A mid-Holocene tufa section at 3,815 m altitude in the Qilian Mountains at the northeastern margin of the Tibetan Plateau was tested as a possibly important new climate archive. The tufa carbonate displays a distinct ...A mid-Holocene tufa section at 3,815 m altitude in the Qilian Mountains at the northeastern margin of the Tibetan Plateau was tested as a possibly important new climate archive. The tufa carbonate displays a distinct alternation of white and dark layers most probably representing annually deposited sparry and microgranular calcite which is formed during the warm and relatively wet summer and the drier and cooler spring and autumn season with an interruption of tufa formation during the freezing period. The δ^18O record of the tufa site comprises probably 357 years of annually deposited car-bonate-about 4, 000 years bejCore present, which indicates the prevalence of wetter climatic con- ditions in comparison to the present-day situation. This inference is confirmed by palynological data and lake-level reconstructions from a number of sites in the northern foreland of the Qilian Mountains, highlighting the large potential of longer tufa sequences for high-resolution palaeoclimate studies in the future.展开更多
文摘A mid-Holocene tufa section at 3,815 m altitude in the Qilian Mountains at the northeastern margin of the Tibetan Plateau was tested as a possibly important new climate archive. The tufa carbonate displays a distinct alternation of white and dark layers most probably representing annually deposited sparry and microgranular calcite which is formed during the warm and relatively wet summer and the drier and cooler spring and autumn season with an interruption of tufa formation during the freezing period. The δ^18O record of the tufa site comprises probably 357 years of annually deposited car-bonate-about 4, 000 years bejCore present, which indicates the prevalence of wetter climatic con- ditions in comparison to the present-day situation. This inference is confirmed by palynological data and lake-level reconstructions from a number of sites in the northern foreland of the Qilian Mountains, highlighting the large potential of longer tufa sequences for high-resolution palaeoclimate studies in the future.
