Current Browsing: Palaeoenvironment


Fossil of zooplankton remains, pigment and nutrients in Dagze Co, central Tibet Plateau (1440-2002 A.D.)

Paleoecological and paleolimnological studies can provide a long-term perspective on changes in environmental and ecosystem processes. The sediments documented both direct and indirect impacts of climate change and human activities on aquatic ecosystems. The fossils of zooplankton remain and pigments in lake sediments can reflect community structure changes of primary producers and primary consumers. The authors reconstructed the zooplankton and algal community changes during the past 600 years using carapaces of A. tibetiana and resting eggs of D. tibetana and pigments from the sediments of Dagze Co, in the central Tibet Plateau. Using total nitrogen and total phosphorus reconstructed the nutrient changes. These results suggest that algal community structure and changes in production can be attributed to alterations in the zooplankton community, with important implications for Tibetan aquatic ecosystems.

2022-04-19

Carbon and oxygen data of tree rings in the Qilian Mountains of China in the East Asian monsoon region

This data set consists of tree ring carbon and oxygen data in East Asian monsoon region and Qilian Mountain region of China. Tree rings in Qilian mountain area include 4 tree cores, the tree species is Sabina przewalskii, and the measured isotopic data is 921. Cellulose was extracted from tree ring logs by chemical treatment, and the obtained cellulose samples were wrapped in a silver cup. The isotopic ratio was measured by Delta V advantage stable isotope mass spectrometer, and the analysis error was less than 0.21 ‰. The experimental analysis was completed in the laboratory of soil structure and minerals, Institute of Geology and Geophysics, Chinese Academy of Sciences. This data has certain significance for the study of paleoclimate in East Asian monsoon region.

2022-04-19

Tree ring width data of Qilian mountains in the East Asian Monsoon region

This data set is composed of tree ring width data of Qilian Mountain region of China in East Asian monsoon region . The tree rings in Qilian mountain contain 52 tree cores, which have 17081 values, the measurement accuracy is 0.01mm, and the tree species is Qilian juniper. The tree ring width was measured by lintab 6 tree ring analyzer, and the cross dating is checked by coffcha program to guarantee that the accuracy of the dating. The experiment analysis was performed in the laboratory of soil structure and minerals, Institute of Geology and Geophysics, Chinese Academy of Sciences. This data has certain significance for the study of paleoclimate in the edge of East Asian monsoon region .

2022-04-18

Tree age data sampled from different glacier moraines in the central Himalayas

Data set contains tree age of trees growing at different glacier moraines in the central Himalayas. The data were obtained using tree ring samples. Cores samples were collected (almost near to the ground level to estimate the minimum age of the related moraine) using an increment borer. Samples were processed by using standard dendrochronological techniques.

2022-04-15

2022-04-15

Spring hydroclimate reconstruction on the south-central Tibetan Plateau

Data content: Standard ring-width chronology derived from Wilson juniper shrub around the northern shore of the Nam Co Lake; May-June SZI (Standardized Moisture Anomaly Index) drought reconstruction for the Nam Co region. Time span: 1605 to 2010. Temporal resolution: Yearly. Application and prospects: Hydroclimate study on the south-central Tibetan Plateau.

2022-04-15

Fossil of zooplankton remains, pigment and nutrients in Dagze Co, central Tibet Plateau (1440-2002 A.D.)

Paleoecological and paleolimnological studies can provide a long-term perspective on changes in environmental and ecosystem processes. The sediments documented both direct and indirect impacts of climate change and human activities on aquatic ecosystems. The fossils of zooplankton remain and pigments in lake sediments can reflect community structure changes of primary producers and primary consumers. The authors reconstructed the zooplankton and algal community changes during the past 600 years using carapaces of A. tibetiana and resting eggs of D. tibetana and pigments from the sediments of Dagze Co, in the central Tibet Plateau. Using total nitrogen and total phosphorus reconstructed the nutrient changes. These results suggest that algal community structure and changes in production can be attributed to alterations in the zooplankton community, with important implications for Tibetan aquatic ecosystems.

2020-10-25

Age data of the deep sediment core in the midstream of the Heihe River

This data set contains a deep drilling paleomagnetic age data near the open sea in the middle reaches of Heihe River. The borehole is located at 99.432 E and 39.463 n with a depth of 550m. The samples of paleomagnetic age were taken at the interval of 10-50 cm. The paleomagnetic test was carried out in the Key Laboratory of Western Ministry of environmental education of Lanzhou University. The primary remanence of the samples was obtained by alternating demagnetization and thermal demagnetization, and the whole formation magnetic formation was obtained by using the primary remanence direction of each sample, and then the sedimentary age of the strata was obtained by comparing with the standard polarity column. The results show that the bottom boundary of the borehole is about 7 Ma and the top boundary is 0 ma.

2020-07-30

Palynological data of vegetation evolution since the formation of Heihe River

Since the formation of Heihe River, sporopollen data samples have been collected from the drilling strata of Da'ao well in the middle reaches of Heihe River. Drilling location: 39.491 n, 99.605 E. The drilling depth is 140 meters. 128 samples of sporopollen are collected from top to bottom. At present, there are 19 data of sporopollen results, which are distributed in each sedimentary facies from top to bottom. The sporopollen samples were removed from carbonate, organic matter, silicate and other impurities in the laboratory, and the species and data of sporopollen were identified under the microscope. Sporopollen results mainly include the percentage content and number of trees, shrubs, herbs, aquatic, ferns and other families and genera.

2020-07-28

Ages of geomorphic surfaces along the Heihe River (late pleistocene)

Based on the study of the terrace formation age in the upper reaches of heihe river, photoluminescence samples were collected from the sediments of grade 6 river terrace near the upper reaches of qilian river.The quartz particles (38-63 microns) in the sample were isolated in the laboratory, the equivalent dose and dose rate in the quartz particles were measured, and the photoluminescence age of the sample was finally obtained.The obtained ages range from 5ka to 82ka, corresponding to the years of cutting down the terraces of all levels.

2020-07-28