1. Marine Sediments and Corals
(Chapter 6)

2. Dating Methods
Biogenic: oceanic information (temp., salinity, oxygen, etc.)

3. Dating Methods
Terrigenous: fluvial errosion, ice rafting (i.e., humidity-aridity, winds, etc.)

4. Special issue: Tropical SST at LGM
Dating Methods
Special issue: Tropical SST at LGM

5. Calcareous tests
Planktic (0-200 m) or Benthic (bottom)
“Composed of, containing, or characteristic of calcium carbonate, calcium, or limestone”
Foraminifera (zooplankton)
- almost macroscopic (

6. Calcareous tests
Planktic (0-200 m) or Benthic (bottom)
“Composed of, containing, or characteristic of calcium carbonate, calcium, or limestone”
Foraminifera (zooplankton)
- almost macroscopic
Coccoliths (

7. Calcareous tests
Planktic (0-200 m) or Benthic (bottom)
“Composed of, containing, or characteristic of calcium carbonate, calcium, or limestone”
Foraminifera (zooplankton)
- almost macroscopic
Coccoliths
Dinoflagellates
- cellulose tests with calcareous cysts
- important for SST and sea ice (

8. Siliceous tests
Planktic (0-200 m) or Benthic (bottom)
“Containing, resembling, relating to, or consisting of silica.”
Radiolaria (zooplankton) (

9. Siliceous tests
Planktic (0-200 m) or Benthic (bottom)
“Containing, resembling, relating to, or consisting of silica.”
Radiolaria (zooplankton)
Silicoflagellates (

10. Siliceous tests
Planktic (0-200 m) or Benthic (bottom)
“Containing, resembling, relating to, or consisting of silica.”
Radiolaria (zooplankton)
Silicoflagellates
Diatoms (algae) (

11. Where to look? Somewhat organism dependent Issues:
Differential removal
Scouring of bottom
Contamination by exotics

12. How used? Foram oxygen isotopes in calcium carbonate
Species assemblages
Morphological variations due to environment

13. Issues:
Continuous or seasonal presence?
Depth vs. life stage?

14. O Isotopes - Calcareous Tests
Urey (1947, 1948):
- Calcium carbonate crystallization
 18O > water concentration
- 18O enhancement varies with temperature:
T = (dc - dw) (dc - dw)2
dc = d18O of sample dw = d18O of sample’s water
Problem: What is dw ?
Changes with global ice volume
Can we estimate that?

15. Paleo dw : Deep ocean (benthic) temps. close to 0˚C
Deep ocean (benthic) temps. close to 0˚C
Little change from glacial periods
Benthic d18O due to paleoglaciation enhancement dw

16. O Isotopes - Calcareous Tests
18O enhancement & temperature - further complications
(1) Metabolic CO2 may alter dc (generally lower)
Species-dependent  use species in isotopic eq. with surrounding water

17. O Isotopes - Calcareous Tests
18O enhancement & temperature - further complications
(2) Forams tend to live at fixed water density: what happens with temp. and salinity change?

18. O Isotopes - Calcareous Tests
18O enhancement & temperature - further complications
(3) Calcification as foram descends: what is T(depth)?

19. O Isotopes - Calcareous Tests
18O enhancement & temperature - further complications
(4) Salinity effects: Estimate near-surface salinity?

20. O Isotopes - Calcareous Tests
18O enhancement & temperature - further complications
(4) Salinity effects: Estimate near-surface salinity?

21. Oxygen Isotope Stratigraphy
Primary d18O factor: ice volume on continents
Thus, a global signal  can synchronize cores
Still need absolute dating

22. Oxygen Isotope Stratigraphy
Primary d18O factor: ice volume on continents
Thus, a global signal  can synchronize cores
Still need absolute dating

23. Oxygen Isotope Stratigraphy
(Kleiven and Jansen, 2003)

24. Oxygen Isotope Stratigraphy
(Kleiven and Jansen, 2003)

25. Oxygen Isotope Stratigraphy
(Kleiven and Jansen, 2003)
Primary d18O factor: ice volume on continents

26. Oxygen Isotope Stratigraphy
South Atlantic
North Atlantic
(Kleiven and Jansen, 2003)
Primary d18O factor: ice volume on continents

27. Oxygen Isotope Stratigraphy
Primary d18O factor: ice volume on continents
Thus, a global signal  can synchronize cores
Also - local changes on land may not align with global changes!

28. Orbital Tuning d18O driven by orbital variations,
as mediated by terrestrial ice sheets

29. Orbital Tuning
Thus tune d18O time series by orbital signal

30. Orbital Tuning
Thus tune d18O time series by orbital signal

31. Relative Abundances Estimate T by mix of organisms? Schott (1935)
Cores not available until 1960s.
Figure shows quasi-periodic behavior

32. Relative Abundances
Figure shows quasi-periodic behavior

33. Calibration Figure shows quasi-periodic behavior(

34. Calibration Figure shows quasi-periodic behavior(

35. Calibration Figure shows quasi-periodic behavior(

36. N. pachyderma (left coiling)
G. bulloides
Figure shows quasi-periodic behavior
G. ruber (

37. Calibration G. bulloides G. ruber Figure shows quasi-periodic behavior(

38. Calibration N. pachyderma (left/right coiling)
Figure shows quasi-periodic behavior (

39. Calibration N. pachyderma (left coiling)
Figure shows quasi-periodic behavior (

40. Relative Abundances More sophisticated: use multiple species and
principle patterns of species variations (principal components)
Major assemblages:
Polar
Subpolar
Transitional
Subtropical
Gyre
Figure shows quasi-periodic behavior

41. Relative Abundances Calibration outcome (contemporary):
Figure shows quasi-periodic behavior
Calibration outcome (contemporary):
Tw = 23.6 A B C D K

42. Relative Abundances 18O from same core
Figure shows quasi-periodic behavior
18O from same core
Apply calibration formula to core abundances:
Tw = 23.6 A B C D K

43. Controversy: Tropical SST
Were tropical sea-surface temperatures
colder or like present
at last glacial maximum (max 18O in Stage 2)?

44. Controversy: Tropical SST
colder or like present ?
Tropical snow lines lower: lapse rate ?
GCMs need SST  5-6˚C for lowered snow line.
Corals in Pacfic (16˚S) and Barbados: SST  ~ 5˚C
Noble gases in Brazil groundwater: T~ 5˚C
Peruvian glacier: 18O  ~ 8 o/oo
Central Australia (Emu eggshells): T~ 9˚C
Assemblages: SST  ~ 1 - 2˚C
Alkenones: SST  ~ 1 - 2˚C
Careful reassessments: No significant cooling
Broecker (1986)
Thunell et al. (1994)
Stott & Tang (1996)

45. Controversy: Tropical SST
colder or like present ?
Missing cold-intolerant forams:
T > 7 - 8˚C ?
Contamination of “modern” core tops (used for calibration) by early Holocene faunas?
Short cold episodes?

46. DSST: Present - 18k BP Note locations of cores! August
Figure shows quasi-periodic behavior
Note locations of cores!
August

47. DSST: Present - 18k BP Note locations of cores! February
Figure shows quasi-periodic behavior
Note locations of cores!
February

48. Corals Hermatypic Corals: Build reefs
Symbiotic relationship with algae
Depth limited by sunlight ( m)
Limited also by temperature (~ 20˚C) and nutrient flow
Clipperton Atoll (10 N, 109 W) (

49. Corals Growth rate varies: Yellow bands = El Niño years(

50. Corals Growth rate can also indicate annual cycle:
Revealed under UV light
From Great Barrier Reef, Australia (

51. Corals
Potential utility

52. Corals Potential utility: SST from paleo-reefs?
Possibly indicate sea-level changes?

53. Fossil Pollen in Marine Sediments
A record of wind and desert changes
(H. Hooghiemstra, 2004)

54. Fossil Pollen in Marine Sediments
(H. Hooghiemstra, 2004)

55. Fossil Pollen in Marine Sediments
(H. Hooghiemstra, 2004)

56. Fossil Pollen in Marine Sediments
(H. Hooghiemstra, 2004)

57. Fossil Pollen in Marine Sediments
(H. Hooghiemstra, 2004)

58. Thermohaline Circulation

59. Thermohaline Circulation

60. Thermohaline Circulation

61. Heinrich Events

62. Heinrich Events

63. Heinrich Events

64. Heinrich Events

65. Heinrich Events

66. Heinrich Events Model tidal amplitudes @ 45k BP [m]
(Arbic et al., 2004)

67. Heinrich Events Tidal amplitude @ Hudson Strait
(sea level )+ marine-based ice
(sea level ) only
contemporary
(Arbic et al., 2004)

68. Heinrich Events
Did the European Ice Sheet Surges Trigger the North Atlantic Heinrich Events? (Grousset et al., 1999)
Use Sr-Nd isotopic compositions on the bulk lithic fraction of Heinrich layers (ice rafted debris):
Dominant Laurentide signal H1, H2, H4, H5
European signal H3
BUT…
Early H4 European dominant
Late H4 Laurentide dominant
 European trigger?

69. End of Last Glaciation

70. End of Last Glaciation

71. End of Last Glaciation

72. End of Last Glaciation

73. Changes in CO2: Ocean Role

74. Changes in CO2: Ocean Role

75. Marine Sediments and Corals
(Chapter 6)
END