11:00 〜 11:15
[MIS34-05] 後期白亜紀の深海底生有孔虫の炭素酸素同位体比変動から見た海洋循環と水温変動
Oceanic anoxic event 2 (OAE 2) occurred by global climatic warming in the latest Cenomanian to earliest Turonian. Global climate was gradually getting cool just after OAE 2. In the North Atlantic, deep water called NCW (Northern Component Water) was formed (Frank and Arthur, 1999; MacLeod et al., 2011; Martin et al., 2012), and oxygenated bottom water was flowing into North Atlantic by opening of Central Atlantic Gateway (CAG) between South Africa and South America in the early Turonian (Poulsen et al., 2001). Otherwise, climatic cooling from the early Campanian had affected SCW (Southern Component Water) forming in Southern high latitude and this deep water had flowed into Pacific (Brady et al., 1998; Huber et al., 1995; Murphy and Thomas, 2012; Robinson and Vance, 2012; Robinson et al., 2010).
It is cleared that deep water was sourced from high latitude during cooling time from the Campanian to Maastrichtian. However, deep ocean circulation before the Campanian has not yet clarified: especially, deep-water source during the warming periods. In this study, we reconstruct deep-ocean circulation during the late Cretaceous. We selected epifaunal species of benthic foraminifera from core samples in North Atlantic, South Atlantic, Southern Ocean, and Indian Ocean, to analyze carbon and oxygen isotopes in Kochi Core Center in Japan. We report new findings on deep-sea circulation and water temperature changes from the Cenomanian to Maastrichtian by compiling analyzing data and previous literature data.
References
Brady, E.C., DeConto, R.M., Thompson, S.L., 1998. Deep water formation and poleward ocean heat transport in the warm climate extreme of the Cretaceous (80 Ma). Geophys. Res. Lett. 25, 4205-4208.
Frank, T.D., Arthur, M.A., 1999. Tectonic forcings of Maastrichtian ocean-climate evolution. Paleoceanography 14, 103-117.
Huber, B.T., Hodell, D.A., Hamilton, C.P., 1995. Middle-Late Cretaceous climate of the southern high latitudes: stable isotopic evidence for minimal equator-to- pole thermal gradients. Geol. Soc. Am. Bull. 107, 1164-1191.
MacLeod, K.G., Londono, C.I., Martin, E.E., Berrocoso, A.J., Basak, C., 2011. Changes in North Atlantic circulation at the end of the Cretaceous greenhouse interval. Nat. Geosci. 4, 779-782.
Martin, E.E., MacLeod, K.G., Berrocoso, A.J., Bourbon, E., 2012. Water mass circula- tion on Demerara Rise during the Late Cretaceous based on Nd isotopes. Earth Planet. Sci. Lett. 327, 111-120.
Murphy, D.P., Thomas, D.J., 2012. Cretaceous deep-water formation in the Indian sector of the Southern Ocean. Paleoceanography 27, PA1211, http://dx.doi.org/ 10.1029/2011PA002198.
Poulsen, C. J., Barron, E. J., Arthur, M. A., Peterson W. H., 2001. Response of the mid-Cretaceous global oceanic circulation to tectonic and CO2 forcings, Paleoceanography, 16, 576-592, doi: 10.1029/2000PA000579.
Robinson, S.A., Murphy, D.P., Vance, D., Thomas, D.J., 2010. Formation of "Southern Component Water" in the Late Cretaceous: evidence from Nd-isotopes. Geology 38, 871-874.
Robinson, S.A., Vance, D., 2012. Widespread and synchronous change in deep-ocean circulation in the North and South Atlantic during the Late Cretaceous. Paleoceanography 27, PA1102, http://dx.doi.org/10.1029/2011PA002240.
It is cleared that deep water was sourced from high latitude during cooling time from the Campanian to Maastrichtian. However, deep ocean circulation before the Campanian has not yet clarified: especially, deep-water source during the warming periods. In this study, we reconstruct deep-ocean circulation during the late Cretaceous. We selected epifaunal species of benthic foraminifera from core samples in North Atlantic, South Atlantic, Southern Ocean, and Indian Ocean, to analyze carbon and oxygen isotopes in Kochi Core Center in Japan. We report new findings on deep-sea circulation and water temperature changes from the Cenomanian to Maastrichtian by compiling analyzing data and previous literature data.
References
Brady, E.C., DeConto, R.M., Thompson, S.L., 1998. Deep water formation and poleward ocean heat transport in the warm climate extreme of the Cretaceous (80 Ma). Geophys. Res. Lett. 25, 4205-4208.
Frank, T.D., Arthur, M.A., 1999. Tectonic forcings of Maastrichtian ocean-climate evolution. Paleoceanography 14, 103-117.
Huber, B.T., Hodell, D.A., Hamilton, C.P., 1995. Middle-Late Cretaceous climate of the southern high latitudes: stable isotopic evidence for minimal equator-to- pole thermal gradients. Geol. Soc. Am. Bull. 107, 1164-1191.
MacLeod, K.G., Londono, C.I., Martin, E.E., Berrocoso, A.J., Basak, C., 2011. Changes in North Atlantic circulation at the end of the Cretaceous greenhouse interval. Nat. Geosci. 4, 779-782.
Martin, E.E., MacLeod, K.G., Berrocoso, A.J., Bourbon, E., 2012. Water mass circula- tion on Demerara Rise during the Late Cretaceous based on Nd isotopes. Earth Planet. Sci. Lett. 327, 111-120.
Murphy, D.P., Thomas, D.J., 2012. Cretaceous deep-water formation in the Indian sector of the Southern Ocean. Paleoceanography 27, PA1211, http://dx.doi.org/ 10.1029/2011PA002198.
Poulsen, C. J., Barron, E. J., Arthur, M. A., Peterson W. H., 2001. Response of the mid-Cretaceous global oceanic circulation to tectonic and CO2 forcings, Paleoceanography, 16, 576-592, doi: 10.1029/2000PA000579.
Robinson, S.A., Murphy, D.P., Vance, D., Thomas, D.J., 2010. Formation of "Southern Component Water" in the Late Cretaceous: evidence from Nd-isotopes. Geology 38, 871-874.
Robinson, S.A., Vance, D., 2012. Widespread and synchronous change in deep-ocean circulation in the North and South Atlantic during the Late Cretaceous. Paleoceanography 27, PA1102, http://dx.doi.org/10.1029/2011PA002240.