# 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-t1.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 d18Otied Age Model R14 # Oldest_Year: 20690 # Most_Recent_Year: 7600 # Time_Unit: cal yrBP # Core_Length: # Notes: Table 1: age control points used in MD02-2489 d18O-tied age model. Control point codes: R=14C, T=Tie #-------------------------------- # 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 7.60 R1 Calib600, IntCal09, DR 450±100, Marine curve, 100% Marine 66.5 8.80 R2 Calib600, IntCal09, DR 450±100, Marine curve, 100% Marine 76.5 9.42 R3 Calib600, IntCal09, DR 450±100, Marine curve, 100% Marine 86.5 10.56 R4 Calib600, IntCal09, DR 450±100, Marine curve, 100% Marine 96 11.92 R5 Calib600, IntCal09, DR 450±100, Marine curve, 100% Marine 110 12.90 R6 Calib600, IntCal09, DR 450±100, Marine curve, 100% Marine 119 13.15 R7 Calib600, IntCal09, DR 450±100, Marine curve, 100% Marine 142 14.07 T1 Older Dryas tied with G.bull. excursion. Feature is broader in N.pachy. 167 14.64 T2 Bolling-Allerod tied with N.pachy. G.bull. signal likely smeared by bioturb, given increase in abundance at BA. 196 15.95 T3 Excursion in Stal tied with excursion in G.bull. 227 17.88 T4 Early HS1 NGRIP excurision - similar feature widely seen in N. Pacific. Use midpoint of initial change in G.bull. 246 18.45 T5 Step in NGRIP tied with step in G.bull. 288 20.69 T6 Excursion in ice cores and stal tied with excursion in N.pachy. Use midpoint of N.pachy excursion.