unit 2- geology Flashcards
what is the crust of the earth
the outer layer of the earth made of soild rock
what is the mantle of the earth
the second layer of the earth also made of solid rock but can flow slowly due to heat and pressure
what is the outer core of the earth
the third layer if the earth made of liquid iron and nickel
what is the inner core of the earth
the fourth and most inner part of the earth made of solid iron and nickel it is over 5000 degrees celcius
how old is the earth
4.5 billion years old
what are plate tectonics
the earths crust is split into a series of plates that are constantly moving
what is a large scale map
a map that covers a smaller area but with more detail
what is a small scale map
a map that covers a larger area but with less detail
what is a tsunami
a large sea wave caused by under-water earthquakes
continental drift
theory that the continents have drifted apart over millions of years and used to be one supercontinent called pangaea
who created the pangaea theory
a german scientist named alfred wagner
when was the cenozoic era
current time- 66 million years ago
when was the mesozoic era
66 million year ago- 245million years ago
when was the paleozoic era
245 million years ago- 570 millions year ago
when was the precambrian era
570 million years ago- 4600 million years ago
how do earthquakes happen
when two plates get caught on eachother and eventually slip it causes an earthquake
how do volcanoes happen
when two plates are pulled apart from eachother it allows magma to flow through
what is a divergent boundry
new crust is generated when the plates pull away from eachother and magma goes through and hardens
what is a covergent boundry
where one plate in shoved under another and mountains are formed
what is a transform boundry
when two plates rub against eachother and can get stuck for long periods of time building up tension
what are convection currents
circular motion currents caused by difference in temperature
what is subduction
when a tectonic plate subducts under another it is pushed under and goes into the mantle where it is melted away
