Science 7 Flashcards
who published the continental drift theory
Alfred Wegner
what is the one big super continent called
Pangea
what is the northern continent that Pangea split into called
Laurasia
what is the southern continent that Pangea split into called
Gondwana
what are the seven plates that make up most of the continents and the Pacific Ocean
African Plate
Antarctic Plate
Eurasian Plate
Australian Plate
North American Plate
Pacific Plate
South American Plate
who propsed Sea floor spreading
Harry Hess
what are mantle convention currents
warm mantle currents drive and carry plates of lithosphere along a like a conveyor belt
what is Ridge push
newly-formed plates at oceanic ridges are warm, and so have a higher elevation at the oceanic ridge than the colder, more dense plate material further away
what is slab pull
older, colder plates sink at subduction zones, because as they cool, they become more dense than the underlying mantle.
how are convection currents involved in the movement of tectonic plates
The tectonic plates are dragged along by the friction between the magma and the tectonic plate as the hotter magma in the asthenosphere rises (less dense), flows under the tectonic plate, cools then sinks (more dense).
what are the different types of crusts
Oceanic Crust Continental Crust
what are the three types of plate boundaries
Divergent Boundaries
Convergent Boundaries
Transform Boundaries
What are divergent boundaries
Diverging boundaries are where tectonic plates are moving apart from each other in opposite directions.
what are convergent boundaries
When two plates come together
what are transform boundaries
Transform boundaries are places where plates slide sideways past each other
what is the core made of
The core is mostly made up of nickel and iron.
what is the inner core made of
The inner core is solid and the outer core is liquid.
what is the mantle
Thickest Layer of the Earth
Semi-Solid / Semi-Liquid
what is crust
Outer Layer of the earth
Thinnest Layer
Solid
what is a rock
A solid
Naturally occurring
Is made up of minerals or mineral like matter
Some rocks are composed of just one mineral. Most rocks are a solid mixture of several minerals
what is a mineral
A mineral is a solid substance that is the same
how are rocks made
Rocks are made by processes on and in the earth that constantly cycle materials. This is known as the rock cycle.
igneous rock
(formed from red hot melted rock
sedimentary rock
(formed when small pieces of rock wear off and become stuck together),
metamorphic rock
(rocks that are changed by heat and pressure).
weathering
– breakdown of rock into small pieces
what is outer core
Liquid layer of the Earth
Molten Iron and Nickel
Second hottest layer
what is inner core
Hottest layer of the Earth
Solid – should be a liquid but so much pressure that it becomes solid
what is the lithosphere
Functional section of the Earth that includes the crust and a small section of the upper mantle
It contains the tectonic plates
what is Asthenosphere
A functional semi-liquid layer of the mantle
This section is where the convection currents occur
what is magetic striping
From samples of rock taken on the seafloor it can also be seen that rock samples take the same distance from ridges have similar properties including magnetic properties. There are therefore stipes of magnetically similar rock again support the plate tectonic theory
