Climate of the past Limitations

This work is part of the NWO VIDI project 016.161.365, which is

financed by the Netherlands Organisation for Scienti fic Research (NWO).

colder

warmer

0 10 20 30 40 50 60

Age (million years ago, Ma)

5 4 3 2 1 0

−1

0 4 8 Sea level (m) 12

-120 -90 -60 -30 0 30

Antarctic ice sheets

Northern Hemisphere ice sheets

Mid −Miocene Climatic Optimum

H o lo c e n e

Pleistocene

Pliocene Miocene Oligocene Eocene Paleocene

δ 18 O (‰ )

Temperature in NH ( ℃)

Ic e- fr ee temp er a tu re (℃ )

Paleocene −Eocene Thermal Maximum

0 7 14 21

Eearly Eocene Climatic Optimum

Mid −Eocene Climatic Optimum

Eocene −Oligocene Transition

Aim: reconstructing Cenozoic climate history

Temperature (°C)

25 40

60 5 0

0.450 0.500 0.550 0.600 0.650 0.700 0.750

8 9 10 11 12 13 14

47CDES90 (‰)

10 ⁶ /T ²

b

16 O ¹² C ¹⁶ O

16 O ¹³ C ¹⁸ O

16 O ¹³ C ¹⁶ O

16 O ¹² C ¹⁸ O

Figure 1: Cenozoic oxygen isotope ( δ ¹⁸ O) compilation from deep-sea benthic

foraminifera (gray) ^{1, 2} . Split into sea-level (ice-volume) (blue) and temperature (green) components—relative to present-day—from a transient 3D ice-sheet model ³ .

Figure 2: Heavier stable isotopes of oxygen ( ¹⁸ O and ¹⁷ O) and

carbon ( ¹³ C) are preferentially embedded in CO ₃ ^2– when surrounding temperatures are cooler. Right figure adapted from ⁵ .

e ideal carbonate standard distribution signi�cantly

reduces the uncertainty of the �nal temperature estimate.

For a sample of 0 °C, changing the distribution of standards results in a 24%

decrease in the uncertainty. Adding a new cold standard would result in a 35% decrease.

Climate of the past

e uncertainty in measurements requires many replicate measurements, and thus ample sample material.

We try to improve measurement precision and accuracy by

including many standards in an optimal measurement regime.

Limitations

Shipping

Coring

Sieving and Picking

Cleaning and Weighing

Measuring

Processing

Preliminary conclusions

Methods

I do not show th

is here, ask me a

bout it and I'll show you extr

a figur

es! Clumpy team UU

Clumped isotopes are only a ffected by temperature ^{18 O (‰)}

1.5 2.0 2.5

Eccentricity (-) 0.00

0.02 0.04 0.06

49 57 68

19.5 20 22.5 23 27 27.5

Age (Ma)

Strong 100-kyr cycles in δ ¹⁸ O:

sea-level or temperature?

Stable ice-sheets?

Clumped Isotopes

Walvis Ridge

ODP Site 1264