paper 2

Question 1

Diagenesis definition

Answer 1

the chemical and physical processes that turn sediments into sedimentary rocks

Question 2

Diagenesis processes

Answer 2

1) cementation - infill of pore spaces by mineral cement
2) compaction - sediments squeezed by overlying sediment which decreases porosity and permeability
3) recrystallisation - crystals change in size and shape
4) dissolution - minerals dissolve where grains press into each other.

Question 3

siliclastic rocks

Answer 3

silica based rocks such as mudstone and sandstone

Question 4

methods to improve a dame site

Answer 4

Grouting - drilling hole and pumping in liquid cement to reduce porosity and improve stability of faults.
construct barrier underneath dam - prevent leakage underneath keeping it more stable

Question 5

how does temperature affect silica content of magma and why

Answer 5

silica content increases as temperature decreases due to fractional crystallisation which crystalises some contents of the magma which causes the silica to be more strong in the remaining mixture.

Question 6

How does silica affect magma

Answer 6

increased viscosity, - therefore divergent plate boundaries are mafic which produce shield volcanoes and convergent plate boundaries are silicic which create strata volcanoes.

Question 7

what is the focus

Answer 7

point inside the earth where the earthquake occurs

Question 8

what are ripple marks

Answer 8

sedimentary structures which indicate agitation by water

Question 9

what are carbon films

Answer 9

thin coatings of carbon

Question 10

mechanism of preservation resulting in carbon films

Answer 10

1) soft organism contains organic carbon
2) burial
3) subject to load pressure
4) causes increased temp and pressure
5) increased carbon % leaving carbon coating

Question 11

epifaunal/infaunal definitions

Answer 11

epifaunal - lived attached to the surface
infaunal - live in the sediment eg in burrows

Question 12

process of trilobites growing

Answer 12

1) cephalon breaks along facial structure
2) soft body exits the exoskelaton
3) it is vulnerable until new exoskelaton hardens

Question 13

sedimentary basin

Answer 13

low lying area in the earths crust where sediments accumulate

Question 14

how can the geometry of a sedimentary basin be determined

Answer 14

1) seismic surveys
2) correlation of sediments

Question 15

isochemical

Answer 15

having a constant chemical composition

Question 16

names of igneous intrusions by depth

Answer 16

hypabyssal - shallow intrusion
plutonic - deep intrusion

Question 17

bowens reaction series elements

Answer 17

1) olivine
2) pyroxene
3) hornblend
4) biotite

Question 18

fractional crystalisation

Answer 18

when certain elements crystalise faster resulting in a different sollution

Question 19

gravity settling

Answer 19

metallic minerals have higher densities which causes them to sink to the bottom of the magma chamber

Question 20

filter pressing

Answer 20

when a liquid-crystal magma mixture is subject to pressure, the liquid will be forced out

Question 21

BIF formation

Answer 21

1) iron in seawater originates from MOR volcanism
2) oxygen produced in the iron from photosynthesis
3) oxidation causes iron minerals to come out of solution

Question 22

Wilson cycle definition

Answer 22

process that explains the opening and closing of ocean basins due to the formation of supercontinents

Question 23

Wilson cycle process

Answer 23

1) rifting and break up of continents
2) opening of oceans by seafloor spreading
3 closure of oceans by subduction
4) mountain building by convergent continent-continent collision

Question 24

facies association

Answer 24

a group of sediments which represent one depositional environment

Question 25

erosion

Answer 25

the wearing of sediment during transport

Question 26

mature sediment

Answer 26

grains in the sediment are well sorted and well rounded

Question 27

types of cement

Answer 27

calcite, quartz, hematite, limestone

Question 28

dessecation cracks

Answer 28

cracks throughout soil due to lack of moisture

Question 29

cross bedding

Answer 29

forms during deposition on inclined surfaces and indicates the depositional environment had a constant flow

Question 30

p wave shadow zone

Answer 30

103-142 degrees - caused by liquid outer core refracting the waves

Question 31

relative dating methods

Answer 31

1) superposition - sediments deposited ontop of eachother with the lowest one being the oldest
2) cross cutting relationships - unconformity must be younger than the rock it cuts through
3) original hoizontallity - beds were deposited horizontally
4) included fragments - rocks containing fragments of older rocks

Question 32

methods of geotechnical site investigation

Answer 32

1) surface mapping (of folds and faults)
2) subsurface mapping (use of boreholes)
3) satellite photos

Question 33

convergent evolution

Answer 33

independent evolution of similar features with different unrelated species

Question 34

saurischian dinosaurs

Answer 34

Saurischian: reptile dinosaurs (forwards facing pubis) could be either:
* Therapod – Bipedal with sharp curved teeth, flesh eater.
* Sauropod – large size, long neck/tail, for legged stance, and herbivores.

Question 35

ornithischian dinosaurs

Answer 35

Ornithischian: Bird dinosaurs (backward facing pubis)
* Bipedal
* Plant eaters
* Thumb spike for defence
* Legs much larger than arms