# Sacred Lake, Mt. Kenya 1800 Year Leaf Wax Deuterium and d13C Data #----------------------------------------------------------------------- # 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: http://ncdc.noaa.gov/paleo/study/17 ??? # # Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/eastafrica/sacred2014d13c.txt # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Paleolimnology #-------------------- # Contribution_Date # Date: 2015-01-28 #-------------------- # Title # Study_Name: Sacred Lake, Mt. Kenya 1800 Year Leaf Wax Deuterium and d13C Data #-------------------- # Investigators # Investigators: Konecky, B.; Russell, J.; Huang, Y.; Vuille, M.; Cohen, L.; Street-Perrott, F.A. #-------------------- # Description_and_Notes # Description: Leaf wax stable isotope (dD and d13C) from sediments collected in Sacred Lake, Mt. Kenya, # covering the past 1800 years. Dates on samples from Huang et al., 1999 have been updated to the age model # of Konecky et al., 2014. #-------------------- # Publication # Authors: Bronwen Konecky, James Russell, Yongsong Huang, Mathias Vuille, Lily Cohen, F. Alayne Street-Perrott # Published_Date_or_Year: 2014-02-15 # Published_Title: Impact of monsoons, temperature, and CO2 on the rainfall and ecosystems of Mt. Kenya during the Common Era # Journal_Name: Palaeogeography, Palaeoclimatology, Palaeoecology # Volume: 396 # Edition: # Issue: # Pages: 17-25 # DOI: 10.1016/j.palaeo.2013.12.037 # Online_Resource: http://www.sciencedirect.com/science/article/pii/S0031018213005749 # Full_Citation: # Abstract: Glacial and early Holocene-age sediments from lakes on Mt. Kenya have documented strong responses of montane hydrology, ecosystems, and carbon cycling to past changes in temperature and atmospheric CO2 concentrations. However, little is known about climate and ecosystem variations on Mt. Kenya during the Common Era (the past ~2000 years), despite mounting evidence for significant climate changes in the East African lowlands during the past millennium and recent observations of alpine glacier retreat in the East African highlands. We present a new, high-resolution record of the hydrogen and carbon isotopic composition of terrestrial plant wax compounds (dDwax, d13Cwax) preserved in the sediments of Sacred Lake from 200C.E. to the end of the 20th century. We find that Mt. Kenya's climate was highly variable during the past 1800 years. Droughts at Sacred Lake around ~200C.E., 700C.E., and 1100C.E. align with similar droughts in central Kenya and Uganda/Congo, indicating that failures of both the Indian and Atlantic monsoons caused widespread drought throughout equatorial East Africa during the early Common Era. In contrast, dry and wet periods at Sacred Lake during the past 500 years show meridional and zonal contrasts with other sites in East Africa, suggesting strong spatial heterogeneity, possibly due to independent waxing and waning of the Atlantic and Indian monsoons. Pronounced drying after ~1870C.E. suggests that the current dry phase observed at Sacred Lake may have begun prior to the 20th century, around the time when the retreat of Mt. Kenya's glaciers was first observed by European explorers. Mt. Kenya's vegetation responded strongly to these recent climate changes, highlighting the particular sensitivity of tropical montane climate and ecosystems to regional and global climate patterns, and underscoring the critical need to understand potential impacts of future climate change scenarios on this highly sensitive region. #------------------ # Publication # Authors: Yongsong Huang, F. Alayne Street-Perrott, R. Alan Perrott, Pierre Metzger, Geoffrey Eglinton # Published_Date_or_Year: 1999-05-01 # Published_Title: Glacial-interglacial environmental changes inferred from molecular and compound-specific d13C analyses of sediments from Sacred Lake, Mt. Kenya # Journal_Name: Geochimica et Cosmochimica Acta # Volume: 63 # Edition: # Issue: 9 # Pages: 1383-1404 # DOI: 10.1016/S0016-7037(00)00445-2 # Online_Resource: http://www.sciencedirect.com/science/article/pii/S0016703700004452 # Full_Citation: # Abstract: Mapping the abundance of 13C in leaf-wax components in surface sediments recovered from the seafloor off northwest Africa (0-35N) reveals a clear pattern of d13C distribution, indicating systematic changes in the proportions of terrestrial C3 and C4 plant input. At 20N latitude, we find that isotopically enriched products characteristic of C4 plants account for more than 50% of the terrigenous inputs. This signal extends westward beneath the path of the dust-laden Sahara Air Layer (SAL). High C4 contributions, apparently carried by January trade winds, also extend far into the Gulf of Guinea. Similar distributions are obtained if summed pollen counts for the Chenopodiaceae-Amaranthaceae and the Poaceae are used as an independent C4 proxy. We conclude that the specificity of the latitudinal distribution of vegetation in North West Africa and the pathways of the wind systems (trade winds and SAL) are responsible for the observed isotopic patterns observed in the surface sediments. Molecular-isotopic maps on the marine-sedimentary time horizons (e.g., during the last glacial maximum) are thus a robust tool for assessing the phytogeographic changes on the tropical and sub-tropical continents, which have important implications for the changes in climatic and atmospheric conditions. #------------------ # Funding_Agency # Funding_Agency_Name: US National Atmospheric and Oceanic Administration # Grant: NA090AR4310107, NA09OAR4310090 #------------------ # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: 1003690, Graduate Research Fellowship #------------------ # Site_Information # Site_Name: Sacred Lake # Location: Africa>Eastern Africa>Kenya # Country: Kenya # Northernmost_Latitude: 0.0833 # Southernmost_Latitude: 0.0833 # Easternmost_Longitude: 37.5333 # Westernmost_Longitude: 37.5333 # Elevation: 2350 m #------------------ # Data_Collection # Collection_Name: Sacred2014d13C # Earliest_Year: 113 # Most_Recent_Year: 1976 # Time_Unit: AD # Core_Length: m # Notes: #------------------ # Chronology: # # An age model for the full length of core SL1 (16.34 m; >40,000 years of sediment) was constructed using # a mixed effect regression model (Heegaard et al., 2005) based on 29 radiocarbon dates on bulk organic # matter (Loomis et al., 2012). Several substantial changes in sedimentation rate occur in deeper sections # of the core, the uppermost of which is around 365 cm depth. Because 14C ages in the upper 3 m of core # suggest much more linear sedimentation rates, and our samples extend only to 2.5 m, we constructed a new # age model for the upper 3 mof core using the 8 uppermost radiocarbon dates. We assume a core-top age # of 1989 C.E., the year of core collection. # #---------------- # Variables # # Data variables follow that are preceded by "##" in columns one and two. # Data line variables format: Variables list, one per line, shortname-tab-longname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) # ##depth_cm depth, , , cm below lake floor, , , , ,N ##age_AD age, , , AD, , , , ,N ##d13cleafwaxC28 delta 13C, leaf wax C-28 n-alkanoic acid, , per mil VPDB, , , , ,N ##d13cleafwaxC28corr delta 13C - Suess effect corrected, leaf wax C-28 n-alkanoic acid, , per mil VPDB, , , , ,N ##notes Notes - Source,,,,,,,,C # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # depth_cm age_AD d13cleafwaxC28 d13cleafwaxC28corr notes 1.5 1976 -31.3 -30.3 Konecky et al., 2013 2.5 1968 -33.2 -32.3 Huang et al., 1999 5.5 1943 -28.3 -27.7 Konecky et al., 2013 8.5 1918 -29.4 -29.0 Huang et al., 1999 9.5 1910 -28.4 -28.1 Konecky et al., 2013 11.5 1893 -29.7 -29.4 Konecky et al., 2013 14.5 1869 -28.0 -27.7 Konecky et al., 2013 16.5 1852 -27.2 -27.0 Konecky et al., 2013 19.5 1828 -27.2 -27.0 Konecky et al., 2013 22.5 1804 -27.5 -27.4 Konecky et al., 2013 27.5 1766 -26.6 -26.6 Konecky et al., 2013 30.5 1743 -26.7 -26.7 Konecky et al., 2013 38.5 1685 -28.8 -28.8 Konecky et al., 2013 45.5 1637 -26.5 -26.5 Konecky et al., 2013 51.5 1598 -27.5 -27.5 Konecky et al., 2013 62.3 1533 -27.4 -27.4 Konecky et al., 2013 82.3 1427 -27.4 -27.4 Konecky et al., 2013 92.3 1382 -26.6 -26.6 Konecky et al., 2013 103.7 1336 -26.6 -26.6 Konecky et al., 2013 120.9 1274 -27.1 -27.1 Konecky et al., 2013 138.0 1209 -26.9 -26.9 Konecky et al., 2013 151.3 1126 -27.8 -27.8 Konecky et al., 2013 161.5 1023 -27.1 -27.1 Konecky et al., 2013 171.8 892 -27.1 -27.1 Konecky et al., 2013 182.0 751 -27.8 -27.8 Konecky et al., 2013 193.4 606 -27.0 -27.0 Konecky et al., 2013 206.0 486 -28.7 -28.7 Konecky et al., 2013 220.8 389 -28.3 -28.3 Konecky et al., 2013 229.9 340 -27.8 -27.8 Konecky et al., 2013 262.5 113 -28.2 -28.2 Huang et al., 1999