3.3 Geosphere Flashcards
Geosphere is also known as “____________”
Skeleton of our Planet
- is the solid Earth that includes the continental and ocean crust as well as various layers of Earth’s interior
- it is not static or unchanging
Geosphere
- the rocky outermost layer
- exposed to atmosphere
- thinnest layer (70km)
- made of solid rocks and minerals
- varies in temperature
Crust
what are the abundant elements of the crust?
oxygen, silicon, aluminum
- thicker but less dense
- made mostly of granite
- 1/3rd of Earth’s surface
continental crust
what are the abundant elements of the continental crust?
SiAl: silicate and aluminum
- thinner but denser
- made mostly of basalt
- two third of Earth’s surface
Oceanic Crust
what are the abundant elements of the oceanic crust?
SiMa: silicate and magnesium
- middle layer
- lies between core and crust
- 2,900km thick
- 84% of Earth’s volume
mantle
what are the characteristics of the Upper Mantle?
- lithosphere and asthenosphere
- rigid/solid
- some regions are malleable, contributing to tectonic activity
- 650km thick
what are the characteristics of the Lower Mantle?
- hotter and denser than upper
- less ductile due to high pressure
- 2,250km thick
- volume of Earth at 54%
- rocky part of the Earth in the Crust and Solid Upper Mantle
- 100km thick
Lithosphere
Studied the motion of the lithosphere over a molten layer.
Joseph Barrell (1914)
- 2,200km thick
- mostly composed of liquid iron and nickel
- temperature ranges 4,500-5,500 degrees celsius
- very low viscosity; easily deformed and malleable materials
- site of violent convection which creates and sustains Earth’s magnetic field (protects us from solar flairs)
Outer Core
- hot dense ball of mostly iron
- 1,230km thick
- 5,200 degrees celsius
- pressure nearly 3.6million atm
- iron and nickel (solid state)
- intense pressure and density result in its solid state
Inner Core
between the crust and upper mantle
Mohorovicic Discontinuity
between upper mantle and lower mantle
Repetti Discontinuity
between the lower mantle and outer core
Gutenberg Discontinuity
between outer and inner core
Lehmann Discontinuity
What are the chemical properties of Crust?
avg. composition:
- 47% oxygen
- 27% silicon
- 8% aluminum
- <11% Fe, Ca, Mg, K, Na
What are the chemical properties of Mantle?
silicate rocks rich in iron and magnesium
What are the chemical properties of the Core?
iron and nickel
What are the physical properties of Lithosphere?
brittle solid
What are the physical properties of Asthenosphere?
ductile solid
What are the physical properties of the Outer Core?
liquid
What are the physical properties of the Inner Core?
rigid solid
Rocks formed by years and years of sediment compacting together and becoming hard.
sedimentary
Rocks formed by great heat and pressure. often made from other types of rock combined
Metamorphic
Rocks formed by volcanoes. when a volcano erupts, it spews out hot molten rock called magma or lava
Igneous
cool slowly
intrusive or plutonic
cools quickly
extrusive or volcanic
Naturally occurring inorganic solid materials with definite chemical composition and ordered atomic arrangement.
minerals
Physical property of a rock that is most obvious, least diagnostic?
color
Physical property of a rock that is strength of the chemical bonds, using a Mohs scale?
hardness
Physical property of a rock that is the color of the mineral in its powdered form?
streak
Physical property of a rock that consistently breaks along planes, break smoothly along specific internal planes?
cleavage
Physical property of a rock that breaks along random irregular surfaces?
fracture
Physical property of a rock that forms a definite structure that has a specific crystal form
crystalline structure
Physical property of a rock that is the appearance when light is reflected from its surface?
luster
Physical property of a rock that is the outward appearance of the specific crystal form, ideal shape?
crystal habit
What kind of luster is sparkly?
adamantine
What kind of luster is dull and clay-like?
earthy
What kind of luster is pearl-like?
pearly
What kind of luster is like resins, such as tree sap?
resinous
What kind of luster is soft-looking with long fibers?
silky
What kind of luster is glassy?
lustreous
Physical processes that create and modify landforms on the surface of the Earth.
Geomorphic Processes
What are the four types of exogenic processes?
weathering, mass movements, erosion, and deposition
breaking up of large rocks into smaller fragments — without changing the rock’s mineral composition
Ex. frost wedging, insolation or thermal stress, unloading and expansion
Physical Weathering
decomposes rocks through chemical change
Ex. carbonation and solution, hydrolosis, oxidation (rust)
Chemical Weathering
Animal action - burrowing animals (rat, ant, snake dug out earth)
Plant action - plant roots break up rocks when they grow between joints of rock.
Human action - construction, mining work
Biological Weathering
mass movement of rocks, soil, and regolith driven by gravity, water, over steepening of slopes, removal of anchoring vegetation and ground vibration
Mass Wasting
examples of rapid mass movements
flow, topple, slump
examples of slow mass movements
slide, creep, fall
Process of transporting weathered sediments by agents of erosion to different places
erosion
Aggradation or accumulation of weathered and/or eroded sediments to create different landforms.
Ex. in the rivers, sand dunes, talus apron
deposition
internal geological processes
Endogenic
heat energy and plate tectonics
driving force
involves “constructive forces” for large scale landform building and transforming processes
Endogenic
when rocks are subjected to stresses, they begin to deform (when convergence happens)
Endogenous processes
is stress that decreases the volume of a material
compression
stress that pulls material apart
tension
stress that causes a material to twist
shear
- two forces push towards each other from opposite sides, the rock layers will bend into folds
- anticline (upward arch), syncline (downward arch), limbs (sides)
folding
anticline:
syncline:
limbs:
upward arch, downward arch, sides
fracturing and displacement of more brittle rocks along a fault plane either caused by tension or rock compression
faulting
- a theory that explained how continents shift position on Earth’s surface
- also explained why look-alike animal and plant fossils, and similar rock formations, are found on different continents
Continental Drift Theory
continents were all originally part of a huge landmass “______”, that was surrounded by a single ocean, “____________”
Pangaea, Panthalassa
occurs when plates slide apart from each other or move away
divergence
when two plates slide toward each other, causes subduction of the heavier or denser plate (trenches, volcanic arcs, island arcs, mountain ranges, plateaus)
convergence
plates slide horizontally past one another and move separately in opposite direction, generally defined by shallow earthquakes (e.g. San Andreas Fault)
transform
study of the processes that deform Earth’s crust
tectonics
plates that move around on top of the asthenosphere, cause large-scale movements of the earth’s lithosphere
tectonic plates
- uplifting or warping of large crust
- this creates continents, plateaus and caused by vertical movements from the earth’s center
- Ex. Submerged forests and valleys, uplifted landforms
Epeirogenic Processes (vertical)
eruption of molten rock onto Earth’s surface (pacific ring of fire)
Volcanism
caused by seismic waves, being the most destructive and dangerous. The severity depends on factors such as magnitude, distance from the epicenter, and physical properties of soil and rocks.
Ground shaking
follow curved paths through the interior of the Earth
seismic waves
- the tearing of ground’s surface
- can cause ground deformations and severe damage to infrastructures
Ground rupture
- when loosely packed, water-saturate soil loses strength and stiffiness
- structures may sink and be surrounded by liquefied soil
liquefaction
downward movement of soil, rocks, and debris due to ground shaking and gravity
earthquake-induced landslide
- mixtures of rocks and glass particles expelled from volcanic eruption
- can cause danger in health (respiratory system)
- Mt. Pinatubo eruption on June 15, 1991
Volcanic ash and Tephra
hot, fast-moving clouds of fragmented volcanic particles, gases, and ashes that travel rapidly down a volcanic slope
Pyroclastic Density Current (PDC)
dense, coarse, fragments that move along the ground, ground-hugging, basal flow
Pyroclastic flow
less dense, more mobile cloud of ash that moves above the pyroclastic flow
Pyroclastic surge
Indonesian term for volcanic mudflow composed of slurry water, rock fragments, and pyroclastic materials
Lahar