Vostok Ice Core Data for 420,000 Years: Readme file --------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program --------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Vostok Ice Core Data for 420,000 Years LAST UPDATE: 11/2001 (Original Receipt by WDC Paleo). CONTRIBUTOR: Jean Robert Petit, LGGE-CNRS. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2001-076 SUGGESTED DATA CITATION: Petit, J.R., et al., 2001, Vostok Ice Core Data for 420,000 Years, IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2001-076. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J., Delaygue G., Delmotte M., Kotlyakov V.M., Legrand M., Lipenkov V., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M., 1999, Climate and Atmospheric History of the Past 420,000 years from the Vostok Ice Core, Antarctica, Nature, 399, pp.429-436. ADDITIONAL REFERENCES: Barnola, J.M., Raynaud, D., Korotkevich, Y.S. & Lorius, C., 1987. Vostok ice core provides 160,000-year record of atmospheric CO2. Nature, 329, 408-414. Barnola, J.M., Pimienta, P., Raynaud, D. & Korotkevich, Y.S., 1991. CO2 climate relationship as deduced from the Vostok ice core: a re-examination based on new measurements and on a re-evaluation of the air dating. Tellus, 43B, 83-91. Chappellaz, J., Barnola, J.-M., Raynaud, D., Korotkevich, Y.S. & Lorius, C. 1990. Ice-core record of atmospheric methane over the past 160,000 years. Nature, 345, 127-131. Jouzel J., C. Lorius, J. R. Petit, C. Genthon, N. I. Barkov, V. M. Kotlyakov, and V. M. Petrov, 1987, Vostok ice core: a continuous isotope temperature record over the last climatic cycle (160,000 years), Nature, 329, 1987, 402-408. Jouzel J., N. I. Barkov, J. M. Barnola, M. Bender, J. Chappelaz, C. Genthon, V. M. Kotlyakov, V. Lipenkov, C. Lorius, J. R. Petit, D. Raynaud, G. Raisbeck, C. Ritz, T. Sowers, M. Stievenard, F. Yiou and P. Yiou, 1993, Extending the Vostok ice-core record of paleoclimate to the penultimate glacial period, Nature, 364, 1993, 407-412. Jouzel J., C. Waelbroeck, B. Malaizé, M. Bender, J. R. Petit, N. I. Barkov, J. M. Barnola, T. King, V. M. Kotlyakov, V. Lipenkov, C. Lorius, D. Raynaud, C. Ritz and T. Sowers, 1996,Climatic interpretation of the recently extended Vostok ice records, Clim.Dyn., 12, 513-521. Legrand M., C. Lorius, N;I. Barkov, V.N. Petrov, 1988, Vostok (Antarctica) ice core: atmospheric chemistry changes over the last climatic cycle (160,000 years), Atmos. Environ. 1988, 22, 317-331. Lorius C., J. Jouzel, C. Ritz, L. Merlivat, N. I. Barkov, Y. S. Korotkevitch, and V. M. Kotlyakov, 1985, A 150,000-year climatic record from Antarctic ice, Nature, 316, 591-596. Petit J.R., L. Mounier, J. Jouzel, Y. Korotkevitch, V. Kotlyakov and C. Lorius, 1990, Paleoclimatological implications of the Vostok core dust record, Nature, 343, 56-58. Sowers T. M. Bender, L. D. Labeyrie, J. Jouzel, D. Raynaud, D. Martinson, and Y. S. Korotkevich, 1993, 135,000 year Vostok - SPECMAP common temporal framework, Paleoceanography v.8, p. 737-766. GEOGRAPHIC REGION: Antarctica PERIOD OF RECORD: 0-422 KYrBP LIST OF FILES: Readme_petit1999.txt (this file), GT4nat.txt, deutnat.txt, dustnat.txt, nanat.txt, ch4nat.txt, co2nat.txt, o18nat.txt (Tab-delimited ASCII format). DESCRIPTION: Vostok Ice Core Data for 420,000 Years Files content: "GT4" ice core chronology (gas and ice chronology), Deuterium and reconstructed temperature, Dust content, Sodium concentrations, CO2, CH4, atmospheric oxygen composition. Vostok time scales : file "GT4nat.txt" Column 1: depth (m) Column 2: Age of the ice (GT4 chronology) Column 3: Gas Age as deduced from the Barnola et al. (1991) model. Deuterium - data : file « deutnat.txt » Column 1 -Depth (m) Column 2 -Ice Age (GT4) Column 3 –Deuterium content in ‰ SMOW (Standard Mean Ocean Sea Water). Deuterium measurements have been performed on three adjacent cores 3G, 4G and 5G (see Figure 1 of Jouzel et al., 1996). It combines results successively published in Jouzel et al. (1987, 1993 and 1996). Column 4 -Temperature difference wrt the mean recent time value (i.e. corresponding departure from –438 ‰ mean deuterium value) Deuterium data is from core 3G between 138 and 2083 meters below surface (mbs) (with one long missing section between 312 and 320 mbs), from core 4G between 8 and 138 mbs and between 1920 and 2546 mbs and from core 5G between 2504 and 2757 mbs. Ash layers help to make link between cores. No correction was applied for 3G and 4G core taken as reference depth. For 5G samples, a value of 3.41 m have been added to the depth measured in the field below depth of 2500 m. Deuterium values (column 3) have been measured on ice samples of length comprised between 0.5 and 2 m (down to 2080 m) then every 1 m. Data was re-interpolated on 1m intervals afterwards. The ice recovery is 85% or higher. Measurement accuracy is of ± 0.5‰ SMOW (1 s). From the surface down to 7 m a constant value (derived from surface and pits samples) of -438.0 ‰ is reported. The temperature change indicated in column 4 (temperature above the inversion). This temperature is calculated using a deuterium/temperature gradient of 9‰/°C after accounting for the isotopic change of sea-water. No correction for the influence of the geographical position of the ice was applied. Dust content: file "dustnat.txt" Column 1 -Ice Age (GT4) Column 2 – dust concentration in ppm The dust concentration was calculated from the total volume concentration (from Coulter counter measurements), and assuming a dust density of 2.500 Kg. m-3. Data from Petit et al (1990), Jouzel et al. (1993) down to 2545 m depth have been included. Sodium content file "nanat.txt" Column 1: Ice age (GT4 chronology) Column 2: Sodium concentration (ppb) Data from Legrand et al.(1988) ,down to 2080 m have been included. CH4 data: file"ch4nat.txt" Column 1: Gas Age as deduced from the Barnola et al. (1991) model Column 2: CH4 concentration (ppbv). See note below CO2 data: file"co2nat.txt" Column 1: Gas Age as deduced from the Barnola et al. (1991) model Column 2: CO2 concentration (ppmv). CO2 and CH4 measurements have been performed using the methods and analytical procedures previously described (Barnola et al., 1987, Chappellaz et al, 1990). However, the CO2 measuring system has been slightly modified in order to increase the sensitivity of the CO2 detection. The thermal conductivity chromatographic detector has been replaced by a flame ionisation detector which measures CO2 after its transformation into CH4. The overall accuracy for CH4 and CO2 measurements are ± 20 ppbv and 2-3 ppmv respectively. No gravitational correction has been applied. Atmospheric Oxygen : file "o18nat.txt" Column 1: Gas Age as deduced from the Barnola et al. (1991) model Column2: d18Oatm ‰ d18Oatm data published in Sowers et al.(1993) and Jouzel et al.(1993) have been included.