10Be和26Ai揭示的合黎山西南部侵蚀速率初步研究

地表侵蚀速率是衡量地貌演化的一个重要因子。本研究利用原地宇宙成因核素 10Be 和 26Al 对合黎山西南部地表岩石侵蚀速率进行了首次测定。结果显示：约 30 ka 以来，合黎山西南部的地表岩石侵速率约为 24 mm∙ka-1。这一结果与已见报道的其他基岩侵蚀速率值一致。这一结果与 Small et al 获得的非干旱地区的基岩侵蚀速率也基本一致，但是显著高于干旱的南极地区和半干旱的澳大利亚。10Be 和26Al 获得的侵蚀速率的良好一致性表明本研究中所用侵蚀模式的有效性。所得的侵蚀速率小于 Palumbo et al 测定的合黎山平均流域侵蚀速率（99 mm∙ka-1），原因解释尚待更多地点和样品的研究。<br style="line-height: normal; text-align: -webkit-auto; text-size-adjust: auto;" /

Extensive glacial advances during the Last Glacial Maximum near theeastern Himalayan syntaxis

Climatically, the eastern Himalaya are mainly controlled by the Indian Summer Monsoon (ISM) and important region for understanding the relationship between ISM and glacial change. This region is therefore useful for studies of the relation between glacial changes and ISM. Using a geomorpho-stratigraphic method combined with GIS, we investigated and mapped the outmost lateral-frontal moraine of the most extensive glaciations that occurred in the Basongcuo (BSC) catchment, near the eastern Himalayan syntaxis. Using optically stimulated luminescence (OSL) and &sup1;⁰Be surface exposure dating technique, we dated five boulders and 23 sediment samples. The resultant OSL and &sup1;⁰Be ages show that the region&#39;s glaciers were at their most extensive positions between &sim;16 and 31 ka. Glacial coverage was 507.5 km&sup2;, 9.9 times greater than it is today (51.5 km&sup2;), with an equilibrium line altitude (ELA) depression of &sim;690 m. The rapidity with which the Last Glacial Maximum (LGM) glacial advance and retreat occurred suggests that temperature was the dominant control on glacial change

Long-lived radionuclides as chronometers and tracers of environmentalprocesses at the Xi'an Accelerator Mass Spectrometry Center

Long-lived radionuclides with half-lives ranging from 103 to 108 years have wide applications in geochronology and environmental tracer studies. A wide range of climatic, geologic, and environmental records preserved in diverse natural archives can be characterized by measuring their concentrations, using accelerator mass spectrometry (AMS). The purpose of this paper is to highlight some representative works on 14C, 10Be, 26Al and 129I in these two aspects at the Xi&#39;an AMS Center in the past ten years, since a dedicated AMS facility was established. The improvement of the sample preparation procedures, the development of the new mathematical analysis method and related applications are summarized