Sedimentary rocks

Question 1

what are depositional environments

Answer 1

where sediments get left

Question 2

what are sediments

Answer 2

preweathered material

Question 3

what are the factors characterising depositional environments

Answer 3

types of transporting agent, type and composition of sediment, flow characteristics of transporting agent, site of deposition and types and abundance of organisms

Question 4

what is ithification

Answer 4

the process of transforming sediment into sedimentary rock. this is done but piles of sediment being compacting and minerals precipitating throughout the sediment

Question 5

what are the main types of sedimentary rocks

Answer 5

clastic, volcaniclastic, biogenic, organic and chemical

Question 6

what are clastic rocks made out of

Answer 6

made of clasts which are pieces of minerals or pre-existing rock formed through weathering

Question 7

what are volcaniclastic rocks made out of

Answer 7

clastic with a large part of those clasts have volcanic origin

Question 8

what are biogenic rocks made out of

Answer 8

made of particles originally produced by living organisms

Question 9

what are organic rocks made out of

Answer 9

made of compressed and heated plant material

Question 10

what are chemical rocks made out of

Answer 10

made from precipitated dissolved particles

Question 11

what is the relationship between the energy of the transporting medium and clast size

Answer 11

the energy determines the size of clasts the medium can transport, further away energy dissipates and clast size reduces

Question 12

what are the characteristics of conglomerates

Answer 12

contains clasts greater than 2mm that are rounded

Question 13

what are the characteristics of breccia

Answer 13

contains clasts greater than 2mm that are angular

Question 14

what are the characteristics of sandstone

Answer 14

contain clasts ranging from 2-0.25mm, feels gritty and can see with naked eye

Question 15

what are the characteristics of siltsone

Answer 15

contains clasts ranging from 0.063-0.004mm feels smooth

Question 16

what are the characteristics of claystone

Answer 16

contains clasts smaller than 0.004mm, feels smooth

Question 17

what are the characteristics of Mudstone/shale

Answer 17

contains clasts 0.063-0.25mm, feels smooth breaks into blocks where the shale is fissle/ splits easily into thin parallel layers

Question 18

what are the characteristics of limestone

Answer 18

biogenic sedimentary rock, composed primarily of calcium carbonate

Question 19

what are the characteristics of chalk

Answer 19

biogenic sedimentary rock, very fine grained limestone

Question 20

what are the characteristics of coal

Answer 20

biogenic sedimentary rock, forms from plant debris which accumulates in swampy environments

Question 21

what are the characteristics of evaporites

Answer 21

chemical sedimentary rock, forms from evaporation of mineral rich water

Question 22

what is bedding in sedimentary rocks

Answer 22

layers of rocks with differences with the layers above and below formed during the lithification process, defined by changes in grain size, composition and/or colour. upper and lower layers are known as bedding planes

Question 23

what do sedimentary rocks mean in relation to engineering

Answer 23

hard to generalize due to with range of lithologies and structures so thorough site investigation is needed