# Deglacial North East Pacific Radiocarbon and Boron Isotope Data from MD02-2489 #----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Online_Resource: http://www.ncdc.noaa.gov/paleo/study/16648 # # Online_Resource: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/rae2014/rae2014-t2.txt # # Archive: Paleoceanography # #-------------------------------- # Contribution_Date # Date: 2014-06-18 #-------------------------------- # Title: Deglacial North East Pacific Radiocarbon and Boron Isotope Data from MD02-2489 #-------------------------------- # Investigators: Rae, J.W.B.; Sarnthein, M.; Foster, G.L.; Ridgwell, A.; Grootes, P.M.; Elliott, T. #-------------------- # Description and Notes: # The data given here include age models, boron isotope data analysed by MC-ICPMS, and radiocarbon data analysed by AMS. # # Keywords from PI: Radiocarbon; Boron isotopes; North Pacific; Deglacial CO2; Deep water formation; #-------------------- # Publication # Authors: Rae, J.W.B., M. Sarnthein, G.L. Foster, A. Ridgwell, P.M. Grootes, and T. Elliott # Journal_Name: Paleoceanography # Published_Title: Deep water formation in the North Pacific and deglacial CO2 rise # Published_Date_or_Year: 2014 # Volume: # Pages: # DOI: 10.1002/2013PA002570 # Abstract: Deep water formation in the North Atlantic and Southern Ocean is widely thought to influence deglacial CO2 rise and climate change; here we suggest that deep water formation in the North Pacific may also play an important role. We present paired radiocarbon and boron isotope data from foraminifera from sediment core MD02-2489 at 3640 m in the North East Pacific. These show a pronounced excursion during Heinrich Stadial 1, with benthic-planktic radiocarbon offsets dropping to ~350 years, accompanied by a decrease in benthic δ11B. We suggest this is driven by the onset of deep convection in the North Pacific, which mixes young shallow waters to depth, old deep waters to the surface, and low-pH water from intermediate depths into the deep ocean. This deep water formation event was likely driven by an increase in surface salinity, due to subdued atmospheric/monsoonal freshwater flux during Heinrich Stadial 1. The ability of North Pacific Deep Water (NPDW) formation to ex plain the excursions seen in our data is demonstrated in a series of experiments with an intermediate complexity Earth system model. These experiments also show that breakdown of stratification in the North Pacific leads to a rapid ~30 ppm increase in atmospheric CO2, along with decreases in atmospheric δ13C and Δ14C, consistent with observations of the early deglaciation. Our inference of deep water formation is based mainly on results from a single sediment core, and our boron isotope data are unavoidably sparse in the key HS1 interval, so this hypothesis merits further testing. However we note that there is independent support for breakdown of stratification in shallower waters during this period, including a minimum in δ15N, younging in intermediate water 14C, and regional warming. We also re-evaluate deglacial changes in North Pacific productivity and carbonate preservation in light of our new data, and suggest that the regional pulse of export production observe d during the Bølling-Allerød is promoted by relatively stratified conditions, with increased light availability and a shallow, potent nutricline. Overall, our work highlights the potential of NPDW formation to play a significant and hitherto unrealized role in deglacial climate change and CO2 rise. #-------------------------------- # Funding_Agency: # Funding_Agency_Name: Natural Environment Research Council # Grant: NE/I017240/1, NE/C00876X/2 #-------------------------------- # Funding_Agency: # Funding_Agency_Name: NOAA/UCAR Climate and Global Change Postdoctoral Fellowship Program # Grant: #-------------------------------- # Funding_Agency: # Funding_Agency_Name: Deutsche Forschungsgemeinschaft # Grant: #-------------------------------- # Site Information: # Site_Name: MD02-2489 # Location: Eastern Pacific Ocean # Northernmost_Latitude: 54.39 # Southernmost_Latitude: 54.39 # Easternmost_Longitude: -148.92 # Westernmost_Longitude: -148.92 # Elevation: -3640 #-------------------------------- # Data Collection # Collection_Name: MD02-2489 Table2 Plateau-tuned R14 # Oldest_Year: 19000 # Most_Recent_Year: 7800 # Time_Unit: cal yrBP # Core_Length: # Notes: Table 2: age control points used in MD02-2489 14C-plateau-tuned age model, following approach of Sarnthein et al. 2007, and as given by Sarnthein et al. 2013. #-------------------------------- # Chronology: # #-------------------------------- # Variables # # Data variables follow (have double marker- "##") # Data line variables format: Variables list, one per line, shortname-tab-nine components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## depth_cm depth,,,cm,,,,,N ## age_calkaBP age,,,calendar kyr before 1950AD,,,,,N ## notes notes,,, ,,,,,C # Data: # Missing Value: depth_cm age_calkaBP notes 59.0 7800 intcal04 66.5 9020 intcal04 76.5 9550 intcal04 86.5 10770 intcal04 96.0 12570 intcal04 110.0 13170 intcal04 119.0 13350 intcal04 130.0 14050 plateau1 top 165.5 14900 plateau1 base 171.5 15250 plateau2a top 189.5 16050 plateau2a/plateau2b 200.5 16400 plateau2b base 208.0 16900 plateau3 top 219.0 17300 plateau3 base 231.0 18000 plateau4 top 250.0 19000 plateau4 base