eastern africa
causes minerals to split in a formation known as cleavage
shearing stress
explained how the convection currents in the Earth’s interior make the seafloor spread.
Harry Hess
_____________ carry heat from the______________ in the mantle and core towards the lithosphere
convection current, molten materials
a device that bounces sound waves off underwater objects and then record the echoes of these sound waves, many people believed that the ocean floor was a completely a flat surface
sonar
These 2 causes seafloor spreading
Convection current , molten materials
core samples from the ocean floor show that older rocks are found farther from the ridge; youngest rocks are in the mid-ocean ridge
- Evidence from drilling sample
