Active Earth

Question 1

what are the layers of the earth

Answer 1

inner core, outer core, mantle (and asthenosphere) and the crust.

Question 2

explain the rock cycle

Answer 2

igneous rocks are formed by cooled magma / lava.
metamorphic rocks are formed by heat and pressure applied to any type of rock.
sedimentary rocks are formed by compaction and cementation of sediment.
rocks can be destroyed by melting, weathering or erosion.

Question 3

how are rocks broken down in the rock cycle: physically

Answer 3

rocks are broken down physically by the agents of erosion such as wind water or ice as well as weathering.

Question 4

how are rocks broken down in the rock cycle: chemically

Answer 4

Chemical weathering changes the molecular structure of rocks and soil. For instance, carbon dioxide from the air or soil sometimes combines with water in a process called carbonation. This produces a weak acid, called carbonic acid, that can dissolve rock.
(national geographic)

Question 5

weathering

Answer 5

the breaking down or dissolving of rocks and minerals on the surface of Earth.
(national geographic)

Question 6

erosion

Answer 6

the geological process in which earthen materials are worn away and transported by natural forces such as wind or water
(national geographic)

Question 7

sedimentation

Answer 7

the deposition of rock fragments, soil, organic matter, or dissolved material that has been eroded
(national geographic)

Question 8

how are igneous rocks formed

Answer 8

from cooling molten rock

Question 9

extrusive igneous rock

Answer 9

extrusive igneous rocks are formed by the cooling of lava
extrusive rocks cool faster and therefore have smaller crystals

Question 10

intrusive igneous rock

Answer 10

intrusive igneous rock is formed by the cooling of magma
intrusive rocks have bigger crystals due to longer cooling times

Question 11

clastic sedimentary rock

Answer 11

rocks primarily made from smaller broken up rocks

Question 12

chemical sedimentary rock

Answer 12

formed by chemical precipitation dissolving minerals in the rock

Question 13

organic sedimentary rock

Answer 13

made from organic matter which contains carbon - hydrogen bonds

Question 14

how do sedimentary rocks tell as about different time periods

Answer 14

the sediment traps organic matter which can be used to date the matter around it. the sediment on the bottom is older than the sediment on the top.

Question 15

how are metamorphic rocks formed

Answer 15

when other rocks go under intense heat and pressure

Question 16

regional metamorphism

Answer 16

process that occurs over broad areas in the lithosphere, leading to the formation of metamorphic rocks with a flaky texture
(national geographic)

Question 17

contact metamorphism

Answer 17

a type of metamorphism where rock minerals and texture are changed, mainly by heat, due to contact with magma
(national geographic)

Question 18

continental drift

Answer 18

when tectonic plates move the continents

Question 19

fossil evidence

Answer 19

show how plants and animals as well as landscapes have evolved

Question 20

sea floor spreading

Answer 20

when two oceanic plates drift apart and the magma from the mantle below forms to make a new crust.

Question 21

magnetic striping

Answer 21

volcanic rocks, such as basalt, record the polarity of the Earth’s magnetic field. In other words, they contain crystals that point to magnetic north. When the basalt cools down from a molten state, those crystals are frozen in place and are all stuck pointing in the same direction. It’s like the rock has its own compass inside!

This means that rocks formed at different times have their magnetic crystals pointing in opposite directions. They can be used to determine the polarity of the magnetic field at the time they were formed!

The stripes are symmetrical on either side of the mid-ocean ridge.
The stripes are younger close to the ridge and older further away These features can only be explained by the theory of seafloor spreading!

(education perfect)

Question 22

sediment thickness

Answer 22

differences in the thickness of the crust around the world.

Question 23

converging plate boundries

Answer 23

this is were a subduction zone is formed one plate (often oceanic) has begun to sink under a bigger plate (often continental) as they were moving together. this causes lots of earth quakes and volcanoes.

Question 24

diverging plate boundaries

Answer 24

when two plates are moving away from each other eg. sea floor spreading.

Question 25

transform plate boundaries

Answer 25

when two plates move past each other in the opposite direction. causes earthquakes.