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Flashcards in geography rocks and wheathering Deck (32)
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1

what exactly is rock?​

Rock is a mixture of minerals.​

2

what is a mineral

A mineral is a natural compound. It has a chemical name and a formula, like the compounds in science – but we use its geological name.​

3

what is geology

Geology is the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them. ​

4

describe sedimentary rocks

colourful
rough texture
forms in layers
reacts to weathering and erosion

5

describe igneous rocks

resistant to erosion and weather
hard
shines when polished

6

describe Metamorphic rocks

soft texture
resistant to weather
hard wearing

7

examples of sedimentary rock

sandstone chalk
limestone
shale

8

examples of igneous rock

obsidian volcanic ash
basalt granite

9

examples of metamorphic rock

marble schist
slate

10

how are sedimentary rocks formed

Sedimentary rocks are formed from sediments that have settled at the bottom of a lake, sea or ocean, and have been compressed over millions of years. ​

11

how are metamorphic rocks formed

Metamorphic rocks have been subjected to tremendous heat and/or pressure, causing them to change into another type of rock

12

how are igneous rocks formed

Igneous rocks are formed by magma cooling from the molten interior of the Earth.​

13

extrusive igneous rock

form from lava cooling at the surface of the Earth.

14

intrusive igneous rock

form from magma cooling underground, often relatively deep in the Earth.​

15

weathering

Weathering is the breaking down of a rock by the action of things in its environment e.g. heat, cold, rain, plants, chemicals etc. ​​

16

erosion

Erosion is the wearing away and removal of rock stone and soil by rivers waves wind and glaciers

17

Physical weathering

caused by the effects of changing temperature on rocks, causing the rock to break apart.

18

Freeze-thaw weathering (physical)

occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.

19

Exfoliation weathering (physical)

occurs as cracks develop parallel to the land surface a consequence of the reduction in pressure during uplift and erosion.

20

Solution weathering (chemical)

removal of rock in solution by acidic rainwater. In particular, limestone is weathered by rainwater containing dissolved CO2, (this process is sometimes called carbonation)

21

chemical weathering

caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic.

22

Hydrolysis weathering (chemical)

the breakdown of rock by acidic water to produce clay and soluble salts.

23

oxidation weathering (chemical)

the breakdown of rock by oxygen and water, often giving iron-rich rocks a rusty-coloured weathered surface.

24

Biological Weathering

Living organisms contribute to the weathering process

25

burrowing animals weathering ( biological)

(moles and rabbits) can also make cracks bigger.

26

Lichens, algae and mosses weathering (biological)

can produce weak acids which open cracks in rock and expose them to chemical and mechanical weathering.

27

Plants put down roots weathering (biological)

through joints or cracks in the rock in order to find moisture. As the plant grows, the roots gradually prize the rock apart.

28

rock cycle

The Earth's rocks do not stay the same forever
continually changing because of processes such as weathering, erosion and large earth movements.
The rocks are gradually recycled over millions of years.

29

What is the Geological Timescale

It is a record of the forms and geological events in earth's history

30

Rock Cycle Order

See powerpoint / geography book