12 710 Geological Oceanography ELEMENTS OF PALAEOCLIMATOLOGY PALAEOCEANOGRAPHY

12. 710: Geological Oceanography ELEMENTS OF PALAEOCLIMATOLOGY & PALAEOCEANOGRAPHY Olivier MARCHAL (omarchal@whoi. edu)

Assignments: 1. Reading assignment A paper will be assigned after each class. You should read this paper and be prepared for a short discussion (10 min) at the beginning of next class. 2. Problems sets Two problem sets will be given during this session of course 12. 710. They should be completed within 1 week. 3. Critical review You will be tasked with providing a written review (4 -5 pages) of one particular research article of your choice. In your review, you will summarize the article, put it in perspective, comment on its strengths and weaknesses, and suggest ways to improve the work. Emphasis should be placed on the (un)stated assumptions of the work and on the extent to which the conclusions are supported by the results of the paper. Put yourself in the position of very demanding reviewer! Your review is due at the end of this session (12/10).

The Geologic Time Scale (GSA, 2012)

General Plan 1) Introduction 2) Astronomical Theory of Climate Change 3) Pleistocene Ice Ages 4) Rapid Climatic Changes: Dansgaard-Oeschger & Heinrich Events 5) Last Glacial Maximum & Last (De)glaciation 6) Quantitative Analysis of Paleoclimate Records

1. Introduction 1) A definition of “climate” 2) The Climate System 3) The Radiative Budget of the Earth 4) The Estimated Climatic History of the Earth: A Brief Overview 5) The Paleoceanographic Archives: Sediments & Corals 6) Two Paleoceanographic Indicators: d 18 O & d 13 C of Foraminiferal Tests 7) The Cenozoic d 18 O & d 13 C Records

What is “climate”? • Climate 30 -yr average state of the atmosphere • Average State mean, variance, and higher moments of: - temperature - precipitation - wind velocity -. . . WMO (2015)

Idealized Temperature Profile in the Atmosphere Peixoto & Oort (1992)

The Climate System Saltzman (2002)

Black Body Radiation Curves & Absorption Spectra Peixoto & Oort (1992)

Global “Radiation” Budget Peixoto & Oort (1992)

Albedo, Shortwave, Longwave, & Net Radiative Fluxes Peixoto & Oort (1992)

Meridional Heat Transport by the Ocean & Atmosphere Peixoto & Oort (1992)

Schematic of Net Radiative Fluxes at T. O. A. HEAT FLUX Southern hemisphere HEAT FLUX Equator ATMOSPHERE OCEAN Northern hemisphere HEAT FLUX T. O. A.

Schematic of Tropospheric Mean Circulation Polar cell Ferrel cell Hadley cell Ferrel cell Polar cell F. Ronday (1990)

SCHEMATIC OF NORTH ATLANTIC SURFACE CIRCULATION Fratantoni (2001)

MERIDIONAL CIRCULATION IN THE ATLANTIC OCEAN Data: M. Mc. Cartney, L. Talley, J. Swift

MERIDIONAL CIRCULATION IN THE ATLANTIC OCEAN NADW Data: M. Mc. Cartney, L. Talley, J. Swift

MERIDIONAL CIRCULATION IN THE ATLANTIC OCEAN NADW AABW Data: M. Mc. Cartney, L. Talley, J. Swift

MERIDIONAL CIRCULATION IN THE ATLANTIC OCEAN AAIW NADW AABW Data: M. Mc. Cartney, L. Talley, J. Swift

MERIDIONAL CIRCULATION IN THE ATLANTIC OCEAN AAIW MOW NADW AABW Data: M. Mc. Cartney, L. Talley, J. Swift

Estimated Climatic History of the Earth Pleistocene Ice Ages, Rapid Climate Changes Cenozoic cooling Equable Climates of Mesozoic & Paleogene Late Paleozoic Ice Ages Precambrian glaciations (e. g. , “snowball” events) Faint Young Sun Paradox Frakes et al. (1992) Fig: Bradley (1999)

Palaeoceanographic Archives

Thickness of Marine Sediments Divins (2002)

Examples of Deep-Sea Sediment Cores Zachos et al. (2005)

Benthic Foraminifera in Deep-Sea Sediments white bar = 0. 1 mm Report STSM; C. S. Cervera (http: //cost-pergamon. eu/Administrative-doc/STSM-6276. pdf)

Distribution of Coral Reefs Source: NOAA, http: //oceanservice. noaa. gov/education/kits/corals/media/supp_coral 05 a. html

Emerged Coral Reef (Great Inagua Island, Bahamas) Courtesy: W. Thompson

Deep-Sea Scleratinian Corals Left to right: fossil Balanophyllia malouinensis, Flabellum curvatum, and 2 Individual Desmophyllum dianthus connected to one another (one coral grew on the other one). White scale bars correspond to 1 cm Fig: Burke et al. (2010) Photo: D. Blackwood (USGS)

Two Paleoceanographic Tracers: d 18 O & d 13 C of Foraminifera Tests

Oxygen Isotopic Composition, d 18 O • Definition

Controls on d 18 O of Inorganic Calcite Kim & O’Neil (1997)

Controls on d 18 O of Planktonic Foraminifera symbiotic planktonic foraminifer Non-symbiotic planktonic foraminifer Bemis et al. (1998)

Globigerina bulloides SEM image: Lucia de Abreu

d 18 O of Symbiotic Planktonic Foraminifera from Plankton Tows Bemis et al. (1998)

d 18 O of Planktonic & Benthic Foraminifera from Surface Sediments Neogloboquadrina pachyderma (left-coiling) Globigerina bulloides Uvigerina spp. Cibicidoides spp. Bemis et al. (1998)

d 18 Oc versus seawater d 18 O & temperature a 1 = 0. 97, a 2 = -0. 21 o/oo (o. C)-1 R = 0. 98 N = 91 data: Lynch-Stieglitz et al. (1999)

Relationship between Ocean d 18 O & Continental Ice Volume • Water made with 18 O has 1% lower vapor pressure than water made with 16 O. • During evaporation, 18 O is left behind in water relatively to 16 O. • The greater the removal of water from the ocean by evaporation, the greater the amount of ice on continents and the greater the 18 O enrichment in seawater relative to 16 O. • Seawater d 18 O is thus expected to be positively correlated with ice volume on land.

Last Glacial Maximum (19. 0 – 26. 5 ka): Ice Sheets Clark et al. (2009)

Last Glacial Maximum (19. 0 – 26. 5 ka): Sea Level Clark et al. (2009)

Last Glacial Maximum (19. 0 – 26. 5 ka): Pore Water d 18 O Adkins et al. (2002)

Distribution of d 18 O & Salinity in Surface Waters Broecker (1998)

Relationship between d 18 O & Salinity in Surface Waters Broecker (1998)

d 18 O: SUMMARY • d 18 O of calcite varies with d 18 O & temperature of ambient water: o/oo (o. C)-1 • Dd 18 O of BF & PF can be due to: - Dd 18 O of seawater due to DCIS - Dd 18 O of seawater due to other D’s - DT • In a glacial climate, seawater d 18 O & T conspire to produce high d 18 O of foraminiferal tests

Stable Carbon Isotopic Composition, d 13 C • Definition • d 13 C of DIC - increases during photosynthesis - decreases during respiration - is constant during Ca. CO 3 production & dissolution - is affected by air-sea CO 2 flux (for surface DIC)

d 13 C & PO 4 in western North Pacific GEOSECS station 346 (28 o. N, 121 o. W) Broecker & Peng (1982)

d 13 Cb versus d 13 C of Seawater DIC intercept = 0. 13 o/oo slope = 0. 90 R = 0. 94 N = 67 data: Duplessy et al. (1984)

Influence of Microhabitat on benthic foraminiferal d 13 C: Epifaunal vs. infaunal Mc. Corkle et al. (1990)

Influence of Microhabitat on benthic foraminiferal d 13 C: The “Mackensen effect” Mackensen et al. (1993)

COMPARISON BETWEEN d 13 C(benthic foraminifera) & d 13 C(bottom water) Courtesy of D. Mc. Corkle

COMPARISON BETWEEN d 13 C(benthic foraminifera) & d 13 C(bottom water) Courtesy of D. Mc. Corkle

The Cenozoic d 18 O & d 13 C Records Zachos et al. (2001)

END OF LECTURE 1 Reading assignment for next class: Zachos et al. , Trends, rhythms, and aberrations in global climate 65 Ma to present, Science, 292, 686 -693, 2001