Pleistocene Glaciations Along the Eastern Foot of the Yulong Mountains
Pleistocene Glaciations Along the Eastern Foot of the Yulong Mountains
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发表时间：
1999
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通讯作者：
Zhao Xi-tao
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作者：
Zhao Xi-tao
玉龙山脉位于云南省丽江县北部，青藏高原东南缘，海拔27°10′~27°40′N，100°9′~100°20′E，是中国和欧亚大陆最南端的冰川山脉，沿着其东、东北、西麓，研究这些冰川遗迹，重建它们的演化历史，不仅具有重要的科学意义，对认识冰川、气候和环境的变化，探讨横断山和青藏高原的隆升，金沙江流域的发展和亚洲季风的形成与发展，具有重要的科学意义，对开发和保护该地区巨大的水力资源和旅游资源也具有重要的实用价值。根据1∶10 000地形图和航片，对玉龙山东麓沿着更新世冰川沉积进行了研究和制图，测定了冰川、河冰沉积和钙质冰湖沉积中钙质胶结物样品的ESR年龄，将其划分为四个冰川期，即中更新世早期玉龙冰期（07 ~ 06 MaBP），中更新世中期干海子冰川作用（053 ~ 045 MaBP），中更新世晚期丽江冰期（0.31 ~ 0.13MaBP）和晚更新世大理冰期，研究结果表明，玉龙山地区是青藏高原至云南的联合平原的一部分，中新世，贵州高原，海拔500~ 1000 m上新世-早更新世，断裂活动使玉龙山脉隆升，丽江盆地、大巨盆地、龙蟠谷等盆地沉降。中更新世早期，玉龙山脉隆升越过雪线，玉龙冰川的巨大皮埃蒙特冰川，干海子冰川也是皮埃蒙特，但规模比前者小得多。在随后的大间冰期，龙蟠谷和大居盆地成为两个湖泊，中更新世晚期和晚更新世晚期，在金沙江支流中发育了较大规模的丽江冰川和大理冰川的河谷冰川
Yulong Mountains (27°10′～27°40′N, 100°9′～100°20′E), situated in the north of Lijiang County, Yunnan Province and the southeast margin of the Tibetan Plateau, are the southernmost mountains with glaciers both in China and Eurasia Along their east, northeast and west feet, there is a series of relics of the Pleistocene glaciation Studying these glaciation relics and reconstructing their history of evolution have not only an important scientific implication for understanding the changes of glaciation, climate and environment and for discussing the uplift of the Hengduan Mountains and the Tibetan Plateau, as well as the development of the Jinsha River valley and the formation and development of Asian monsoon, but also major practical values for developing and protecting the tremendous resources of hydraulics and tourism in this area The authors survey, research and map the Pleistocene glacial deposits along the eastern foot of the Yulong Mountains based on the topographic map with the scale of 1∶10 000 and air-photographs, determining ESR dates of samples of calcareous cements from the glacial and fluvioglacial deposits as well as the calcareous glacio-lacustrine deposits, dividing them into four glaciations, i e the early Middle Pleistocene Yulong Glaciation (0 7～0 6 Ma BP), the middle Middle Pleistocene Ganhaizi Glaciation (0 53～0 45 Ma BP), the late Middle Pleistocene Lijiang Glaciation (0 31～0 13 Ma BP) and the Late Pleistocene Dali Glaciation, and correlating them with the glaciations on the Tibetan Plateau Results of study show that the Yulong Mountains area was a part of the united peneplain from the Tibetan Plateau to the Yunnan-Guizhou Plateau, 500～1 000 m a s l , during the Miocene In the Pliocene and the Early Pleistocene, the Yulong Mountains uplifted and the Lijiang Basin, Daju Basin, Longpan Valley and other basins subsided due to the fault activities In the early Middle Pleistocene, the Yulong Mountains had uplifted over the snowline, and giant piedmont glaciers of the Yulong Glaciation, the largest glaciation in this area, occurred at their east, west and northeast feet The glaciers in the Ganhaizi Glaciation were also piedmont ones, but muchsmaller than the former During the following grand interglacial, the Longpan Valley and the Daju Basin became two lakes, and then cut by the modern Jinsha River In the late Middle Pleistocene and the Late Pleistocene, the larger-scale valley glaciers of the Lijiang and Dali Glaciations developed in the tributaries of the Jinsha River