A late-Holocene (<2600 BP) glacial advance in the south-central Andes (29°S), northern Chile
A late-Holocene (<2600 BP) glacial advance in the south-central Andes (29°S), northern Chile
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智利北部安第斯山脉中南部（南纬29°）的全新世晚期（<2600 BP）冰川推进
DOI：
10.1191/095968398677627864
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
H. Veit
中科院分区：
文献类型：
--
作者：
M. Grosjean;M. Geyh;B. Messerli;H. Schreier;H. Veit
冰碛上土壤的放射性碳年代测定和相对年龄提供了证据，证明在南纬29°的干旱安第斯山脉西部，全新世晚期（<2600 BP）冰川有大量的再流入。智利北方恩西耶罗山谷的冰川达到了晚更新世冰川面积的60%。在这一推进过程中，平衡线高度ELA保持在4250和4500米之间，高于夏季自由大气的现代0°C等温线。有人建议，在极端干旱的安第斯山脉的高海拔地区的特定气候，有效水分的大幅增加足以解释这一进步，而没有显着的温度下降是必要的。这与该地区晚全新世的气候历史相比较有利，当时湖泊水位较高，有效湿度大于今天的3000和1800 BP之间。从区域古资料判断，我们认为，这晚全新世潮湿的拼写是最有可能与来自太平洋的西风水汽源增加。
Radiocarbon dates and relative ages of soils on moraines provide evidence of a substantial late-Holocene (<2600 BP) readvance of glaciers in the western part of the arid Andes at 29°S. The glacier in the Encierro valley, northern Chile, reached about 60% of its late-Pleistocene extent. The equilibrium line altitude ELA during this advance remained between 4250 and 4500 m which is above the modern 0°C isotherm of the free atmosphere during summer. It is suggested that, given the specific climate at high elevations in the extremely arid Andes, a substantial increase in effective moisture is sufficient to explain this advance, whereas no significant temperature depression was needed. This compares favourably with the regional late-Holocene climatic history, when lake levels were higher and effective moisture greater than today between 3000 and 1800 BP. Judging from regional palaeodata, we suggest that this late-Holocene humid spell was most likely related to increased Westerly moisture sources from the Pacific.