envs3240

Question 1

define weather

Answer 1

constantly changing over a period of days/months such as cyclones, wet and dry seasons and storms.

Question 2

define climate variability

Answer 2

period of years which includes ENSO and other oscillations

Question 3

define climate change

Answer 3

observed change over a period of decades such as global warming, SLR and ocean acidification

Question 4

Diurnal cycles complete within:

Answer 4

24 hours such as tides?

Question 5

seasonal cycles have transitions every:

Answer 5

3 months

Question 6

what is a benchmark

Answer 6

an estimated set conditions that is thought to be the norm for that period - any conditions above or below the benchmark is thought to be out of the ‘norm’

Question 7

what human actions have altered evolutionary outcomes?

Answer 7

intense harvesting, antibiotics, pesticides, genetically engineered organismsw

Question 8

what was the first major impact of humans on the environment?

Answer 8

fire

Question 9

when did the holocene start

Answer 9

11700 kya

Question 10

what is ENSO

Answer 10

el nino southern oscillation with neutral, positive and negative phases. El nino is the negative phase with cooler sea temps caused by reversed trade winds. La nina is positive with warmer oceans and stronger trade winds

Question 11

what is SAM

Answer 11

southern annular mode: influences rainfall and temp in south eastern aus. neutral, negative and positive that last 1-2 weeks.

positive sam = lower and increased rain in summer and winter in east coast

negative sam = decreased chance of rain in eastern aus and increased in west aus

Question 12

what is the IOD

Answer 12

indian ocean dipole: changes in SST affects rainfall in Aus. negative brings less rain due to cooler water temps

Question 13

what is the IPO

Answer 13

inter-decadal pacific oscillation

Question 14

what are the 3 milankovitch cycles

Answer 14

eccentricity (orbit)
precession (wobble)
obliquity (tilt)

Question 15

what is eccentricty

Answer 15

the orbit of the earth around the sun. has a periodicity of 96ka and goes from elliptical to circular which affects the glacials

Question 16

what is obliquity

Answer 16

the tilt on earths axis. directly controls the seasons and tilts between 22.1 to 24.5˚. periodicity of 42ka.

Question 17

what is precession

Answer 17

the wobble of the earth. caused by the gravitational pull of the moon and the sun. affects the monsoon.

Question 18

what is a stadial

Answer 18

following an interglacial with a period of rapid cooling

Question 19

what is an interstadial

Answer 19

following a glacial with a period of rapid warming

Question 20

what happens to oxygen 16 during an interglacial

Answer 20

ocean gets enriched with oxygen 16 and glacials are depleted

Question 21

what happens to oxygen 16 during glacials

Answer 21

ocean gets depleted and ice gets enriched with 16 o

Question 22

during the last interglacial in Britain around 120kya what type of animals roamed around?

Answer 22

hippos, white lions and elephants.

Question 23

what gives the quaternary the distinctive character?

Answer 23

the combination of high amplitude and frequency of climatic oscillations

Question 24

what are the 3 main proxies

Answer 24

deep sea sediment cores, ice cores and speleothems

Question 25

what causes the ratio of oxygen isotopes to change

Answer 25

temp, evaporation, precipitation and currents etc.

Question 26

what does AMS stand for and what does it do

Answer 26

accelerator mass spectrometer. accelerates ions to high kinetic energies before mass analysis. its dissolved into a gas and ratios are measured (18o vs 16o)

Question 27

what is fractionation

Answer 27

the breakage of 16o from 18o during evaporation

Question 28

advantages of deep sea sediment cores?

Answer 28

MOI stages, good for global correlations. can reach millions of years of data.

Question 29

disadvantages of deep sea sediment cores?

Answer 29

low resolution, sediment mixing, bioturbation

Question 30

advantages of ice cores?

Answer 30

very high resolution, timing of major events, multiple proxies, time parallel horizons, independent chronology and marine-terrestial correlation

Question 31

how long is the quaternary period

Answer 31

2.6 Ma

Question 32

what are the names of the ice drilling stations?

Answer 32

EPICA Dome C, GISP, GRIP AND NGRIP

Question 33

what is the age of the oldest ice core

Answer 33

800ka

Question 34

what is the coldest and driest period?

Answer 34

interstadials

Question 35

how many glacial cycles in the quaternary?

Answer 35

over 100

Question 36

what are examples of proxies?

Answer 36

flowstone, varves, coleoptera bettles, loess, coral

Question 37

what are examples of lithological evidence

Answer 37

glacial, periglacial sediments, palaeosols, loess, lake levels and sediments, wind blown, cave, deep sea sediments and ice corres

Question 38

what are examples of biological evidence

Answer 38

pollen, diatom, plant macrofossil, fossil insect, molluscs, ostracod, formaninfera and vertebrates.

Question 39

disadvantages of ice cores

Answer 39

complex flow patterns, melting and refreezing, basal ice, very expensive and time consuming.

Question 40

advantages of speleothem dating?

Answer 40

terrestial multi proxy records, no bioturbation or diffusion, high resolution, accurately dated with U seriesd

Question 41

disadvantages of speleothem dating

Answer 41

isotopic equilbrium difficult to establish, kinetic fractionation (from evaporation), digenetic alteration, changes in isotopic ratios before entering caves

Question 42

in speleothems, when is there enriched oxygen 18 ratios

Answer 42

when there is low rainfall periods (glacials)

Question 43

in speleothems, where is there depleted oxygen 18 ratios

Answer 43

when there is high rainfall (interglacials)

Question 44

what is the most widely used biological evidence

Answer 44

pollen

Question 45

what is the connection between global warming and next ice age

Answer 45

melting ice increases freshwater discharge and disrupts the thermohaline circulation causing it to stop and cause an ice age

Question 46

is loess a glacial or interglacial feature

Answer 46

glacial.

Question 47

how can OSL signal be reset

Answer 47

light, heat and pressure

Question 48

what are the naturally occuring radioisotopes

Answer 48

Thorium, Uranium, Rubidium and Potassium

Question 49

what is more useful: inaccurate but precise or inprecise and accurate

Answer 49

inprecise and accurate

Question 50

whats the best dating technique for widest range of materials

Answer 50

radiocarbon

Question 51

how far can radiocarbon dating be used

Answer 51

60ka

Question 52

where are the oldest sediments and caves found in limestone towers

Answer 52

at the highest elevations

Question 52

what is a flowstone

Answer 52

a rock that forms from calcite flowing in layers over a flat surface

Question 53

can caves form in sandstone and lava

Answer 53

yes, including marble, karst and limestone.

Question 54

why are caves good preservers

Answer 54

capped by protected flowstone layer, protect from scavengers, protected from weathering and erosion, and rapidly build up with sediment that bury and protect fossils

Question 55

best places in aus for early modern humans

Answer 55

Kow swamp and Lake Mungo

Question 56

good overlap of humans and megafauna in aus

Answer 56

tight entrance cave

Question 57

where are key megafauna sites in aus

Answer 57

lake mungo, cuddie springs, nullabor plain and narracoorte caves

Question 58

what are sapropels

Answer 58

organic rich sediments found in the sea floor that reflect orbital precssion and indicate long term drying trend.

Question 59

what minerals are used in OSL

Answer 59

quartz and feldspar

Question 60

how are the electrons trapped in the minerals for OSL

Answer 60

in the cracks and imperfections

Question 61

what is the process of radiocarbon 14 formation

Answer 61

a nuclear reaction between neutrons produced by cosmic rays and N14 to create 14 CO2 which is taken up by organism.

Question 62

how is radiocarbon 14 measured

Answer 62

using a AMS which counts the 14c atoms

Question 63

what are the 4 ways sediment can be reset to zero

Answer 63

formation by crystallisation extreme pressure heating above 200-300˚C exposure to light

Question 64

what material is used for radiocarbon dating

Answer 64

organics, carbonates

Question 65

what happens to electrons during buried sediments

Answer 65

it accumulates and gives a larger value when exposed to light in OSL

Question 66

what were some of the bridges to dispersal

Answer 66

land bridges, sea level fall, ocean currents and rainforests

Question 67

what values of o18 does ice cores have

Answer 67

-30 to -40 % per mill

Question 68

what values y axis does dust indices have

Answer 68

DD (Ca) ppm

Question 69

what values of o18 does speleothems have

Answer 69

-6 to -10

Question 70

what values of o18 does deep sea cores have

Answer 70

-1 to -3 or -100 +

Question 71

what are sapropels

Answer 71

organic rich sediments caused by monsoon which floods the nile.

Question 72

what do sapropels correlate with (2?)

Answer 72

precession (21ka cycle affecting monsoon) and long term drying trend over 3 million years which peaked at 1.8-1.6 Ma

Question 73

what does 2.9-2.6 Ma describe in africa

Answer 73

Australopiths and homo habilis emergence, however none left africa. Homo habilis was a handy man using tools.

Question 74

what does 1.9-1.6 Ma describe in africa

Answer 74

homo erectus emergence and moves out of africa using mode two tools and use of fire.

Question 75

when could homos leave africa

Answer 75

2-1 Ma due to lack of desert

Question 76

when were homos trapped in africa

Answer 76

1-0.5 Ma due to strengthening monsoon, extensive desert and Himalaya uplift

Question 77

when did homo erectus reach SEA

Answer 77

1.8Ma

Question 78

what stopped homo erectus from getting to aus

Answer 78

The Wallace line which separated marsupials and mammals and the different types of environment. erectus preferred grassy areas.

Question 79

what was at mungo 3 site

Answer 79

articulated bones

Question 80

what was at mungo 1 site

Answer 80

oldest ceremonial burial

Question 81

when was mungo dated to

Answer 81

42ka using ESR of bone and TL and OSL of sand dunes.

Question 82

where are the megafauna sites in australia top 3

Answer 82

cuddie springs, narcoorte cave and tight entrance cave

Question 83

how many animals went extinct when humans arrived in aus

Answer 83

90%

Question 84

what is the one kill per person per decade called

Answer 84

Imperceptible overkill

Question 85

what is the rapid overkilling model called

Answer 85

blitzkreig?

Question 86

how long were megafauna and humans overlapping in cuddie springs

Answer 86

15,000 years

Question 87

what happened to fire regimes during MIS 4 to 2

Answer 87

a stable and decrease in burning until MIS 2 and then a sharp increase in the holocene

Question 88

what trees had low abundance before 38ka

Answer 88

casuarina and eucalyptus

Question 89

what is accuracy in dating

Answer 89

how confident the value is, or how aligned they are with one another

Question 90

what is precision in dating

Answer 90

the range of the date +/-, how small the values are together.

Question 91

what is the importance of articulated bones

Answer 91

rapid burial which is synchronous with the sediments around it

Question 92

what kind of environments are best for OSL

Answer 92

aeolian environments