# 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/17919 # # Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/eastafrica/sacred2014dd.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: Sacred2014dD # Earliest_Year: 211 # Most_Recent_Year: 1985 # 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 ##d2HleafwaxC28 delta2H, leaf wax C-28 n-alkanoic acid, , per mil VSMOW, , , , ,N ##d2HleafwaxC28diff delta2H difference, leaf wax C-28 n-alkanoic acid, , per mil VSMOW, , , difference of duplicate measurements, ,N ##d2HleafwaxC28std delta2H standard deviation, leaf wax C-28 n-alkanoic acid, , per mil VSMOW, , , standard deviation of triplicate measurements, ,N # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # depth_cm age_AD d2HleafwaxC28 d2HleafwaxC28diff d2HleafwaxC28std 0.5 1985 -103.341 0.477 1.5 1976 -100.575 2.091 3.5 1960 -104.309 1.77 4.5 1951 -117.579 0.901 5.5 1943 -120.328 1.197 7.5 1926 -117.935 2.313 9.5 1910 -119.134 0.047 10.5 1901 -111.931 0.604 11.5 1893 -107.184 2.765 12.5 1885 -118.688 0.014 14.5 1869 -130.926 0.09 15.5 1860 -131.524 1.356 16.5 1852 -131.609 1.09 17.5 1844 -130.965 1.278 18.5 1836 -136.612 2.744 19.5 1828 -129.779 0.998 20.5 1820 -132.199 1.444 21.5 1812 -132.493 0.206 22.5 1804 -134.629 2.553 25.5 1781 -133.814 0.011 26.5 1773 -136.655 1.609291873 27.5 1766 -133.410 0.623 28.5 1758 -135.050 0.669 29.5 1751 -131.905 1.725 30.5 1743 -133.661 0.007 31.5 1736 -135.792 0.609 32.5 1728 -134.723 0.529 33.5 1721 -133.196 1.208 35.5 1707 -134.200 1.555 36.5 1699 -135.757 2.025 37.5 1692 -123.555 0.951 38.5 1685 -123.069 0.313 39.5 1678 -122.561 0.746 41.5 1664 -118.968 0.478 45.5 1637 -133.068 0.437 46.5 1631 -133.059 0.833 47.5 1624 -130.263 0.564 48.5 1618 -128.654 1.578 49.5 1611 -125.185 1.69 50.5 1605 -127.878 0.67 51.5 1598 -130.554 0.003 57.965 1558 -130.083 1.308 62.255 1533 -123.854 2.68 65.115 1516 -129.307 0.718 70.835 1485 -133.739 1.793 75.125 1462 -133.701 0.395 82.275 1427 -132.807 2.767 83.705 1420 -130.232 0.649 86.565 1407 -133.654 0.237 90.855 1388 -138.295 0.069 92.285 1382 -132.254 1.323 95.145 1370 -138.202 1.049 99.435 1352 -132.088 1.704 100.865 1347 -132.600 1.123 103.725 1336 -133.751 0.393 109.445 1314 -137.625 0.878 112.305 1304 -135.605 1.378 118.025 1284 -135.389 0.129 120.885 1274 -135.416 0.402 125.175 1259 -130.179 2.425712473 126.605 1254 -134.754 2.047 129.465 1244 -136.658 0.634 138.045 1209 -136.927 0.48 142.335 1186 -131.729 0.15 143.765 1178 -132.513 2.227 146.625 1160 -136.011 0.579 151.25 1126 -126.682 0.847 152.39 1116 -127.479 1.748 154.67 1096 -131.560 2.357295908 159.23 1049 -134.117 0.673 161.51 1023 -135.690 2.118 164.93 982 -134.689 1.162 166.07 968 -134.387 1.94 168.35 938 -133.402 2.678 171.77 892 -130.459 1.906 172.91 877 -130.336 1.611372396 175.19 845 -125.287 1.891165337 179.75 783 -126.866 1.48 182.03 751 -125.010 0.098 186.59 691 -124.644 2.115256249 188.87 661 -118.533 1.104 192.29 620 -117.921 2.06 193.43 606 -130.151 1.931464815 195.71 581 -129.659 0.986 200.27 535 -123.819 0.855 202.55 515 -121.492 0.01 205.97 486 -119.092 1.085 209.39 461 -125.863 0.061 212.81 437 -124.256 0.393 216.23 416 -126.791 0.579 220.79 389 -123.126 0.707 223.07 377 -124.572 0.444 226.49 358 -126.791 1.464 227.63 352 -122.777 1.113 229.91 340 -129.195 0.319 236.75 302 -119.620 3.264 250.43 211 -112.134 0.997