Exam 1 Flashcards
Geology
scientific study of the earth
Origin of the Earth
Planetary accretion (pieces of debris smashed together)
Origin of Solar System
solar nebula hypothesis (gas cloud, nuclear fusion)
Layered earth
Planetary differation (melted earth ball seperates layers into density)
Age of Earth
4.5 billion years
Age of Universe
13.8 billion years
Layers of Earth
crust, mantle, outer & inner core
Crust consists of
continental and oceanic
Oceanic crust
thin, denser, basalt, less silica
Continental crust
thick, less dense, granite, high silica
8 elements of earth
oxygen, sodium, magnesium, potassium, calcium, iron, aluminum, SILICON
Lithosphere =
brittle upper mantle + crust
convecting mantle =
athenosphere
lower solid mantle
mesosphere
why is earth older than oceanic crust?
subduction
Pangea (continental drift) and evidence?
Alfred Wegner, same species and rock types/structures
Sonar=
goods maps of the seafloor
Magnetometer=
magnetic field reversals recorded in oceanic crust
Sea floor spreading
Harry Hess, mantle convection and slab pull
Paleomagnetisms
seafloor records reversals of Earths magnetic field through previous lava now hardened igneous rock
90% of earths crust is
silicon and oxygen
Minerals =
naturally occuring, inorganic, solid, orderly crystalline structure, definition composition
Ionic =
one atom gives electrons to another, opposites attract
covalent =
atoms share electrons
mineral properties =
color, luster, streak, hardness, cleavage, crystal form, specific gravity, magnetism, radioactivity, reactivity w/ acid
Mineral groups other than Silicates =
sulfates, carbonates, sulfides, halides, phosphate
Rock cycle =
leave open
Rock =
a solid aggregate of minerals & possible some other non-minerals
3 ways to create magma (melt)
1: add water (flux melting), 2: reduce pressure (decrompression melting), 3: add heat
“ignis” means what in what language?
fire in latin
Magma vs Lava
Magma = parent material of igneous (molted once cooled), melting rocks INSIDE of earth
Lava = Magma at the SURFACE
texture =
cooling of magma/lava to form igneous rocks
Different types of textures =
aphanitic, phaneritic, porphyritic, glassy, frothy, pyroclastic
which is fine-grained and which is coarse-grained?
fine-grained=aphanitic
coarse-grained=phaneritic
intrusive =
slow cooling inside earth, phaneritic, never erupted
map of seafloor by
Marie Tharp & Bruce Heezen
Wilson cycle stages =
Embryonic-East Africa ^
Juvenile-Red Sea <->
Mature- MOR <->
Declining-Pacific -><-
Terminal-Mediterranean
Suturing-Himilayas
Iceland sits on what?
MOR and a hotspot
What drives plate tectonics?
convection, plate density, and slab pull
island/arcs are formed by
subduction
island/chains are formed by
hotspots
transform faults
offset spreading at MOR, shallow earthquakes, plate boundary
fracture zones
extensions of transform faults, no earthquakes, within a plate
Hotspots =
point sources of magma, remain in fixed spots for long periods of time, oceanic AND continental
how hotspots created
1: heat rises from unusally hot zones
2: heat melts tectionic plate
3: magma rises to volcano
4: plate moves over hotspot
5: hotspot melts new spot
earthquakes that are deep and shallow are found where?
deep= ONLY convergent
shallow = all
which is the oldest volcano in Hawaii?
Kohala
extrusive volcano=
fast cooling on surface erupted, aphanitic
Glassy finished come from
super fast cooling
Frothy finishes come from
erupted with lots of gas and cooled quickly
Igneous Rock Composition and types=
magma chamber processes, age, and composition
-felsic, intermediate, mafic, ultramafic
color FIMU
light —–> dark
Silica content FIMU
(increasing silica) <——-
viscosity =
stickiness, resistance to flow
Low vescosity= water, high viscosity= peanut butter
what determines the explosiveness of an eruption?
viscosity (temp & composition), gas content
