# Lake Ximencuo, Tibet 1000 Year Multiproxy Sediment Data #----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # NOTE: Please cite original reference when using these data, # plus the Online Resource and date accessed. # # Online_Resource: http://hurricane.ncdc.noaa.gov/pls/paleox/f?p=519:1:::::P1_STUDY_ID:14388 # # Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/asia/tibet/ximencuo2013xmc6.txt # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Paleolimnology #-------------------- # Contribution_Date # Date: 2013-05-12 #-------------------- # Title # Study_Name: Lake Ximencuo, Tibet 1000 Year Multiproxy Sediment Data #-------------------- # Investigators # Investigators: Pu, Y.; Nace, T.; Meyers, P.A.; Zhang, H.; Wang, Y.; Zhang, C.L.; Shao, X. #-------------------- # Description_and_Notes # Description: Total organic carbon (Corg) and nitrogen (Ntot) concentrations and isotope # compositions and n-alkane and n-alkan-ol molecular biomarker compositions # were measured in two parallel sediment cores from Lake Ximencuo, a typical # glacial lake on the eastern Qinghai-Tibetan Plateau (QTP), to reconstruct # local climatic variations during the past 1000 yr. # XimenCuo core XMC-5 data are plotted in Fig.3 and Fig.9 # XimenCuo core XMC-6 data are plotted in Fig.7 and Fig.9 # #-------------------- # Publication # Authors: Yang Pu, Trevor Nace, Philip A. Meyers, Hucai Zhang, Yongli Wang, Chuanlun L. Zhang, Xiaohua Shao # Published_Date_or_Year: 2013-06-01 # Published_Title: Paleoclimate changes of the last 1000 yr on the eastern Qinghai-Tibetan Plateau recorded by elemental, isotopic, and molecular organic matter proxies in sediment from glacial Lake Ximencuo # Journal_Name: Palaeogeography, Palaeoclimatology, Palaeoecology # Volume: 379-380 # Edition: # Issue: # Pages: 39-53 # DOI: 10.1016/j.palaeo.2013.03.023 # Abstract: Total organic carbon (Corg) and nitrogen (Ntot) concentrations and isotope compositions and n-alkane and n-alkan-ol molecular biomarker compositions were measured in two parallel sediment cores from Lake Ximencuo, a typical glacial lake on the eastern Qinghai-Tibetan Plateau (QTP), to reconstruct local climatic variations during the past 1000 yr. Concentrations of Corg and Ntot vary similarly with changes in precipitation recorded by tree rings in Dulan, northeastern QTP, indicating their close relation to precipitation. Carbon Preference Index (CPI) values of C22-C33n-alkanes and C22-C28n-alkan-1-ols and Average Chain Length (ACL) values of C27-C33n-alkanes generally negatively correlate with d13Corg and d15Ntot and also vary comparably with the oxygen isotope temperature record from the Dunde ice core, northeastern QTP. These patterns indicate that high CPI values and negative shifts of the d13Corg and d15Ntot correspond to warmer conditions that favor the growth of vascular land plants and that lower values and positive shifts correspond to cooler conditions in the Lake Ximencuo locality. This observation contradicts previous interpretations from peat and modern soil studies that conclude that the CPI indices were controlled by microbial degradation under different climate conditions. Here we propose that the changes of organic matter sources under different climate regimes, combined with physiological adjustments of vascular plants to different air temperatures, might yield different CPI responses to climate changes in glacial plateau lakes. Air temperature and precipitation increases and decreases reconstructed in this 1000-yr study were generally independent of each other, but they both occurred at centennial or multi-centennial scales. The interaction between subtropical (Asian Monsoon) and mid-latitude (Westerly) atmospheric circulation systems probably dominated the local precipitation variations in the Lake Ximencuo catchment, whereas solar insolation, volcanism and greenhouse gas variations were likely responsible for the air temperature changes that are recorded in the lake sediments and that are consistent with regional temperature variations in the eastern QTP. #------------------ # Funding_Agency # Funding_Agency_Name: Major State Basic Research Development Program of China # Grant: 2012CB214701 #------------------ # Funding_Agency # Funding_Agency_Name: Chinese Academy of Sciences Key Project # Grant: XDB03020405 #------------------ # Funding_Agency # Funding_Agency_Name: National Natural Science Foundation of China # Grant: 40871096 #------------------ # Site_Information # Site_Name: Lake Ximencuo # Location: Asia>Eastern Asia>China # Country: China # Northernmost_Latitude: 33.378 # Southernmost_Latitude: 33.378 # Easternmost_Longitude: 101.106 # Westernmost_Longitude: 101.106 # Elevation: 4020 m #------------------ # Data_Collection # Collection_Name: XMC-6 # Earliest_Year: 1154 # Most_Recent_Year: 1989 # Time_Unit: AD # Core_Length: 0.44 m # Notes: #------------------ # Chronology: # # Table 2 # Summary of the 210Pbtot, 210Pbexc and 137Cs radiochronological data. # # Depth(cm) 210Pbtot(dpm/g)Activity Err(+/-) 210Pbexc(dpm/g)Activity Err(+/-) 137Cs(dpm/g)Activity Err(+/-) # 0-1 75.59 8.73 70.94 8.74 6.31 0.41 # 1-2 44.52 5.56 40.07 5.58 8.28 0.34 # 2-3 33.58 4.50 28.81 4.54 4.48 0.27 # 3-4 13.09 4.22 7.76 4.22 2.41 0.31 # 4-5 10.83 3.50 5.62 3.54 0.93 0.24 # 5-6 8.25 2.14 4.19 2.18 0.45 0.14 # 6-7 3.78 1.76 0.06 1.89 0.05 0.12 # 7-8 2.78 1.38 -1.48 1.39 0.00 0.00 # 8-9 5.67 2.35 0.47 2.51 0.00 0.15 # # #---------------- # Variables # # Data variables follow (have no #) # 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_top Depth top of sample interval, , , cm, , , , ,N ## depth_bottom Depth bottom of sample interval, , , cm, , , , ,N ## depth_cm depth, , , cm, , , middle of sample, ,N ## age_AD age, , , AD, , , , ,N ## CPI21-33ALK Carbon Preference Index of C21-C33 n-alkanes, , , , , , , ,N ## ACL27-33ALK Average Chain Length (ACL) of C27–C33 n-alkanes, , , , , , , ,N ## CPI22-28ACH Carbon Preference Index of C22–C28 n-alkan-ols, , , , , , , ,N ## ACL22-28ACH Average Chain Length (ACL) of C22–C28 n-alkan-ols, , , , , , , ,N # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # XimenCuo core XMC-6 data are plotted in Fig.7 and Fig.9 depth_top depth_bottom depth_cm age_AD CPI21-33ALK ACL27-33ALK CPI22-28ACH ACL22-28ACH 0 2 1 1989.12 5.23 29.73 7.03 25.13 2 4 3 1949.36 5.47 29.67 7.89 25.25 4 6 5 1909.60 7.45 29.82 10.27 24.90 6 8 7 1869.83 5.52 29.77 6.24 25.19 8 10 9 1830.07 5.72 29.80 6.52 25.30 10 12 11 1790.31 5.70 29.72 5.69 25.40 12 14 13 1750.55 5.98 29.73 5.68 25.09 14 16 15 1710.79 5.52 29.68 5.84 25.02 16 18 17 1671.03 5.24 29.76 6.85 25.26 18 20 19 1631.27 5.38 29.56 4.73 24.66 20 22 21 1591.50 5.31 29.57 5.99 24.83 22 24 23 1551.74 5.09 29.40 4.90 24.68 24 26 25 1511.98 8.03 29.93 9.07 25.06 26 28 27 1472.22 6.11 29.70 7.06 24.99 28 30 29 1432.46 7.48 29.77 6.51 24.68 30 32 31 1392.70 6.30 29.78 6.72 24.75 32 34 33 1352.94 7.03 29.91 5.97 25.05 34 36 35 1313.17 8.03 29.86 6.38 25.00 36 38 37 1273.41 6.09 29.70 5.64 24.88 38 40 39 1233.65 7.04 29.75 8.00 25.03 40 42 41 1193.89 5.34 29.60 6.31 24.97 42 44 43 1154.13 6.34 29.81 6.64 24.90