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本次研究得出了2.5 Ma BP以来洛川剖面黄土-古土壤序列的酸不溶物~(87)Sr/~(86)Sr、Rb/Sr、磁化率和沉积速率的变化曲线。黄土和古土壤酸不溶物~(87)Sr/~(86)Sr、Rb/Sr和磁化率的变化具有类似的阶段性和周期性,这与晚新生代以来古气候的主要变化以及行星轨道参数相一致。研究证明,黄土和古土壤酸不溶物~(87)Sr/~(86)Sr值是化学风化强度的替代指标,沉积速率是物理风化强度的替代指标。自2.5 Ma BP以来在喜马拉雅山的北面风化强度的变化分为两个阶段,其界限在约1.2 Ma BP。自2.5 Ma BP以来化学风化强度在总体上呈下降趋势,而物理风化强度呈上升趋势。物理风化强度总的增长可能是导致海水~(87)Sr/~(86)Sr迅速上升的主要原因。
The results of this study show that the change of ~ (87) Sr / ~ (86) Sr, Rb / Sr, magnetic susceptibility and deposition rate of the acid insoluble matter in the loess-paleosol sequence of the Luochuan section of the Luochuan section since 2.5 Ma BP. The changes of ~ (87) Sr / ~ (86) Sr, Rb / Sr and magnetic susceptibility in loess and paleosol are similar in stage and periodicity, which are related to the major changes of palaeoclimate since the Late Cenozoic, The parameters are consistent. The results show that the ~ (87) Sr / ~ (86) Sr value of loess and paleosol is an alternative indicator of chemical weathering intensity, and the sedimentation rate is an alternative index of physical weathering intensity. The change in weathered intensity north of the Himalayas since 2.5 Ma BP is divided into two phases with a limit of about 1.2 Ma BP. The chemical weathering intensity has generally declined since 2.5 Ma BP and the physical weathering intensity has been on the rise. The overall increase of physical weathering intensity may be the main reason for the rapid increase of ~ (87) Sr / ~ (86) Sr in seawater.