Holocene glacier variation and their mechanism in Patagonia, South America

1998年，在北巴塔哥尼亚冰原的野外工作中获得了以下结果：Soler冰川和Soler河流域Nef冰川的全新世冰川变化研究表明，终端冰碛的分布和位置表明新仙女木期（约10,500 BP）和新冰期（约2000 BP）的存在；然而，这些假设还有待碳14和宇宙射线定年法的证实。在Soler冰川消融区测量了冰川流量、地表剖面和应变率，并进行了水文和气象观测。研究结果包括，基底滑动量占冰川流动的很大一部分。地表剖面测量结果显示，1986年以来地表高程降低了42±5 m，年平均变薄率为3.2±5 m。1998年对北巴塔哥尼亚冰原出口冰川口进行的航空摄影调查显示，自1995年以来，冰川发生了变化。除了一个（圣拉斐尔冰川）外，所有的出水口冰川在此期间都退缩了。1999年的航空摄影调查揭示了一个非常有趣的现象。圣拉斐尔冰川自1993年以来一直在前进，但在1998年至1999年间被发现已经退缩。根据这一观察结果，我们假设圣拉斐尔冰川的异常移动可能不像以前假设的那样是由于20世纪70年代初的降雨增加，而可能是由于峡湾地形和冰川动力学。1999年11 - 12月，在南巴塔哥尼亚冰原的Tyndall冰川堆积区完成了冰钻，获得了46米长的冰芯样本，并进行了现场观测。对冰芯的详细化学分析将在不久的将来完成。在Perito Moreno冰川，用摄影测量法测量了产犊活动，并通过记录产犊引起的潮汐波来估计产犊量。对湖泊进行了水深测量，揭示了冰川前缘附近的深度可达80米。测量了乌普萨拉冰川流入的Brazo Upsala的深度，最大深度接近700 m。水深资料对分析冰裂活动、冰川动力和冰川变化之间的关系具有重要意义。少

In 1998, the following results were obtained from field work in the Northern Patagonia Icefield. As for the study of the Holocene glacier variation of Soler Glacier, and Nef glacier in the valley of Soler River, the distribution and location of terminal moraines suggest the existence of the Younger Dryas advance (ca. 10,500 BP) and the Neoglaciation II (ca. 2000 BP) ; however, these suppositions awaits for confirmation by carbon 14 and cosmic ray datings. At Soler Glacier, glacier flow, the surface profile, strain rates were measured at the ablation area, along with hydrological and meteorological observations. Findings include that the amount of the basal slip accounts a large part of the glacier flow. The measurement of the surface profile revealed that the surface elevation decreased by 42 ± 5 m since 1986, with the mean annual thinning rate of 3.2 ± 5 m.Aerial photographic survey in 1998 of snouts of outlet glaciers of the Northern Patagonia Icefield revealed glacier variations sin … More ce 1995 when it was done last time. All outlet glaciers but one (San Rafael Glacier) are found to have retreated during this period. Aerial photographic survey in 1999 disclosed a very interesting phenomenon. San Rafael Glacier, which was only glacier advancing since 1993, was found to have retreated between 1998 and 1999. From this observation, it is postulated that the unusual advance of San Rafael Glacier may no be attributed to the rainfall increase during the early 1970s as supposed before, but may be attributed to fjord topography and glacier dynamics.In November-December 1999, ice drilling was accomplished at the accumulation area of Tyndall Glacier of the Southern Patagonia Icefield, acquiring ice-core samples of 46 m long, along with in situ observation. Detailed chemical analyses of the ice-core will be done in the near future. At Perito Moreno Glacier, Calving activities were measured with photogrammetric measurements and the amount of calving was estimated by recording tidal waves caused by calving. Bathymetric survey of the lake was also done, revealing the depth near the glacier front down to 80 m deep. The depth of Brazo Upsala, into which Upsala Glacier is flowing, was measured, with the maximum depth close to 700 m. Bathymetric data are important to analyze the relationship between calving activities, glacier dynamics and glacier variations. Less