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And the Mesozoic Ocean Th or collective redistirbution of any portion article of any by of this or collective redistirbution SPECIAL ISSUE FEATURE articleis has been published in Oceanography , Volume 19, Number journal of Th 4, a quarterly , Volume Greenhouse permitted photocopy machine, only is reposting, means or other AND THE World MESOZOIC OCEAN e Oceanography Society. 2006 by Th Copyright BY REISHI TAKASHIMA, HIROSHI NISHI, BRIAN T. HUBER, AND R. MARK LECKIE Earth’s climate has alternated between hurricanes, and enhanced amounts of icant achievements of DSDP and ODP with the approval of Th greenhouse (warm) and icehouse (cool) precipitation. Understanding the ocean- research and discusses future prospects modes throughout the Phanerozoic (Fig- climate system during past greenhouse for Integrated Ocean Drilling Program ure 1A). At present, Earth is in the midst climate modes is essential for more accu- (IODP) investigations in the fi eld of Me- gran is e Oceanography All rights Society. reserved. Permission of an icehouse climate. Nevertheless, the rately predicting future climate and envi- sozoic paleoceanography. or Th e Oceanography [email protected] Send Society. to: all correspondence rise of industrialization in the last two ronmental changes in a warming Earth. centuries has led to a dramatic increase The Mesozoic-early Cenozoic is NEW INSIGHTS in atmospheric CO2 from the burning known as a typical greenhouse pe- Determination of Mesozoic Ocean of fossil fuels, which, in turn, has led to riod caused largely by increased CO2 Temperature History signifi cant global warming (e.g., Rud- from elevated global igneous activity An important DSDP and ODP achieve- diman, 2000). Global warming could (Figure 1A–C). The mid-Cretaceous is ment was the reconstruction of the his- profoundly impact human life as a result marked by a major warming peak (Fig- tory of Mesozoic ocean temperature of consequent global sea-level rise, more ure 1D); it is characterized by globally changes based on geochemical methods numerous and increasingly powerful averaged surface temperatures more such as oxygen isotopes, TEX86, and al- ted to copy this article Repu for use copy this and research. to ted in teaching than 14°C higher than those of today kenone analyses. Oxygen-isotope data Reishi Takashima ([email protected]. (Tarduno et al., 1998), a lack of perma- have provided the greatest source of hokudai.ac.jp) is Research Fellow, Depart- nent ice sheets (Frakes et al., 1992), and paleotemperature reconstructions from e Oceanography Society, PO Box 1931, Rockville, MD 20849-1931, USA. ment of Earth and Planetary Sciences, Hok- ~ 100–200-m-higher sea level than that ancient oceans. However, the increasing kaido University, Sapporo, Japan. Hiroshi of today (Haq et al., 1987; Miller et al., prevalence of diagenetic alteration in Nishi is Associate Professor, Department 2005a) (Figure 1E). Studies using Deep older or more deeply buried rocks limits of Earth and Planetary Sciences, Hokkaido Sea Drilling Project (DSDP) and Ocean or prevents reliable isotopic data from University, Sapporo, Japan. Brian T. Huber Drilling Program (ODP) cores have being gleaned from biogenic calcite pre- is Curator, Smithsonian Institution, National advanced understanding of Mesozoic served in terrestrial outcrops. Compared Museum of Natural History, Washington, oceanography and climate, demonstrat- to many land-based sections, calcareous blication, systemmatic reproduction, reproduction, systemmatic blication, D.C., USA. R. Mark Leckie is Professor, ing that Mesozoic ocean circulation and microfossils of Cretaceous age recovered Department of Geosciences, University of marine ecosystems differed greatly from from samples drilled at DSDP and ODP Massachusetts, Amherst, MA, USA. those of today. This paper reviews signif- sites are often better preserved, and usu- 82 Oceanography Vol. 19, No. 4, Dec. 2006 30 Figure 1. Compilation G Percent of world’s (%) （ ） showing the changes original petroleum 20 in climate, and geologi- reserves generated by cal and paleontologi- source rocks (Klemme cal events through the and Ulminshek,1991) 10 Gas Phanerozoic. Oil 0 60 P/T F Percentage extinction (%) （ ） K/P T/J Late of marine genera (Raup Hot shale Devonian and Sepkoski, 1986) and 40 major Oceanic Anoxic Toarcian Oxfordian OAE2 Events 20 OAE1a–1d Weissert 0 30˚ 200 Glaciation (m) Sea Level 40 （E） Sea level changes 50 and continental 100 glaciation (Ridgwell, 60 Sea Level 2005) 70 0 (°paleolatitude) 80 Glaciation Continental -100 90 （D） Temperature (Frakes et al., 1992) Warm Cold 20 6000 （C） Carbon dioxide 2 CO2 Ratio of the mass ) 2 of atmospheric CO 4000 2 10 at a past time to (RCO that at present RCO2 Smoothed CO 2000 representation (Royer, in press) (Royer, (Berner, in press) record of the proxy 0 0 (ppm) 5 （B） Production rate of oceanic crust /year) 4 (Stanley, 1999) 3 (km 3 （A） Climate mode I GreenhouseIcehouse GreenhouseI Greenhouse Ice. (Frakes et al., 1992) Precambrian Paleog Creta Ordovician Neogene Jur Permian Carboni- Cambria Triassic Devonian Silurian ass ferous c eou ene ic s n Cenozoic Mesozoic Paleozoic 0 (Ma)100 200 300 400 500 600 Oceanography Vol. 19, No. 4, Dec. 2006 83 ally have not been as seriously affected 2003; Jenkyns et al., 2004). where the difference of temperature be- by complex tectonic and/or weather- According to isotopic records of sur- tween the mid-Cretaceous and the pres- ing processes. Exquisitely preserved face-dwelling planktic foraminifera, sea ent oceans is nearly 30°C (Figure 2). Bice foraminifera from the low-latitude surface temperatures reached a maxi- and Norris (2002) estimate that at least Demerara Rise (ODP Sites 1258–1261; mum of 42°C at the Demerara Rise (Bice 4500 ppm CO2 would be required to 4–15°N), mid-latitude Blake Nose (ODP et al., 2006), 33°C at the Blake Nose (Hu- match the above-mentioned maximum Sites 1049, 1050, 1052; 30°N), and ber et al., 2002), and 31°C at the Falkland temperatures, which is 11 times greater high-latitude Falkland Plateau (DSDP Plateau (Huber et al., 2002; Bice et al., than the modern atmospheric concen- Site 511; 60°S) in the Atlantic Ocean 2003) during the Turonian (~ 93–89 Ma tration. Using a more recent climate have been especially useful for recon- [million years ago]) (Figures 2 and 3). model, Bice et al. (2006) conclude that structing vertical and latitudinal tem- At comparable latitudes in the modern 3500 ppm or greater atmospheric CO2 perature gradients of the mid- through ocean, August surface water tempera- concentration is required to reproduce Late Cretaceous ocean (Figures 2 and 3). tures are 25–28°C at 0–20°N, 20–28°C at the estimated maximum sea surface tem- The TEX86 method is especially useful 20–40°N, and 0–5°C at 60°S (Thurman peratures of the Mesozoic tropical ocean. for organic carbon-rich sediments and and Trujillo, 1999). Consequently, these Because the Mesozoic paleo-tem- has provided excellent paleo-tempera- data suggest that Cretaceous warming perature estimates based on geochemical ture determinations (e.g., Schouten et al., was most prominent at high latitudes proxies are still insuffi cient in sediments older than Albian (> 112 Ma) and in ar- eas outside of the Atlantic Ocean, further investigations are needed to reconstruct a reliable spatial and temporal tempera- Mid-Cretaceous ture history during the greenhouse cli- 35 sea-suface mate of the Mesozoic. temperature ? gradient 30 Oceanic Anoxic Events Defi ning the concept of Oceanic Anoxic 25 Events (OAEs) was one of the most im- portant achievements of the early DSDP. 20 Cretaceous marine sediments in Europe Equator Temperature (˚C) Temperature are mainly comprised of white lime- 15 Present stone and chalk; however, distinct black, sea-surface temperature laminated organic-rich layers, termed 10 gradient 1260 390/1049 1257 392 “black shales,” are occasionally interca- 144 1050 690 Fl-533 689258 511 528 356 463 17 1258 627 1052 lated within these sequences (Figure 4). 5 Because organic carbon is preferentially 80˚S 60˚S 40˚S 20˚S 020˚N 40˚N 60˚N 80˚N preserved under anoxic conditions, ear- Latitude lier workers suggested that these black ODP/DSDP sites other core sites shales had accumulated locally in a Paleo sea-surface temperature weakly ventilated, restricted basin under Maastrichtian Turonian Cenomanian late Albian regional anoxic conditions. In the mid- 1970s, however, the discovery of black Figure 2. Latitudinal variations of surface ocean paleotemperature derived from oxy- shales at many DSDP drill sites from gen isotopes of planktonic foraminifera and TEX86. Modifi ed from Huber et al. (2002), Bice et al. (2003), and Jenkyns et al. (2004). the Atlantic, Indian, and Pacifi c Oceans 84 Oceanography Vol. 19, No. 4, Dec. 2006 led to recognition of widespread anoxic Burial of organic carbon, which pref- trial rocks such as dark gray- to black- conditions in the global ocean spanning erentially sequesters isotopically light colored mudstones, carbon isotope limited stratigraphic horizons (Figure 5). carbon during OAEs, resulted in a posi- excursions are a useful marker for rec- Schlanger and Jenkyns (1976) termed tive δ13C (13C/12C) excursion of 2–3‰ ognizing OAEs (e.g., Gröke et al., 1999; these widespread depositional black in the geologic record (Figure 3). Even Takashima et al., 2004). Recent advances shale intervals “Oceanic Anoxic Events.” if black shales are not visible in terres- in biostratigraphy and correlation us- Bulk Carbon Isotope Ocean Crust Production Paleo-temperature (Huber et al., 2002) (green line) Sea Level (Stanley and Hardie 1998) and Carbonate Platform Oceanic Anoxic Age (m) Blake Plateau S. high latitude (km2/year) Drowning (red arrow) Events (Site 1049) (Site 511 and 690) 13 D Ccarbonate -100 0m 100 200 3.5 4 4.5 1014 18 22 26 30 (˚C) 618222610 14 (˚C) 0 1 2 3 4(‰) North 60 Paleocene Atlantic Regio- Global gene nal 9 Maastrichitian Deccan Trap 70 Campanian 8 80 Upper Santonian OAE3 Coniacian 90 7 Turonian Caribbean Plateau OAE2 Cenomanian MCE 100 OAE1d Albian Miller et al.
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