Earth's Formation and Structure

Question 1

big bang

Answer 1

current theory of the dispersal of matter and energy in the universe is the big bang

Question 2

oceanic crust

Answer 2

the denser crust under oceans

Question 3

SIMA

Answer 3

Silicon and magnesium, more dense

Question 4

SIAL

Answer 4

Less dense, silicon and aluminium

Question 5

Moho

Answer 5

The boundary between the crust and the mantle

Question 6

mantle

Answer 6

ultra basic in composition, olivine, pyroxene, rock under the mantle. Includes the lithosphere and asthenosphere.

Question 7

Lithosphere

Answer 7

solid outer layer, 100kms vertically, crust and the upper mantle

Question 8

Asthenosphere

Answer 8

denser, weaker layer beneath lithospheric mantle, high temperature and pressure makes this area molten and ductile (bendy)

Question 9

Inner core

Answer 9

solid Fe, inner core immense pressure (weight of the planet and atmosphere) prevents the iron form melting. Pressure and density are too much for a liquid state

Question 10

Outer core

Answer 10

liquid Ni and Fe, violent convection creates the earths magnetic field

Question 11

primary waves

Answer 11

faster and earlier than s waves. Can go through solids and liquids (rarefaction), travels like soundwaves, compression in the direction of energy, rarefaction through core. Shadow zone (103-150)

Question 12

secondary waves

Answer 12

don’t travel through liquids, perpendicular (right angles), stops through the outer core because it’s liquid (103-1030

Question 13

L waves

Answer 13

surface waves, back and forth

Question 14

shadow zones

Answer 14

area of the Earth’s surface where seismographs cannot detect an Earthquake after the waves have passed through the earth

Question 15

age of the earth

Answer 15

4.5 billion years ago

Question 16

meteorites

Answer 16

space debris that collide earth at great speeds (they burn up). Leftover from the solar system formation

Question 17

meteorites - evidence

Answer 17

scientists can measure isotopes in them provide a starting point to the earth’s composition. Compared with the oldest rock - found the chemical composition had already been altered. Crust has already formed on the Earth.

Question 18

magnetic fields

Answer 18

the magnetic field shields our earth form charged particles of solar wind. Only exists due to convection of the liquid outer Fe core

Question 19

direct drilling

Answer 19

Kola Borehole in Russia, 1262Km into the crust, only 1/3 through the crust

Question 20

Mine (deepest)

Answer 20

Mponeng Gold mine in south Africa. 4Km deep, so hot (60C) unbearable heat, ice and salt and fans

Question 21

Atmosphere

Answer 21

An atmosphere is the layers of gases surrounding a planet or other celestial body. Earth’s atmosphere is composed of about 78% nitrogen, 21% oxygen, and one percent other gases.

Question 22

Outgassing

Answer 22

Outgassing is the release of trapped gas or vapor that was previously dissolved, trapped, frozen, or absorbed in the solid. Outgassing can include sublimation and evaporation which are phase transitions of a substance into a gas, as well as desorption

Question 23

Troposphere

Answer 23

contains clouds, stroms and temperature, varies in thickness from 18km (at equator) to 8km (poles)
Temp decreases with altitude

Question 24

Statosphere

Answer 24

Commercial jet planes here to aviod weather systems, 30-40km thick and contains a layer within it with a high concentration of ozone. Gases become thinner but temperatures rise

Question 25

Ozone

Answer 25

a gas that absorbs much of the suns ultraviolet radiation

Question 26

Mesosphere

Answer 26

temperatures fall rapidly here as there is no water vapour, cloud, dust or ozone to absorb incoming radiation. Lowest temps roughly 90 deg C. Fastest winds, nearly 3000 km/hr

Question 27

Thermosphere

Answer 27

Temperatures rise rapidly with altitude reaching 1500 deg C plus, no definite upper limit it just fades into space

Question 28

Banded Iron Formations

Answer 28

Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. ... Banded iron formations are thought to have formed in sea water as the result of oxygen production by photosynthetic cyanobacteria.

Question 29

Hydrosphere

Answer 29

all the water on Earth's surface (oceans, seas, rivers and lakes). Many also include water contained within the Earth in this category

Question 30

Geosphere

Answer 30

The parts of the earth that are solid (not all rocks are in solid form)