Studies & Papers

Question 1

Schidlowski Study (1988)

Answer 1

presented isotopic evidence that life existed on earth 3.8 billion years ago.

Question 2

Nutman Discovery (2016)

Answer 2

Found 3,700 million year old microbial structures.

Question 3

Welch & Parsons Salmon Study

Answer 3

Analyzed various salmons muscle tissues for 13C and 15N.
Areas of deep ocean water upwelling have abundant nitrate. There is little recycling of N so low tropic organisms have low 15N

Question 4

Schwarcz cod study

Answer 4

Examined the 13C of cod in Nova Scotia. Overall 13C values became less negative as fish aged

Question 5

In schwarcz cod study 3 13C values were hypothesized what are they?

Answer 5

1) 13C of sea water - Bicarbonate 13C decreases as water depth increases

2) 13C of diet - as fish consume species from higher trophic levels 13C increases.

3) 13C of metabolism - Metabolism slows with age so 13S of aragonite increases with age

Question 6

Hoie fish study

Answer 6

Studies oxygen isotope fractionation between aragonite in fish ears and water was temperature sensitive.
The stable isotopes of cod can give precise and accurate estimates of water temperature in which the fish lived in.

Question 7

Hoie fish study limitations

Answer 7

Need to know the 18O of water

Question 8

Sponheimer and Lee-Thorp animal study

Answer 8

Isotopic information from the tooth enamel helps to determine aminals diet and can assist in determining habitat.

Question 9

Sponheimer and Lee-Thorp results fell into 4 groups

Answer 9

1) C4 consumers are grassland grazers with high 13C/12C ratios

2) C3 consumers are tree & shrub browsers with a low 13C/12C ratio

3) Mix feeders have intermediate 13C/12C ratios

4) Australopithecines & hyenas have intermediate 13C

Question 10

What was Sponheimer and Lee-Thorp other study?

Answer 10

in 2010 they added fossil homin 13C isotopic data. Aridipithecus ramidus had negative 13C values supporting the consumption of C3 as opposed to C4 food sources

Question 11

SIllen Study

Answer 11

Showed the crust of earth has variable 87Sr/86Sr ratios.
The older the continental crust the higher the 87Sr/86Sr ratios.

The ratios go up with decay of 87Rb. The 87Sr/86Sr of fossil bones can reflect diagenetic effects

Question 12

Woollers wooley mammoth study

Answer 12

The study is based on 87Sr/86Sr ratios. Plants consumes by the mammoth reflect isotopic composition of underlying rocks.

Isotopes can reconstruct an animals lifetimes movement across 1000s of km.

a high end of life 15N value indicated starvation

Question 13

GISP

Answer 13

Greenland ice (90,000 years old)

Question 14

GRIP

Answer 14

Greenland ice (100,000 years)

Question 15

Vostok

Answer 15

Antarctica (420,000 years)

Question 16

EPICA

Answer 16

European (740,000 years)

Question 17

Stuiver & Grootes ice study

Answer 17

Studied GISP 18O ratios which are indicative of surface temperature. Cold period are characterized by ice with more negative 18O values than ice with warm periods

Question 18

Petit ice core study

Answer 18

analyzes vostock ice cores

Question 19

Agustin Ice Study

Answer 19

analyzed antarctic core that extends back to 740,000 years. There is a change in the shape of cycles around 450,000 years ago

Question 20

Brook and Buizert

Answer 20

Analyzed Dome C (800,000) and Dome Fuji