noaa-icecore-17801 GISP2 Ice Core 17KYr In-situ 14C Data Lal, D.; Jull, A.J.T.; Burr, G.S.; Donahue, D.J. GISP2 Ice Core 17KYr In-situ 14C Data 1997-11-30 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/17801 Investigator D. Lal Investigator A.J.T. Jull Investigator G.S. Burr Investigator D.J. Donahue earth science paleoclimate ice cores depth at sample start,null,null,meter,null,ice cores,null,null,N,null earth science paleoclimate ice cores accumulation rate,bulk ice,null,centimeter per year,null,ice cores,null,null,N,null earth science paleoclimate ice cores 14C,carbon dioxide,unspecified margin of error,count per gram,null,ice cores,null,accelerator mass spectrometry,N,atom per gram earth science paleoclimate ice cores 14C,null,null,dimensionless,null,ice cores,null,null,N,Approximate fraction 14C from in-situ production during storage. earth science paleoclimate ice cores depth at sample end,null,null,meter,null,ice cores,null,null,N,null earth science paleoclimate ice cores 14C,carbon dioxide,null,count per gram,null,ice cores,null,null,N,Total: Decay-corrected 14C; atom per gram earth science paleoclimate ice cores 14C,carbon dioxide,unspecified margin of error,count per gram,null,ice cores,null,null,N,Total: Decay-corrected 14C; atom per gram earth science paleoclimate ice cores 14C,carbon monoxide,null,count per gram,null,ice cores,null,accelerator mass spectrometry,N,atom per gram earth science paleoclimate ice cores 14C,carbon dioxide,null,count per gram,null,ice cores,null,null,N,the amount of trapped 14CO2 is estimated from the amount of air in the ice (see Table 1) and assuming 250 ppm CO2 in air; constant thickness model; atom per gram earth science paleoclimate ice cores weight,bulk ice,null,kilogram,null,ice cores,null,null,N,null earth science paleoclimate ice cores 14C,carbon dioxide,null,count per gram,null,ice cores,null,accelerator mass spectrometry,N,atom per gram earth science paleoclimate ice cores depth,null,null,meter,null,ice cores,null,null,N,null earth science paleoclimate ice cores 14C,carbon dioxide,null,count per gram,null,ice cores,null,null,N,In situ produced: Decay-corrected 14C; atom per gram earth science paleoclimate ice cores accumulation rate,bulk ice,unspecified margin of error,centimeter per year,null,ice cores,null,null,N,null earth science paleoclimate ice cores air content,bulk ice,null,cubic centimeter per liter,null,ice cores,null,null,N,null earth science paleoclimate ice cores age,null,null,calendar year before present,null,ice cores,null,null,N,null earth science paleoclimate ice cores 14C,carbon monoxide,unspecified margin of error,count per gram,null,ice cores,null,accelerator mass spectrometry,N,atom per gram earth science paleoclimate ice cores 14C,carbon dioxide,unspecified margin of error,count per gram,null,ice cores,null,null,N,In situ produced: Decay-corrected 14C; atom per gram earth science paleoclimate ice core radiogenic isotopes geoscientificInformation 16200 cal yr BP 50 cal yr BP Complete 72.6 72.6 -38.5 -38.5 3200 3200 Continent North America Greenland GISP2>LATITUDE 72.6>LONGITUDE -38.5 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII D. Lal, A. J. T. Jull, G. S. Burr, D. J. Donahue 1997 Journal of Geophysical Research: Oceans 102 C12 26505-26510 10.1029/96JC02224 http://onlinelibrary.wiley.com/enhanced/doi/10.1029/96JC02224/

We present results of measurements of 14C in CO and CO2 phases for selected Greenland Ice Sheet Project 2 firn and ice samples up to a depth of 1838 m (16.6 kyr B.P.). The results show that 14C in ice consists of both in situ-produced cosmogenic 14C, which can be either in the form of CO or CO2, and trapped atmospheric 14CO2. In agreement with our previous work on studies of 14C concentrations in Antarctic firn and ice samples and some GISP2 samples, we found that the cosmogenic in situ-produced 14C (from spallation of oxygen nuclei) is greater than the trapped atmospheric 14C component. Also, we can show the total 14C amounts in ice are consistent with an efficient retention of the in situ variety of 14C in older ice where we expect lower average temperatures at the time of formation. The firn samples appear to have lost much of the 14C, probably during storage. The ice accumulation rates are estimated after due corrections for the CO2 content of trapped air and "secondary" 14C production in ice during storage at altitude. These values are in good accord with the recent model estimates of Cutler et al. [1995], except for two samples, at depths 1518.5 m (9740 years B.P.) and 1698.5 m (12,360 years B.P.). In the first case, the in situ 14C concentration is significantly higher than that predicted by either of the models, by a factor of about 2. In the second case, the estimate of Cutler et al. [1995] is a ~50% lower accumulation rate, but the 14C result is consistent with adjacent samples. A possible reason for the first discrepancy may be the decreased atmospheric pressure at that time at the site, as suggested by D. Raynaud et al. (unpublished manuscript, 1995). STUDY NOTES: 14C concentrations in CO and CO2 for selected depths in the GISP2 ice core

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/cosmoiso/c14c.txt Data File; GISP2 14-C Table 3 GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/cosmoiso/c14a.txt Data File; GISP2 14-C Table 1 GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/cosmoiso/c14b.txt Data File; GISP2 14-C Table 2 USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11