Understanding the modern relationships between pollen and vegetation, climate, and human land-use completely, is essential for quantitative reconstructions of past vegetation, climate and human impacts. supported by the Second Tibetan Plateau Scientific Expedition Program, we have collected more than 700 surface-soil samples together with detail vegetation survey. Hitherto, pollen analysis of 318 samples have been completed, and the submitted modern pollen dataset includes the pollen percentages of 24 common taxa, the sampling sites of the dataset cover the all vegetation types on the east and central Tibetan Plateau. The dataset can be utilized in establishment for pollen-climate, pollen-vegetation calibration-sets.
CAO Xianyong
This dataset is the biome change data of the Tibetan Plateau since the last glacial maximum which was reconstructed by using a new method. Firstly, a random forest algorithm was applied to establish a pollen-biome classification model for reconstructing past vegetation changes of the Tibetan Plateau, and 1802 modern pollen assemblages from 17 vegetation zones in and around the Tibetan Plateau were used as the training set for the model development. The random forest model showed a reliable performance (accuracy > 76%) in predicting modern biomes from modern pollen assemblages based on a comparison with the observed biomes. Moreover, the random forest model had a significantly higher accuracy than the traditional biomization method. Then, the newly established random forest model is applied to the paleovegetation reconstruction of 51 fossil pollen sequences of the Tibetan Plateau. New age-depth models were developed for these fossil pollen records using the Bayesian method, and all fossil pollen records were linearly interpolated to 500-year time slices. Finally, the spatiotemporal changes of biomes on the Tibetan plateau over the past 22,000 years at an interval of 500 years were reconstructed by using the random forest model. This dataset can provide evidence for understanding the past variation of alpine vegetation and its mechanism; provide the basis for studying the impact of past climate change on vegetation on the Tibetan Plateau; and provide boundary conditions for climate simulation.
QIN Feng , ZHAO Yan, CAO Xianyong
The present data are chronological and palynological data from the Luanhaizi Lake core in the Menyuan Basin, northeastern Tibetan Plateau. We used the AMS14C method to test nine dated samples from the LHZ18 core. Bulk samples were collected from plant remains and organic-rich horizons from the core LHZ18 for accelerator mass spectrometry (AMS)14C dating. Samples were measured at Beta Labs in the USA and Lanzhou University.Pollen analysis was completed at the Key Laboratory of Western China’s Environment Systems,Ministry of Education, Lanzhou University, with 140 stratigraphic pollen samples and 10 topsoil pollen samples. Spore pollen identification statistics were carried out under a light microscope.The pollen results mainly include the number of grains of trees, shrubs, herbs and aquatic plants.
HUANG Xiaozhong, ZHANG Jun, WANG Tao
A 170-cm-long sediment core was extracted from Lake Xingxinghai at a water depth of 9 m (34°50.44′N, 98°06.34′E) in January 2010 using Austria’s UWITEC platform coring equipment. Both the 210Pb/137Cs and AMS 14C (11 dating data) approaches were applicated into the age-depth model establishment using Bayesian age–depth modelling by the “Bacon” software, and the age-depth model indicates the core covers the past 7400 years. The core was sliced at 0.5-cm interval upper 3 cm and 1-cm interval for other part, finally we got 173 samples totally. Pollen grains were extracted using a procedure including the treatments with 10 % HCl, 10 % NaOH and 40 % HF, followed by a 7-μm mesh sieving and acetolysis treatment (9:1 mixture of acetic anhydride and sulfuric acid). Pollen grains were identified and counted under optical microscope, and at least 300 terrestrial pollen grains were counted for each sample. The mean temporal resolution of pollen spectra is ca. 40 year/sample. The pollen spectra include forty-eight pollen taxa, are dominated by herbaceous taxa (range: 88.5~98.9%; mean: 93.4%), such as Artemisia (up to 54.4%), Cyperaceae (up to 50.1%), Poaceae (up to 48.8%), Chenopodiaceae (up to 17.9%) and Asteraceae (up to 8.5%). Abundance of arboreal pollen is less than 5% through out the core, mainly comprised of Pinus (maximum: 4.9%; mean:1.2%) and Betula (maximum: 3.0%; mean: 0.7%). The pollen dataset includes pollen percentages for the 43 terrestrial pollen taxa together with their depths and ages, and the dataset is valuable to employed in past vegetation and climate reconstructions.
TIAN Fang, CAO Xianyong
We have completed the pollen analyses of 252 sedimentary samples from Dahonggou section in Qaidam Basin covering the Cenozoic. Palynomorph extraction followed the routine process with HCl and HF treatments during the extraction. Airborne pollen-charcoal traps and surface-sediment samples from soils were collected to evaluate the relationship between pollen-charcoal contents and vegetation structure, and effect of sedimentary environment conditions on the pollen dispersal and deposition. Combined with pollen-charcoal data from other sections, we are going to establish the fire history spanning the last 30 Ma years, and to discuss the responds and feedbacks of the vegetation and fire to the climate changes. Our work is beneficial to the knowledge of the processes of aridification in Inner Asia and its mechanism. The submitted pollen data set is according to the proposal, and in order to guarantee data accuracy, 20% of the data have been examined in our lab by random sampling method. Data collection and analysis are continued, we hope our work can contribute more to the project in the next few years.
MIAO Yunfa
By archaeological investigation and excavation in Tibetan Plateau and Hexi corridor, we discovered more than 40 Neolithic and Bronze Age sites, including Zongri, Sanjiaocheng, Huoshiliang, Ganggangwa, Yigediwonan, Shaguoliang, Guandi, Maolinshan, Dongjicuona, Nuomuhong, Qugong, Liding and so on. In this dataset, there are some basic informations about these sites, such as location, longitude, latitude, altitude, material culture and so on. On this Basis, we identified animal remains, plant fossil, selected some samples for radiocarbon dating, optically stimulated luminescence dating, stable carbon, nitrogen isotopes, polle, fungal sporen and environmental proxies. This dataset provide important basic data for understanding when and how prehistoric human lived in the Tibetan Plateau during the Neolithic and Bronze Age.
YANG Xiaoyan, Lü Hongliang, LIU Xiangjun, HOU Guangliang
The source of the data is paper: Zhang, J.F., Xu, B.Q., Turner, F., Zhou, L.P., Gao, P., Lü, X.M., & Nesje, A. (2017). Long-term glacier melt fluctuations over the past 2500 yr in monsoonal high asia revealed by radiocarbon-dated lacustrine pollen concentrates. Geology, 45(4), 359-362. In this paper, the researcher of Institute of Tibetan Plateau Research, Chinese Academy of Sciences and CAS Center for Excellence in Tibetan Plateau Earth Sciences, Baiqing Xu, with his postdoctoral fellow, Jifeng Zhang, and collaborators from Peking University and other institutions, propose that the OPE (“old pollen effect”, the offset between the calibrated 14C ages of pollen in lake sediments and the sediment depositional age) as a new indicator of glacier melt intensity and fluctuations by measuring the radiocarbon ages of the sediments of the proglacial lake of Qiangyong Glacier on the southern Tibetan Plateau with multi-methods (bulk organic matter, pollen concentrates and plant residues). This research suggests that hemispheric-scale temperature variations and mid-latitude Westerlies may be the main controllers of the late Holocene glacier variability in monsoonal High Asia. It also shows that the 20th-century glacier melt intensity exceeded that of two historical warm epochs (the Medieval Warm Period, and the Iron/Roman Age Optimum) and is unprecedented at least for the past 2.5 k.y. This data is provided by the author of the paper, it contains long-term glacier melt fluctuations of Qiangyong Glacier over the past 2500 yr reconstructed by the OPE. A 3.06-m-long core (QYL09-4) and a 1.06-m-long parallel gravity core (QY-3) were retrieved by the researchers from the depositional center of Qiangyong Co. Using a new composite extraction procedure, they obtained relatively pure pollen concentrates and plant residue concentrates (PRC; >125 μm) from the finely laminated sediments. Bulk organic matter and the PRC and pollen fractions were used for 14C dating independently. All 14C ages were calibrated with IntCal13 (Reimer et al., 2013). The age-depth model is based on 210Pb and 137Cs ages and five 14C ages of PRC. Only the youngest PRC ages were used for the age-depth model, whereas older ages that produce a stratigraphic reversal and are apparently influenced by redeposited or aquatic plant material were rejected. The deposition model was constructed using the P_Sequence algorithm in Oxcal 4.2 (Bronk Ramsey, 2008). For the calculation of the offset between the calibrated pollen 14C ages and the sediment depositional age, 2σ intervals for interpolated ages according to the deposition model were subtracted from calibrated pollen ages (2σ span), resulting in the age offset between pollen and estimated sediment ages (ΔAgepollen). This data is radiocarbon ages and the calculated ΔAgepollen of core QYL09-4 from a proglacial lake of Qiangyong Glacier. The data contains fields as follows: Lab No. Dating Material Depth (cm) 14C age (yr BP) ∆Agepollen (≥95.4 % yrs) Sediment Age (CE) See attachments for data details: ZhangJF et al. 2017 GEOLOGY_Long-term glacier melt fluctuations over the past 2500 yr on the Tibetan Plateau.pdf.
ZHANG Jifeng
This dataset contains data on the lake core sporopollen spectrum and temperature/precipitation reconstruction sequence of Yamdrog Yumtso Lake in the southern Tibetan Plateau. It is used to study the environmental changes in the Yamdrog Yumtso region by 20 ka. It is obtained by the sporopollen analysis method. This data set is obtained by laboratory measurement and calculation. The samples and data are collected and identified in strict accordance with relevant operating procedures at all stages. There are three subtables in this dataset. The first two tables comprise the following analysis data of TC1 pore sporopollen samples. Field 1: Sample Number Field 2: Sample Depth Unit: cm Field 3: Sample Age Unit: aBP Field 4: Total sporopollen concentration Units: granules/gram Field 5: Total Pollen Granules Unit: Number of grains Field 6: Total number of indicative pollen Unit: Number of grains Field 7: Identification of indicative pollen number Unit: Number of grains Field 8: Sample Weight Unit: Grams Field 9: Concentration Coefficient Units: granules / gram Field 1: Sample Number Field 2: Plant species Field 3: Pollen content Unit: % The third subtable is the reconstructed temperature precipitation and has 6 fields. Field 1: Sample Code Field 2: Sample Name Field 3: Depth Unit: cm Field 4: Age Unit: aBP Field 5: Average annual temperature Unit: 0.1 °C Field 6: Annual precipitation Unit: 0.1 mm The rock core was collected from the Yamdrog Yumtso Basin in the southern part of the Tibetan Plateau. The approximate sampling location is 90°27′E，28°56′N, and the altitude there is 4425 m.
WANG Junbo, LV Houyuan
The project studying the evolution pattern and development trend of the arid environment in western China was a major research component of the project Environmental and Ecological Science for West China, which was funded by the National Natural Science Foundation of China. The leading executive of the project was Academician Zhisheng An from the Institute of Earth Environment of the Chinese Academy of Sciences. The project ran from January 2002 to December 2004. The data collected by the project include the following: 1. History and variability data for arid regions in western China: 1) Chinese Loess Plateau mass accumulation rate data (3600-0 kyr BP): Fields include age and mass accumulation rate (MAR) (txt file). 2) Chinese Loess Plateau grain size and magnetic susceptibility data (3600-0 kyr BP): Fields include age, stacked mean grain size, and stacked magnetic susceptibility (txt file). 2. Sporopollen content data of different loess strata since 12 kyr BP in the Yaozhou District of Shanxi Province (excel table): The distributions of 27 species of sporopollen (0-397 cm) from 67 different layers of loess samples are included. 3. 10Be record data (table) 10Be concentration, magnetic susceptibility and bulk density data of loess with different thicknesses (79.67- 0.09 kyr BP). 4. Simulation data on the modulation of the East Asian monsoon resulting from orbital variability driven by the uplift of the Tibetan Plateau: ah0-sum.nc nc file, hh0-sum.nc nc file, jfh0-sum.nc nc file, kdh0-sum.nc nc file, lfh0-sum.nc nc file, mask.nc nc file, phis.nc nc file.
AN Zhisheng
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