what are the 5 layers of the earth and their lengths
inner core,1216 km-outer core,2266 km -mantel,2867 km-crust, 5 to 7 km moho
what is the continental crust mad out of?
what is the oceanic crust made out of?
what kind of heat transfer is the sun warming the earth?
what are mid ocean ridjes?
a continuos chain of vocanos on the ocean floor that erupt molten material pushing out the old rock and creating the process called sea floor spreading
describe sea floor spreading
In the mid ocean ridjes their are rift valleys that erupt with molten material. The molten material comes out and hardens pushing away the older rocks (pushing out) creating a process called sea floor spreading. The iron particles are pulled magnetically to the north or south depending on if the earth's magnetic feild is "reversed" or "normal" the iron particles create a magnetic memory. You can only see the difference of the "magnetic stripes" with a special microscope but if you look at them through it you will see that is is symetricall on each side of the underwater volcano this creates magnetic smetry.
continental - oceanic convergent what is created
when they colide it makes a trench or subduction zone it is caused when the ocean floor sinks beneth the mantel. The ocean floor sinks and warms and creates lava wich will come up and make volcanos on the sides of the continental crust.
a device that scientists use to help map the ocean floor is
the chain of mountins that extends into all earths oceans is the......
mid ocean ridje
an american geologist who found a lot of evedence that supported wagner
when a lot of evedence that supported wagners theory of the continental drift was found
it Harry hass proposed a radical idea of how land was created and moved. his theory was called __________a____________. It stated that new ocean crust is formed at ___________b________ and destroyed at _______c________________
a- sea floor spreading
b-mid ocean ridjes
why does the magma erupt from the underwater volcanos
the magma is much less dence and hotter than the sorrounding rock so it is forced twards the surface alond the ocean ridje.
MID OCEAN RIDJES
are the long, continuos, mountain ranges that run through all of tha oceans of the earth. there are 80000 KM long and as tall as 3 KM. Ice land is an example of where a mid ocean ridje comes above the ocean.
Narrow elongated depressions in the seafloor. The can be thousands of Kilometers long an many kilometers deep.
how deep is the deepest trench
3 types of evedence of sea foor spreading
evedence from molten material, Evedence from magnetic striped, evedence from drillings.
EVEDENCE FROM MOLTIN MATERIAL
an Important clue about what is happeneing in the oceans. the youngest rocks are found near the mid-ocean ridjes. The youngest rocks are found at the edjes of the ocean(near continents)
oldest land rock
4 billion years
oldest ocean rock
180 milllion years
ocean floor thickness
thin by the ridjes thick by the shores
EVEDENCE FROM MAGNETIC STRIPES
PALEOMAGNETISM- is tha history of earths magnetic feild. when there is a change in the flow of the outer core of the earth the magnetic feild switches from north to south and vice verca. Scientists have seen evedence of this in magnetic (acts like a little compass) deposits in the ocean floor.
EVEDENCE FROM DRILLING SAMPLES
in 1960's scientists found eedence that new maerial is indeed erupting alond the mid ocean ridjes. they saw pillow lave.
what date and who made a hypothoss that " all the continents where once joined together in a single lad mass and have since drifted apart." this idea became known as __________a______
______A _________ the super continent means __B____________
b -all lands
they say the PAngea existe around ____ years ago
when did alfread wagner publish his book and what was it called
it was called -the origin of continents and oceans
3 types of evedence alfread wagner had to support his theory
-evedence from ocean features
-evedence from fossils
-evedence from climate
EVEDENCE FROM LAND FEATURES
Examples of this are mountin ranges that match on both sides of the ocean.coal deposits that match in europe and north america
EVEDEDCE FROM FOSSILS
examples of this are Glossopteris, mesossaurus and lystosarus. its when their are identical fossils on the edjes of different comtinents
EVEDENCE FROM CLIMATE
Examples of this enclude Tropical plant fossils found on SPITS BURGEN an island in the artic ocean. and glacial deposits in south africa
if alfread wafner had soo much evedence why did other scientists reject his theory?
HE couldn't explain how or why the continents had moved.
how did most scientists in the 1910's think mountins formed and what did wagner say about that?
they said earth was once a liguid and when it coold the rock wrinkled and made mountins
wagner said then their would be mountins all over. he said that is hapened when earths continents colided.
What 2 main types of evedence do geologists use to learn about earths interior?
Direct evedence from drillings
inderect evedence of seismic waves.
DIRECT EVEDENCE FRO DRILLINGS
rocks from inside earth give geologists clues about earths structure. Geologists use these rocks to make infrences about conditions deep inside the earth.
GEOOGISTS have drilled hols as deep as ___
INDERECT EVEDENCE OF SEISMIC WAVES
THis is a mathod that scientists use to study the earths interior. they study seismic waves to learn about the earths interior the speed and the path they take revel the structure of the planet.
TEMPERATURE OF THE INNER EARTH
the first 20 m the temp is cool then every 40 m you go down, the temp increases by 1 degre
how does the pressure change as you go deeper into the earth? why?
it goes up because of the weight of the rocks above.
includes both dry land and ocean floor ( continental annd oceanic)
All life as we know it exists where?
in the frist 10 m of the crust.
continental crust = how thick (a)
the oceanic crust = how thick (b)
a ) up to 70 km
b) 8-10 km