# Polar Ice Core 42-77ka Excess Methane Data #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 3.0 # Encoding: UTF-8 # NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. # If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/27610 # Description: NOAA Landing Page # Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/lee2020ch4-gisp2.txt # Description: NOAA location of the template # # Original_Source_URL: # Description: # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Ice Core # # Dataset DOI: # # Parameter_Keywords: atmospheric gas, instrumental data #-------------------- # Contribution_Date # Date: 2020-01-02 #-------------------- # File_Last_Modified_Date # Date: 2020-01-02 #-------------------- # Title # Study_Name: Polar Ice Core 42-77ka Excess Methane Data #-------------------- # Investigators # Investigators: Lee, J.E.; Edwards, J.S.; Schmitt, J.; Fischer, H.; Bock, M.; Brook, E.J. #-------------------- # Description_Notes_and_Keywords # Description: All GISP2 CH4 measurements presented in Lee et al. (2020, GCA). Includes previously published as well as unpublished values. Additional citations for data include: # - Brook et al. (2000) "On the origin and timing of rapid changes in atmospheric methane during the last glacial period." Global Biogeochemical Cycles, 14 (2), 559-572. # -The original data were on the old NOAA CMDL concentration scale. # -Corrected concentrations are given following Dlucockency et al. (2005) to put the concentrations on the NOAA04 scale. # -These measurements were made at URI and WSU # -No solubility correction # -In the original archived data set several duplicate of measurement were not averaged. # - Brook et al. (2005) "Timing of millennial-scale climate change at Siple Dome, West Antarctica, during the last glacial period." Quaternary Science Review, 24, 1333-1343. # -Data from WSU # -Measured on old NOAA Scale # -Corrected concentrations are given following Dlucockency et al. (2005) to put the concentrations on the NOAA04 scale. # -No solubility correction # - New (Lee et al., 2020) # -Measured on NOAA04 scale using new OSU methods # -Solubility correction from Mitchell et al. (2011). # #-------------------- # Publication # Authors: James E. Lee, Jon S. Edwards, Jochen Schmitt, Hubertus Fischer, Michael Bock, Edward J. Brook # Published_Date_or_Year: 2020-02-01 # Published_Title: Excess methane in Greenland ice cores associated with high dust concentrations # Journal_Name: Geochemica et Cosmochemica Acta # Volume: 270 # Edition: # Issue: # Pages: 409-430 # Report_Number: # DOI: 10.1016/j.gca.2019.11.020 # Online_Resource: https://www.sciencedirect.com/science/article/pii/S0016703719307288 # Full_Citation: # Abstract: Ice core records of atmospheric methane (CH4) and its isotopic composition provide important information about biogeochemical cycles in the past. Interpreting these data requires that they faithfully record the composition of the atmosphere. In this study, we describe anomalies of up to 30-40 ppb CH4 that are only observed in dust-rich (>~60 ng Ca/g ice), glacial-period ice measured with standard melt-refreeze methods. The stable isotopic composition of CH4 is also significantly affected. Results from the GISP2 and NEEM ice cores from Greenland show that excess CH4 is either released or produced in the presence of liquid water in amounts which are highly correlated with the abundance of Ca2+ and mineral dust in the sample. Additional experiments show that excess CH4 is unaffected by the addition of HgCl2 (a microbial inhibitor) and is not related to ice core storage time. Dust concentrations in Antarctic ice cores are an order of magnitude lower than in Greenlandic ice cores and no excess CH4 was observed in samples from the Antarctic WAIS Divide (WD) and South Pole (SPICE) ice cores. While the overall structure of the ice core atmospheric methane history is minimally impacted by excess CH4, the impacts on the isotopic record and on inverse models used to reconstruct CH4 sources are greater. We propose three potential mechanisms to explain the presence of excess CH4: (1) that CH4 is adsorbed on dust particles prior to deposition on the ice sheet and is slowly desorbed during the melt-extraction step of sample analysis; (2) that dust acts as a micro-environment within the ice sheet for methanogenic extremophiles; or (3) that excess CH4 is a product of abiotic degradation of organic compounds during the melt-extraction step of sample analysis. #------------------ # Funding_Agency # Funding_Agency_Name: US National Science Foundation PIRE # Grant: 0968391 #------------------ # Funding_Agency # Funding_Agency_Name: European Research Council (ERC) # Grant: 226172 #------------------ # Funding_Agency # Funding_Agency_Name: Swiss National Science Foundation # Grant: #--------------------------------------- # Site Information # Site_Name: GISP2 # Location: North America>Greenland # Country: # Northernmost_Latitude: 72.6 # Southernmost_Latitude: 72.6 # Easternmost_Longitude: -38.5 # Westernmost_Longitude: -38.5 # Elevation: 3200 m #--------------------------------------- # Data_Collection # Collection_Name: Lee2020CH4 # Earliest_Year: 76829 # Most_Recent_Year: 22365 # Time_Unit: Cal. Year BP # Core_Length: # Notes: #------------------ # Chronology_Information # Chronology: Gas ages for samples are provided on GICC05 Age Scale (Rasmussen et al. (2014), "A stratigraphic framework for abrupt climatic changes during the Last Glacial period based on three synchronized Greenland ice-core records: refining and extending the INTIMATE event stratigraphy." # Quaternary Science Reviews 106, 14-28.; Seierstad et al. (2014), "Greenland GRIP, GISP2 and NGRIP ice cores for the past 104 ka reveal regional millennial-scale d18Ogradients with possible Heinrich event imprint." Quaternary Science Reviews 106, 29-46.) #---------------- # Variables # # Data variables follow are preceded by "##" in columns one and two. # Data line variables format: one per line, shortname-tab-variable components (what, material, error, units, seasonality, data type,detail, method, C or N for Character or Numeric data, free text) # # Top_Depth Sample Top Depth,,,meter,,,,,N,mean depth below surface of typically 10 cm long samples # Gas_Age Age,gas,,year Before Present,,,,,N,Gas Age of Top Depth before 1950 CE # CH4_primary methane,,,parts per billion,,ice core,,,N,mean [CH4] value of first measurement set # Source Source,,,,,,C,,,Citation for data # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # Top_Depth Gas_Age CH4_primary Source 2188.1 35331 590.2 Brook et al. (2001) 2195.1 35749 449.5 Brook et al. (2001) 2202 36314 466.7 Brook et al. (2001) 2208 36680 539.6 Brook et al. (2001) 2210 36790 506.2 Brook et al. (2001) 2215.1 37070 584.2 Brook et al. (2001) 2218 37199 578.1 Brook et al. (2001) 2220 37294 561.9 Brook et al. (2001) 2222 37384 585.2 Brook et al. (2001) 2224 37467 560.9 Brook et al. (2001) 2226 37543 568 Brook et al. (2001) 2228.1 37625 578.1 Brook et al. (2001) 2229.9 37688 566.9 Brook et al. (2001) 2232 37769 591.2 Brook et al. (2001) 2232.9 37801 582.1 Brook et al. (2001) 2234 37836 566.9 Brook et al. (2001) 2235 37866 630.7 Brook et al. (2001) 2236 37896 578.1 Brook et al. (2001) 2237 37925 593.3 Brook et al. (2001) 2238.9 37987 589.2 Brook et al. (2001) 2240 38023 612.5 Brook et al. (2001) 2240.9 38056 602.4 Brook et al. (2001) 2242 38094 617.6 Brook et al. (2001) 2242.5 38113 584.2 Brook et al. (2001) 2243 38136 591.2 Brook et al. (2001) 2243.5 38162 606.4 Brook et al. (2001) 2244 38189 556.8 Brook et al. (2001) 2244.5 38229 513.3 Brook et al. (2001) 2245 38278 492 Brook et al. (2001) 2245.5 38329 543.7 Brook et al. (2001) 2246 38376 471.8 Brook et al. (2001) 2247.6 38499 459.3 Lee et al. (2020) 2248.6 38583 462.5 Lee et al. (2020) 2251.2 38812 461.1 Lee et al. (2020) 2253.1 38965 452.6 Lee et al. (2020) 2254.3 39077 447 Lee et al. (2020) 2254.9 39148 444.4 Lee et al. (2020) 2255.4 39202 443.6 Lee et al. (2020) 2257.1 39388 460.3 Lee et al. (2020) 2257.9 39478 441.1 Lee et al. (2020) 2258.5 39536 429.2 Lee et al. (2020) 2260.1 39663 430.2 Lee et al. (2020) 2261.1 39740 424.3 Lee et al. (2020) 2262.6 39843 435.3 Lee et al. (2020) 2263.6 39896 427.5 Lee et al. (2020) 2265 39973 477 Lee et al. (2020) 2266.9 40064 477.7 Lee et al. (2020) 2268.1 40154 432.6 Lee et al. (2020) 2269.1 40253 423.9 Lee et al. (2020) 2270.1 40347 426.9 Lee et al. (2020) 2271.6 40479 428.9 Lee et al. (2020) 2273.1 40600 434.3 Lee et al. (2020) 2274.1 40692 437.9 Lee et al. (2020) 2275.1 40782 448.2 Lee et al. (2020) 2276.1 40859 451.7 Lee et al. (2020) 2277.1 40927 491.6 Lee et al. (2020) 2278.6 40993 508.4 Lee et al. (2020) 2280.1 41046 492.2 Lee et al. (2020) 2282.1 41116 508.6 Lee et al. (2020) 2284.1 41189 503.7 Lee et al. (2020) 2286.1 41305 510.3 Lee et al. (2020) 2289.1 41628 417.3 Lee et al. (2020) 2291.2 41889 424.4 Lee et al. (2020) 2293.6 42163 427.1 Lee et al. (2020) 2296.1 42343 463.9 Lee et al. (2020) 2298.6 42508 475.1 Lee et al. (2020) 2301.1 42657 496.6 Lee et al. (2020) 2304.1 42830 517.3 Lee et al. (2020) 2307.1 42973 509.8 Lee et al. (2020) 2309.6 43076 515.4 Lee et al. (2020) 2312.1 43197 516.5 Lee et al. (2020) 2313.6 43280 515 Lee et al. (2020) 2315.1 43410 426.4 Lee et al. (2020) 2316.2 43549 419.9 Lee et al. (2020) 2318.1 43802 425.1 Lee et al. (2020) 2319.9 44003 419.1 Brook et al. (2001) 2323.9 44334 439.4 Brook et al. (2001) 2325.9 44453 479.9 Brook et al. (2001) 2327.9 44620 444.4 Brook et al. (2001) 2330 44776 475.8 Brook et al. (2001) 2331.9 44910 436.3 Brook et al. (2001) 2333.9 45041 478.9 Brook et al. (2001) 2335.9 45172 503.2 Brook et al. (2001) 2337.9 45304 483.9 Brook et al. (2001) 2339.9 45427 483.9 Brook et al. (2001) 2341.9 45540 488 Brook et al. (2001) 2343.9 45646 493 Brook et al. (2001) 2345.9 45761 520.4 Brook et al. (2001) 2347.9 45888 497.1 Brook et al. (2001) 2349.9 46003 495.1 Brook et al. (2001) 2351.9 46118 540.6 Brook et al. (2001) 2354.1 46230 498.7 Brook et al. (2005) 2358.2 46424 530.5 Brook et al. (2005) 2359.2 46474 529.4 Brook et al. (2005) 2360.2 46507 519.5 Brook et al. (2005) 2361 46531 532.4 Brook et al. (2005) 2361.4 46544 513.5 Brook et al. (2005) 2362.2 46568 550.9 Brook et al. (2005) 2362.3 46571 528.8 Brook et al. (2005) 2363.3 46599 541.2 Brook et al. (2005) 2364.3 46632 525.7 Brook et al. (2005) 2364.7 46648 533.7 Brook et al. (2005) 2365.3 46674 544.1 Brook et al. (2005) 2365.8 46697 535.8 Brook et al. (2005) 2366.2 46719 561.4 Brook et al. (2005) 2366.3 46724 569.1 Brook et al. (2005) 2366.7 46746 530.6 Brook et al. (2005) 2366.8 46752 568.9 Brook et al. (2005) 2367.2 46776 557.5 Brook et al. (2005) 2367.4 46789 545.2 Brook et al. (2005) 2367.6 46801 561.5 Brook et al. (2005) 2367.8 46815 554.2 Brook et al. (2005) 2368.2 46845 588.9 Brook et al. (2005) 2368.3 46852 509 Brook et al. (2005) 2368.7 46888 475.1 Brook et al. (2005) 2368.8 46898 459.7 Brook et al. (2005) 2370.2 47068 492.8 Brook et al. (2005) 2370.3 47079 455 Brook et al. (2005) 2370.7 47127 469.5 Brook et al. (2005) 2370.8 47139 465.2 Brook et al. (2005) 2371.4 47213 472.4 Brook et al. (2005) 2371.9 47271 536.4 Brook et al. (2005) 2372.2 47303 472.4 Brook et al. (2005) 2372.3 47314 476.1 Brook et al. (2005) 2372.7 47354 448.1 Brook et al. (2005) 2372.8 47365 451.3 Brook et al. (2005) 2373.2 47404 466.8 Brook et al. (2005) 2373.3 47414 467.3 Brook et al. (2005) 2373.7 47456 447.7 Brook et al. (2005) 2373.8 47470 453.4 Brook et al. (2005) 2374.2 47519 431.3 Brook et al. (2005) 2374.8 47589 436.9 Brook et al. (2005) 2378 47999 459.6 Brook et al. (2001) 2383.9 48576 455.6 Brook et al. (2001) 2399.9 49788 492 Brook et al. (2001) 2405.9 50269 467.7 Brook et al. (2001) 2409.9 50563 488 Brook et al. (2001) 2416 51063 521.4 Brook et al. (2001) 2421.9 51519 507.2 Brook et al. (2001) 2425.9 51830 533.5 Brook et al. (2001) 2431.9 52249 542.6 Brook et al. (2001) 2437.9 52683 554.8 Brook et al. (2001) 2441.9 52947 554.8 Brook et al. (2001) 2453.9 53746 546.7 Brook et al. (2001) 2458 53991 561.9 Brook et al. (2001)