Last Glacial Maximum equilibrium-line altitudes and paleoclimate, northern Uinta Mountains, Utah, U.S.A.
Last Glacial Maximum equilibrium-line altitudes and paleoclimate, northern Uinta Mountains, Utah, U.S.A.
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DOI：
10.3189/172756502781831331
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发表时间：
2002
影响因子：
3.4
通讯作者：
J. Munroe;D. Mickelson
中科院分区：
文献类型：
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作者：
J. Munroe;D. Mickelson
对美国犹他州尤因塔山北方19个前山谷冰川的末次盛冰期（LGM）范围进行了重建。用四种方法（堆积面积比、坡脚-端壁高度比、侧碛和冰斗底）计算的平均平衡线高度（ELA）范围为3050 - 3300 m a.s. l。现代ELA的夏季平均气温（Ts）为8.7° C至11.2°C，而现代冬季降水量（P）为354至590 mm雪水当量（SWE）。根据整个范围内平均ELA的海拔差异，LGM P值必须在940至3040 mm SWE之间，假设现代夏季递减率在LGM期间相同。这些降水值需要5.5°C的Ts下降才能在现代ELA值范围内绘图。该山脉西端重建的P增加量是现代增加量的10倍，反映了多雨的邦纳维尔湖的影响。假设ELA下降（ΔELA）是由P的增加和均匀的5.5°C Ts下降引起的，则区域LGM ΔELA约为900 m。
Abstract Nineteen former valley glaciers were reconstructed for their Last Glacial Maximum (LGM) extents in the northern Uinta Mountains, Utah, U.S.A. Mean equilibrium-line altitudes (ELAs) calculated by four methods (accumulation–area ratio, toe–headwall altitude ratio, lateral moraines and cirque floors) range from 3050 to 3300 m a.s.l. Modern mean summer temperatures (Ts) at the ELAs range from 8.7° to 11.2°C, while modern winter precipitation (P) ranges from 354 to 590 mm snow water equivalent (SWE). Based on the difference in elevation of mean ELAs across the range, LGM P values must have ranged from 940 to 3040 mm SWE, assuming the modern summer lapse rate was the same during the LGM. A Ts depression of 5.5°C is required for these precipitation values to plot in the range of modern ELA values. The reconstructed increase in P at the western end of the range is 10 times the modern increase, reflecting the influence of pluvial Lake Bonneville. Assuming ELA depression (ΔELA) resulted from this P increase and a uniform 5.5°C T s decrease, the regional LGM ΔELA was approximately 900 m.