sio midterm

which planet lie within the habitable zone of our solar system?

earth and mars

evidence that the south america and african continents were once joined includes

matching fossil distributions

at the seafloor, the rate of geothermal heat flow is greatest

along mid-ocean ridges

the pillow basalts in the photo below most likely formed

underwater at a mid-ocean ridge

2 competing views of the universe

Geocentric(\~150 CE) - earth center of uni

Heliocentric (1500 years later) - earth/planets/stars circle the sun

star definition

immense sphere of incandescent gas, mostly hydrogen (H) with some Helium (He), held together by gravity. Almost all stars are orbited by planets that have coalesced from a disk-shaped “nebula” or gas and dust

galaxy defintion

immense groupings of star (100s of billions)

universe definition

immense grouping of galaxies (100s of billions)

Why is the solar system made of planets and moons?

Nebular theory of solar system formation

Terrestrial planets

mercury, venus

habitable zone

earth, mars

gas giants

jupitar, saturn

ice giants

uranus, neptune

mercury

atmosphere: none

temperature: -180-430 C

surface water: none

venus

atmosphere:50x thicker than earth

temperature: 470 C (melts lead)

surface water: none

earth

atmosphere: earthlike

temperature: cool/warm

surface water: yes, liquid

mars

atmosphere: thin

temperature: cold

surface water: yes, ice

earth is comprised of 4 elements

oxygen (30%)

silicon (15%)

magnesium (13%)

iron (35%)

layers of earth

crust (rocky, cool)

mantle (rocky, hot)

outer core (iron, hotter)

inner core (iron, really hot)

crustal material

oxygen, silicon, aluminum

mantle material

oxygen, silicon, magnesium

core material

iron

continental crust

light and thick

oceanic crust

dense and thin

lithosphere

rigid crust and mantle

asthenosphere

weak mantle

moho boundary

due to composition differences between crust and mantle

lithosphere/asthenosphere

boundary is due to rocks becoming weaker as temperature increases with depth

transition zone

boundaries are due to formation of new types of rocks under increasing pressure and temperature within the mantle

evidence for continental drift

fit of the continents

locations of past glaciations

distribution of climatic belts

distribution of fossils

matching geological units

Why against continental drift hypothesis?

Lacked plausible mechanism

breakthrough tech

SONAR (map seafloor bathymetry)

Seismic profiling

Continuously operating seismometers

Seafloor drilling

breakthrough results

discovery of ridges and trneches

sediment thickness increases away from ridges

earthquakes are located at ridges and trenches

heat flow from the mantle is concentrated at ridges

marine magnetic anomalies

Earth’s magnetic field changes polarity regularly

Crust is magnetized with polarity thats present when it formed

Pattern of crustal magnetization reveals the history of seafloor spreading

tectonic plate

a portion of earth’s lithosphere (rigid crust + rigid layer pf upper mantle) that moves as a single unit relative to other plates\\

global seismicity (earthquakes)

concentrated at plate boundaries because there must be a lot of stress on the (brittle) lithosphere at plate boundaries

divergent boundary

convergent boundary

→

transform boundary

→

Convection

less dense (warmer) material rises, more dense(cooler) material sinks to take its place

old covection idea

convection drives large scale mantle flow. plates move with the mantle. not wrong but too simplistic

Forces

contributing to tectonic plate motion

slab-pull

pulling the plate down behind it

ridge-push

pushing the plates apart

mantle-drag

dragging the plate from below

hot spot

region of concentrated volcanic activity

hot spot track

line of volcanoes that show history of crust moving over hot spotsC

what do continuous GPS stations track?

current crustal motion

rock

a naturally occurring solid that typically consists of one or more minerals arranged in an irregular pattern

mineral

a naturally occurring solid that has a crystalline structure ( where atoms are well ordered, like stacked oranges) and a consistent elemental composition

element

a species of atom with a fixed number of protons in the nucleus (ex hydrogen 1 proton, carbon 6 protons)

diamond

a form of crystalline carbon found naturally in kimberlite, volcanic rock formed deep in earth’s crust

diamond (crystal structure tetrahdranal) and graphite (crystal structure is hexagonal) is a mineral made of what

carbon

95% earth’s crust is made of 5 elemets

oxygen (46%)

Silicon (28%)

aluminum (11%)

iron (6%)

Magnesium (4%)

rock classifications

metamorphic, igneous, sedimentary

igneous rock

rock made from the solidification of melt (molten rock)

3 typical locations of igneous rock formation

mid-ocean ridge, hot spot, subduction zone

pillow lava

igneous rock that we can see being created on the seafloor at a mid-ocean ridge

feisic

cooler magma (high silica)

mafic

hotter magma (low silica)

shield volcano (mauna kea)

formed from hotter lava that flows quickly (less viscous)

stratovolcano (mt. fuji or fuij-san)

formed from cooler lave that flows slowly (more viscous)a

mafic lava

low viscosity, easy flowing

pahoehoe

fast/hot

A’a

slower/cooler

felsic lava

high- viscosity, slow flowing, explosively erupting

felsic lava explosion

lava bombs and pumice

felsic lava

obsidian (fast-cooling rhyolite)

dikes

cuts across layers

sills

pushes between layers

broad intrusions

batholiths

small intrusion

pluton

sedimentary rock

rock formed at or near the surface of the earth in one of several ways, typically at low temperatures

lithification

compaction and cementation of sediments to form sedimentary rock

depositional environment

place and/or conditions where sediments collect

angular clasts

breccia

river gravel (river)

conglomerate

beach/dune sand (desert/river)

sandstone

mud (estuary)

shale/mudstone

corals (shallow marine)

limestone

plankton shells (deep marine)

chalk

plants (marsh/estuary)

coal

metamorphic rock

rock that forms when a pre-existing rock undergoes changes due to exposure to high pressures, high temperatures, high shear stresses and/or fluids deep

what temp metamorphism occurs?

at 200 degrees celsius and hotter

why do we use metamorphic rock (marble) for buildings rather than its protholithic sedimentary rock( limestone)?

marble is much more durable than limestone

4 products of volcanic eruptions

lava, rock, ash, gas

basaltic lava

low viscosity and can flow long distances

Andesitic lava

too viscous to flow far and tends to break up as it flows

felsic lava

so viscous that it may pile up in a dome-shaped mass

eruption

a release of pressure from a magma chamber inside earth

what’s inside a pressurized magma chamber?

molton rock containing dissolving gas

hawaiian fountian / lava fountains (small)

lava

stombolian / rock fountains (small)

rock

vulcanian / lava/rock fountains(medium)

lava, rock, ash

plinean

rock, ash, gas

first type of eruption style (balloon)

pressure release: small and slow

eruption type: effusive

second type of eruption style (soda)

pressure release: large and fast

eruption type: explosive

what evidence do we have for properties of earth’s interiors?

asteroids → earth composition

lab experiments→ prop of earth material at depth

seismic waves → density and phase (solid/liquid) of material

pull of gravity → earth mass = density = relative amount of dense material (iron)

subduct

recycled back into the mantle, causing deep earthquakes

seafloor spreading

gradual movement of oceanic crust away from mid-ocean ridge