#----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # 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/15976 # Online_Resource: ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/eastafrica/tana2014deterium.txt # Online_Resource: ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/eastafrica/tana2014d13c.txt # Online_Resource: ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/eastafrica/tana2014.xls # # Original_Source_URL: # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Paleolimnology #-------------------- # Contribution_Date # Date: 2013-12-2014 #-------------------- # Title # Study_Name: Isotopic reconstruction of the African Humid Period and Congo Air Boundary migration at Lake Tana, Ethiopia #-------------------- # Investigators # Investigators: Costa,K.;Russel,J.;Konecky,B.L.;Lamb,H.F.; #-------------------- # Description_and_Notes # Description: δD of the C28 n-alkanoic acid (δDwax) fromcore 03TL3 taken from Lake Tana, Ethiopia (12 N, 37.25 E, 1830m) in 2007. Keywords - Tropical paleoclimate, East Africa, Compound specific hydrogen isotopes, African Humid Period, Holocene paleoclimate, Air mass trajectories, Congo Air Boundary, Tropics, Hydrology, Intertropical Convergence Zone (ITCZ), Abrupt climate change, Precipitation, Hydrogen isotopes, Carbon isotopes. #-------------------- # Publication # Authors: Costa, K., Russell, J., Konecky, B., Lamb, H. # Published_Date_or_Year: 2014 # Published_Title: Isotopic reconstruction of the African Humid Period and Congo Air Boundary migration at Lake Tana, Ethiopia # Journal_Name: Quaternary Science Reviews # Volume: Quaternary Science Reviews # Edition: # Issue: # Pages: 58-67 # Report_Number: # DOI: http://dx.doi.org/10.1016/j.quascirev.2013.10.031 # Publication_Place: # Publisher: # ISBN: # Online_Resource: # Other_Reference_Details: # Full_Citation: # Abstract: The African Humid Period of the early to mid-Holocene (12,000e5000 years ago) had dramatic ecological and societal consequences, including the expansion of vegetation and civilization into the “green Sahara.” While the humid period itself is well documented throughout northern and equatorial Africa, mechanisms behind observed regional variability in the timing and magnitude of the humid period remain disputed. This paper presents a new hydrogen isotope record from leaf waxes (dDwax) in a 15,000-year sediment core from Lake Tana, Ethiopia (12°N, 37°E) to provide insight into the timing, duration, and intensity of the African Humid Period over northeastern Africa. dDwax at Lake Tana ranges between 80‰ and 170 ‰, with an abrupt transition from D-enriched to D-depleted waxes between 13,000 e11,500 years before present (13e11.5 ka). A similarly abrupt transition from D-depleted to D-enriched waxes occurs ca 8.5e8 ka and is followed by generally D-enriched waxes throughout the late Holocene. Trends in dDwax covary with changes in Northern Hemisphere summer insolation and reflect increased precipitation at Lake Tana during the AHP; however, the transition from D-depleted to D-enriched waxes occurs earlier at Lake Tana (ca 8 ka, vs 5 ka) than in many other regional records, and the amplitude of Ddepletion during the AHP is larger at Lake Tana as well.We attribute this early enrichment to a reduction of moisture derived from westerly sources (the Congo Basin and Atlantic Ocean) which we suggest are Ddepleted relative to moisture sourced from the east (Indian Ocean) and the north (Red Sea and Mediterranean Sea). Our new record highlights the importance of both the northward migration of the tropical rain belt as well as east-west migration of the Congo Air Boundary to precipitation source and amount during the African Humid Period. #------------------ # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: #------------------ # Site_Information # Site_Name: Tana Lake # Location: Africa>East Africa>Ethiopia # Region: East Africa # Country: Ethiopia # Northernmost_Latitude: 12 # Southernmost_Latitude: 12 # Easternmost_Longitude: 37.25 # Westernmost_Longitude: 37.25 # Elevation: 1830 #------------------ # Data_Collection # Collection_Name: 03TL3-d13c # Earliest_Year: 14999 # Most_Recent_Year: 1390 # Time_Unit: cal yr BP # Core_Length: # Notes: #------------------ # Species: #------------------ # Chronology: #---------------- # Variables # Short_name What,Material,Error,Units, Seasonality,Archive,Details,Method,Data_type ## depth_cm Depth,,,cm,,,,,N ## age_BP Age,,,years BP,,,,,N ## d13Cleafwax Delta13C,leafwax,,per mil PDB,,Paleolimnology,,,N ## d13Cleafwaxerror Delta13C,leafwax,two sigma,per mil PDB,,Paleolimnology,,,N #---------------- # Data # Missing_Values: NA depth_cm age_BP d13Cleafwax d13Cleafwaxerror 133 1390 -23.43 0.11 168 1755 -27.30 -0.27 213 2215 -26.15 -0.05 238 2465 -24.37 -0.23 272 2805 -24.74 NA 322 3354 -26.32 -0.03 347 3706 -29.96 0.13 368 4003 -23.67 0.02 382 4201 -26.27 0.06 398 4486 -26.85 0.14 415 4807 -26.36 -0.11 456 5580 -25.60 -0.06 499 6570 -27.22 0.44 514 6936 -26.75 -0.15 526 7250 -24.10 0.06 549 7851 -26.64 0.07 576 8561 -27.33 0.01 585 8806 -26.29 0.03 606 9377 -25.73 -0.39 630 10029 -25.80 -0.33 644 10405 -25.31 0.35 659 10794 -25.81 -0.21 692 11617 -25.79 -0.33 713 12050 -27.47 0.08 742 12578 -27.63 0.10 776 13198 -27.34 0.30 799 13618 -29.42 -0.08 812 13802 -25.80 0.33 859 14420 -28.01 0.01 911 14999 -29.83 0.08