Vostok Data Set: Readme File
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World Data Center A- Paleoclimatology
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NOTE: PLEASE CITE ORIGINAL REFERENCES WHEN USING THIS DATA!!!!!
NAME OF DATA SET: Vostok Data Set
LAST UPDATE: 5/96 (Addition of vostok.dd, vostok.dst, vostok.time)
GEOGRAPHIC REGION: Antarctica
PERIOD OF RECORD: 0 - 240,000 YBP
LIST OF FILES: CH4.DAT, CO2.DAT, DUSTVOL.DAT, DUSTFLUX.DAT,
vostok.dd, vostok.dst, vostok.time, readme (this file).
CONTRIBUTORS: J. Chapellaz, Laboratoire de Glaciologie
et Geophysique de l'Environment, and Jean Jouzel, Grenoble.
IGBP PAGES/WDCA Data Contribution Series #: 92-018
SUGGESTED DATA CITATION:
Chapellaz, J. and J. Jouzel, 1992, Vostok Ice Core Data Set.
IGBP PAGES/World Data Center-A for Paleoclimatology
Data Contribution Series # 92-018. NOAA/NGDC Paleoclimatology Program,
Boulder CO, USA.
ORIGINAL REFERENCES:
Jouzel et al, Vostok ice core: A continuous isotope temperature record
over the last climatic cycle (160,000 years), Nature,329,6138,403-408
(1987)
Petit et al., Nature, 343,65253,56-58,1990)
C. Lorius, J. Jouzel, C. Ritz, L. Merlivat, N. I. Barkov, Y. S. Korotkevitch
and V. M. Kotlyakov, A 150,000-year climatic record from Antarctic ice, Nature,
316, 1985, 591-596.
J. Jouzel, C. Lorius, J. R. Petit, C. Genthon, N. I. Barkov, V. M. Kotlyakov
and V. M. Petrov, Vostok ice core: a continuous isotope temperature record over
the last climatic cycle (160,000 years), Nature, 329, 1987, 402-408.
J. R. Petit, L. Mounier, J. Jouzel, Y. Korotkevitch, V. Kotlyakov and C.
Lorius, Paleoclimatological implications of the Vostok core dust record,
Nature, 343, 1990, 56-58.
C. Ritz. Un modele thermo-mecanique d'evolution pour le bassin glaciaire
Antarctique Vostok-Glacier Byrd: sensibilite aux valeurs des parametres mal
connus (Univ. de Grenoble, 1992).
T. Sowers, M. Bender, L. D. Labeyrie, J. Jouzel, D. Raynaud, D. Martinson and
Y. S. Korotkevich, 135 000 year Vostok - SPECMAP common temporal framework.,
Paleoceanogr., 8, 1993, p. 737-766.
J. Jouzel, 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, Extending the Vostok
ice-core record of paleoclimate to the penultimate glacial period, Nature, 364,
1993, 407-412.
C. Waelbroeck, J. Jouzel, L. Labeyrie, C. Lorius, M. Labracherie, M. Stievenard
and N. I. Barkov, Comparing the Vostok ice deuterium record and series from
Southern Ocean core MD 88-770 over the last two glacial-interglacial cycles,
Clim. Dyn., 12, 1995, 113 - 123.
J. Jouzel, C. Waelbroeck, B. Malaiz, 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, Climatic interpretation of the recently extended Vostok ice
records, Clim.Dyn., In press
DESCRIPTION:
File: CH4.DAT
Contains depth, Age, and CH4 concentration.
File: CO2.DAT
Contains depth, age, CO2 concentration.
File: DUSTVOL.DAT
Contains depth, dust volume concentration
(in 10-9cm3 of dust per g of snow).
Insoluble microparticles published in Nature paper
(Petit et al.,343,65253, 56-58,1990)
File: DUSTFLUX.DAT
Contains age, flux (in milligrams of dust per year per square meter).
This was deduced from the published data assuming a dust density of
2, and is a more convenient value. Original data are smoothed using a
spline function.
File: vostok.dst
DUST: COLUMNS 7 AND 8
Column 7 gives the dust volume concentration in 10 -9 cm3 / g of ice as
published by Petit et al (1990) from 125 to 2202 m and by Jouzel et al. (1993)
between 2202 and 2541m.
Column 8 gives the number of dust particles larger than .8 m per g of ice
(Jouzel et al. 1996). As for deuterium measurements 3.41 m have been added to
the depth measured in the field for 5G samples (on this core measurements have
been done below 2500 m only).
Deuterium measurements have been performed on three adjacent cores 3G, 4G and
5G (see Figure 1 of Jouzel et al., 1996).
File: vostok.dd
Deuterium measurements have been performed on three adjacent cores 3G, 4G and
5G (see Figure 1 of Jouzel et al., 1996).
This file combines results successively published in Jouzel et al. (1987, 1993
and 1996).
Data are 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.
The depth indicated in column 1 corresponds to the middle of the increment
(mbs). For a given age there are slight depth differences between the three
cores (maximum of ~ 3 m) easily recognizable from core stratigraphy (e.g., ash
layers). Based on such observations 3.41 m have been added to the depth
measured in the field for 5G samples.
Deuterium values (column 7) have been measured on ice samples of length
comprised between 0.5 and 2 m and reinterpolated on 1m intervals afterwards.
The ice recovery is 85% or higher. Measurement accuracy is of ± 0.5ä SMOW (1
s). From the surface down to 7 m a constant value (derived from surface and
pits samples) of - 438.0 ä is reported .
The temperature change indicated in column 8 (temperature abobve the inversion)
corresponds to the corrected curve published in Jouzel et al. (1996). This
temperature is calculated using a deuterium / temperature gradient of 9ä/¡C
after accounting for the isotopic change of sea-water and applying a smoothing
procedure; this record is then corrected for the influence of the geographical
position of the precipitation site as described in Jouzel et al. (1996).
File: vostok.time
Different timescales have been used for the interpretation of Vostok
ice core records. They are reported in ky BP.
- The Lorius et al. timescale (column 2) has been derived by combining
a glaciological model, fully described in Ritz (1992) and an accumulation model
in which past accumulation is derived from the temperature record reconstructed
from the deuterium isotopic profile (see Lorius et al., 1985).
- Sowers et al. correlated the d18O of paleoatmospheric O2 derived from
the Vostok 3G and 4G cores, into a record of changes in the d18O of sea water
derived from records of the d18O of foraminifera (see Sowers et al., 1993).
This timescale is given in column 3.
- The glaciological timescale of Lorius et al. (1985) has been extended
accounting for a linear increase of modern accumulation upstream of Vostok.
This Extended Glaciological Timescale (EGT; column 4) is described in Jouzel et
al. (1993).
- Jouzel et al. (1996) have used a modified version of EGT (column 4)
assuming that this timescale overestimates the increase of age with depth by
12% for gas ages older than 112 ky BP.
- Waelbroeck et al. (1995) have applied the orbital tuning approach to
the deuterium record to derive a timescale which is consistent with the SPECMAP
marine timescale. This orbitally derived timescale is given in column 6.
IMPORTANT NOTE: because of filtering errors due to the finite length of the
record, the upper and bottom 20 to 35 ky of the orbitally tuned chronology can
not be trusted. In the present file, the upper 35 ky of the orbitally tuned
chronology have been replaced by the EGT timescale.