Late Paleocene Osmium Isotope Data Ravizza, G.; Norris, R.N.; Blusztajn, J.; Aubry, M-P. Ravizza, G. Norris, R.N. Blusztajn, J. Aubry, M-P. earth science/paleoclimate/paleoceanography (187Os/188Os,sediment,null,dimensionless,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (187Re/188Os,sediment,null,dimensionless,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (delta 13C,carbonate,null,per mil PDB,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (rhenium,sediment,null,parts per trillion,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (delta 18O,carbonate,null,per mil PDB,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (osmium,sediment,null,parts per trillion,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (DSDP 213>LATITUDE -10.22>LONGITUDE 93.9) (DSDP 549>LATITUDE 49.088>LONGITUDE -13.098) In the latest Paleocene an abrupt shift to more negative delta13C values has been documented at numerous marine and terrestrial sites [Bralower et al., 1997; Cramer et al., 1999; Kaiho et al., 1996; Kennett and Stott, 1991; Koch et al., 1992; Stott et al., 1996; Thomas and Shackleton, 1996; Zachos et al., 1993]. This carbon isotope event (CIE) is coincident with oxygen isotope data that indicate warming of surface waters at high latitudes of nearly 4°--6 °C [Kennett and Stott, 1991] and more moderate warming in the subtropics [Thomas et al., 1999]. Here we report 187Os/188Os isotope records from the North Atlantic and Indian Oceans which demonstrate a >10% increase in the 187Os/188Os ratio of seawater coincident with the late Paleocene CIE. This excursion to higher 187Os/188Os ratios is consistent with a global increase in weathering rates. The inference of increased chemical weathering during this interval of unusual warmth is significant because it provides empirical evidence supporting the operation of a feedback between chemical weathering rates and warm global climate, which acts to stabilize Earth's climate [Walker et al., 1981]. Estimates of the duration of late Paleocene CIE [Bains et al., 1999; Bralower et al., 1997; Norris and Röhl, 1999; Röhl et al., 2000] in conjunction with the Os isotope data imply that intensified chemical weathering in response to warm, humid climates can occur on timescales of 104--105 years. This interpretation requires that the late Palcocene thermal maximum Os isotope excursion be produced mainly by increased Os flux to the ocean rather than a transient excursion to higher 187Os/188Os ratios in river runoff. Although we argue that the former is more likelythan the latter, we cannot rule out significant changes in the 187Os/188Os ratio of rivers. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Ravizza, G. Investigator : Norris, R.N. Investigator : Blusztajn, J. Investigator : Aubry, M-P. 2001-01-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/2587 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/dsdp213-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/ravizza2001 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/dsdp549-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/dsdp213-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/ravizza2001 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/dsdp549-tab.txt English https://www.ncdc.noaa.gov/paleo/study/2587 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/dsdp213-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/ravizza2001 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/dsdp549-tab.txt Ravizza, G., R.N. Norris, J. Blusztajn, and M-P. Aubry. 2001. An osmium isotope excursion associated with the late Paleocene thermal maximum: Evidence of intensified chemical weathering. Paleoceanography 16(2):155-163. -13.098 -10.22 93.9 49.088