Quiz 2 Flashcards
drives convection, therefore plate tectonics
heat inside earth
things tht control/drive plate tectonics
- convection (main driving force)
- ridge push
- slab pull
- slab suction
went to challenger deep in trieste
don walsh and jacques picard
measures how deep water is
bathymetry
how to measure bathymetry/depth
- rock and rope
- single beam sonar
- multi bean sonar
- satellite altimetry (doesnt measure depth)
single depth measurement
sounding
produced first full map showing sea floor in 1977
marie tharp and bruce heezen
average depth of ocean
12500 ft
average depth of land
2860 ft
largest % of earth’s surface occupied by
ocean basin floors
florida coastline is modified by
strong florida current
oregon coast is modified by
large river and scrapping of shelves
texas coastline is modified by
salt domes
what evidence do turbidites leave behind in rock record
graded beds
:greater sized rocks at bottom with finer sized rocks at top all deposited from one event
what triggers turbidites
:turbid flows of sediment
triggered by: earthquakes and hurricanes
- emit crystals of metal sulfides
- more iron
black smokers
- emit crystals of metal sulfides
- more aluminum
white smokers
volcanoes on seafloor
were at one point above sealevel and active but got too far from magma and sunk below sea level
Guyots
mountains
at one point were above sealevel
seamounts
name 7 ocean sediments
- clay
- silt
- sand
- granules
- pebbles
- cobbles
- boulders
sediment that comes from land
terrigenous sediments
sediments that come from space
cosmogenous sediments
calcium carbonate “calcite”
CaCO3
organisms of carbonate biogenous sediments
- foraminiferan (forams)
2. coccolithophores
depth at where CaCO3 skeletons are dissolved by acidic waters with CO2
Carbonate Compensation Depth (CCD)
average depth of CCD
4500 meters
silica
SiO2
organisms of silicious biogenous sediments
- radiolarians
2. diatoms
organisms of hydrogenous sediments
- manganese nodules
- hydrothermal vents
- oolites (made of CaCO3)
current velocity and sedimentation
the faster the current –> the less the sedimentation comes to rest
the slower the current –> the more the sedimentation comes to rest
study of tracks, trails and burrows
**tells us about fossilized behavior
ichnology
How we sample the sea floor
- Clam shell scoop
- short cores
- piston cores
- drilling
- divers
- remote sensing
- submarines and ROVs
tiny critters in sediment that move around in sample of sea floor, destroying it
meiofauna
characteristics of water
- Polar
- Adhesive
- Cohesive
- Solid is less dense than liquid
- High heat capacity
- exists as solid, liquid, gas at 0 C at earths surface
- High latent heat
- Universal solvent
- about 1m/yr evaporates from oceans
energy produced by vibration of atoms or molecules
*measures how many atoms or molecules are vibrating
heat
measure of how rapidly the molecules of a substance are vibrating
temperature
energy necessary to raise 1 gram of water 1 degree celsius
calorie
-measure of heat required to raise the temp of 1 gram of a substance by 1 C
heat capacity
***heat capacity and calorie are same only w/ water
water reaches its max density at
4 degrees celsius
…decreases (lowers) temp for freezing
salinity
density and temp of seawater (characteristics)
increase temp –> decrease density
increase salinity of water –> increase density
Depth of shelf slope break
140 meter depth
