Geology week 2

Question 1

Metamorphic rocks

Answer 1

sedimentary or igneous rocks which have been subjected to heat or pressure

Question 2

What are the four processes involved in the production of sedimentary rocks?

Answer 2

1. Weathering - breaking up of pre existing rock
2. erosion - transportation of the particles
3. Deposition and accumulation of the particles
4. Lithification - cementation of a sediment so it becomes a rock

Question 3

Types of sedimentary rocks

Answer 3

1. clastic - form by compaction of rock fragments e.g. sandstone
2. Chemical - form by precipitation of minerals e.g. limestone
3. organic - form by accumulation of animal or plant matter e.g. coal

Question 4

Conglomerate rock

Answer 4

Contains a range of materials with larger boulders. A river brings materials from different places

Question 5

Breccia

Answer 5

more angular material and less transport distance. Could be landslide

Question 6

turbadites

Answer 6

Range of grain sizes formed by turbidity currents which are underwater landslides. Larger materials settle out first and smaller particles settle out further along

Question 7

Layering

Answer 7

Umbrella term for any type of layering

Question 8

Bedding

Answer 8

Large distinct layers that form over time (>1cm)

Question 9

Lamination

Answer 9

Very thin layers within a bed (mm) formed by minor variations in deposition

Question 10

Asymmetric ripples

Answer 10

Indicate flow direction, with the steep slops on the down current side

Question 11

Symmetric ripples

Answer 11

Form as a result of constant wave energy going back and forth

Question 12

What does cross bedding indicate

Answer 12

The direction of wind or water which deposited the material

Question 13

What is contact metamorphism

Answer 13

An igneous or sedimentary rock encounters a heat source

Question 14

What is orogeny

Answer 14

A mountain building event - a collision of lithospheric plates.

Question 15

Layering by physical properties

Answer 15

Lithosphere - solid and brittle 100km thick
Asthenosphere - solid, but ductile
Hydrosphere - Liquid
Atmosphere - gas
Outer core - liquid
Inner core - solid

Question 16

chemical properties of Crusts

Answer 16

Continental: 10-70 km thick and is granitic made mostly of oxygen, silicon)
Oceanic: 2-10 km thick. Basaltic (more magnesium, les silicon than other crust)

Question 17

chemical Properties of the mantle

Answer 17

3488km thick
made up of peridotite
solid but can deform so that it convects (moves in response to temperature differences)

Question 18

chemical properties of the core

Answer 18

2883 km radius, made up of
iron (Fe) and small amount of
nickel (Ni)

Question 19

What are the two main types of seismic waves

Answer 19

Body waves (p and s)
Surface waves (Love and raleigh)