金沙江上游巴塘-中咱河段位于青藏高原东南缘,该河段两岸岸坡发育众多的大型古滑坡,且部分古滑坡曾堵塞金沙江形成了堰塞湖,特米大型古滑坡堰塞湖是其中之一。关于特米古滑坡堰塞湖的形成与演化过程目前尚未见有过详细的报道。本文在野...金沙江上游巴塘-中咱河段位于青藏高原东南缘,该河段两岸岸坡发育众多的大型古滑坡,且部分古滑坡曾堵塞金沙江形成了堰塞湖,特米大型古滑坡堰塞湖是其中之一。关于特米古滑坡堰塞湖的形成与演化过程目前尚未见有过详细的报道。本文在野外调查的基础上,结合遥感影像解译和年代学测试,对特米古滑坡堰塞湖的地貌和沉积特征进行了详细研究,并对其形成与演化过程进行了分析。研究结果表明,特米古滑坡堰塞湖很可能是由该地区的古地震活动触发大型滑坡并堵塞金沙江形成的,最大湖面面积约为1.42×10^(7) m^(2),库容蓄水量约为1.46×10^(9) m^(3)。该古堰塞湖的形成时间约为1.8 ka BP,其溃决消亡的时间约为1.4 ka BP,溃决洪峰流量约为55858 m^(3)/s,该滑坡堰塞湖持续稳定了约400年的时间。展开更多
岷江上游叠溪古滑坡堰塞湖在地质历史时期(20~30 ka BP之间)发生了多次溃决,并在其下游岷江两岸形成一套规模罕见(长约5 km)的溃坝堆积物。通过现场调查、测量取样和室内筛分试验,分析了溃坝堆积物的物质组成、粒度分布及粒度参数等特...岷江上游叠溪古滑坡堰塞湖在地质历史时期(20~30 ka BP之间)发生了多次溃决,并在其下游岷江两岸形成一套规模罕见(长约5 km)的溃坝堆积物。通过现场调查、测量取样和室内筛分试验,分析了溃坝堆积物的物质组成、粒度分布及粒度参数等特征。结果表明:(1)堆积物主要由砾石、卵石、砂及少量粉/黏土组成;(2)从上段至下段,溃坝堆积物的平均粒径和分选系数逐渐变小,偏度值逐渐变大,且包含了所有的峰态类型;(3)溃坝堆积物各段的粒度频率曲线均为双峰型,概率累积曲线均表现为上凸型,且从上段至下段逐渐变紧凑。这些特征反映了溃坝堆积物物源区以粗砾石/块石为主,且从上段至下段,粗砾石逐渐减少,细粒成分逐渐增加,沉积物的分选性逐渐变好,溃决洪水的水动力强度逐渐减弱。本研究结果对于认识堰塞湖溃坝堆积物沉积特征及沉积环境具有重要指导意义。展开更多
Late Pleistocene glaciation was restricted to only a few high mountains in eastern China. The Gongwang mountains constitute one of the typical places once glaciated. Geomorphic mapping of the area and the TL dating pr...Late Pleistocene glaciation was restricted to only a few high mountains in eastern China. The Gongwang mountains constitute one of the typical places once glaciated. Geomorphic mapping of the area and the TL dating provides evidence for at least four distinct glaciations. YJT-Ⅰ glacial advance occurred about 100 ka BP and two TL absolute ages （101,100 ± 7780 a BP; 104,000± 8300 a BP） indicate this advance happened during the Penultimale Glaciation. The early stage glacial advance （YJT-Ⅱ advance） during the last glaciation occurred about 40,920 ± 3400 a BP. The last glacial maximum advance （YJT-Ⅲ advance） about 18-25 ka BP, which sustained by two TL ages （18,230 ±1420 a BP; 25,420 ± 2110 a BP）. The Penultimale and the early stage glaciations were more extensive and the last glacial maximum （LGM） and the late-glacial period （YJT-Ⅳ advance, 10 ka BP） were progressively less extensive. Correlated with the other mountains in eastern China, these glacial advances in the Gongwang mountains just like the advances in the western part such as Diancang mountains, Yulong mountains of Yunnan Province and the glacier series are more complete than the adjacent mid-latitude regions such as Taibai mountain and Taiwan mountains and are roughly representative of climate changes during the last glacial cycle in Yunnan Province.展开更多
New dates for last glacial cycle in Tibetan bordering mountains and in East Asia show the glacial extent during the early/middle （MIS3-4） stage is larger than that of the late stage （MIS2） in last glacial cycle. I...New dates for last glacial cycle in Tibetan bordering mountains and in East Asia show the glacial extent during the early/middle （MIS3-4） stage is larger than that of the late stage （MIS2） in last glacial cycle. It is asynchronous with the Northern Hemisphere ice sheets maximum and changes in oceanic circulation that predominately control global climate. In research areas, three seasonal precipitation patterns control the accumulation and ablation of glaciers. The modes of the westerlies and the East Asian mountains/islands in and along the Pacific Ocean are favorable to glacier advance with mainly winter precipitation accumulation. There was a global temperature-decreasing phase in the middle stage （MIS3b, 54-44 ka BP）, when the glacier extent was larger than that in Last Glaciation Maximum due to the low temperature combined with high moisture. It is revealed that the Quaternary glaciers not only evolved with localization, but also maybe with globalization. The latest studies show a fact that the developmental characteristics of glaciers in high mountains or islands along the western Pacific Ocean are not in accord with those inland areas. Therefore, it can be concluded that glacier development exhibits regional differences. The study validates the reasonableness of the asynchronous advance theory, and ascertains that both the synchronous and asynchronous advance/retreat of glaciers existed from 30 ka BP to 10 ka BP. It is not suitable to emphasize the synchronicity between global ice-volume and glacier change.展开更多
There are glacial remains of three different periods on the main peak of Snow Mountain in Taiwan province, including cirque lake, crosswall, polished surface, striation, moraine ete. These three different periods were...There are glacial remains of three different periods on the main peak of Snow Mountain in Taiwan province, including cirque lake, crosswall, polished surface, striation, moraine ete. These three different periods were called, respectively, Shanzhuang ((44.25 ± 3.72) kaBP), Shuiyuan ((18.26 ± 1.52) kaBP), and Xueshan glacial stages (the late period of last glaciation). it is characterized by the earlier glacier broad in scale.展开更多
The Changbai Mountains (2749 m a.s.l.) in northeastern China are one of the typical mountain regions with glaciation since late Pleistocene as evidenced by well-preserved erosive and accumulative landforms at elevatio...The Changbai Mountains (2749 m a.s.l.) in northeastern China are one of the typical mountain regions with glaciation since late Pleistocene as evidenced by well-preserved erosive and accumulative landforms at elevations above 2000 m a.s.l. formed by glaciers around the crater lake, Tianchi Lake. Cirque glaciers developed on both the inner and outer sides of the volcanic cone. Well-preserved cirques, glacial trough valleys, glacial threholds, polished surfaces of the glacial erratics and the moraine ridges indicate that several glaciation processes took place during the last glacial period in this region. Results of optically stimulated luminescence (OSL) dating on the moraine sediments, and the K/Ar, ther- mal ionization mass spectrometry (TIMS), electronic spinning resonance (ESR) dating on the volcanic rocks suggest two periods of glacier advances. One is named the Black Wind Mouth glacier advance taking place on the west and north slopes of the volcanic cone at an elevation of 2000―2100 m a.s.l., which is dated to about 20 ka, being the result of the Last Glacial Maximum (LGM). The other is named the Meteorological Station glacier advance at the elevation of 2400―2600 m a.s.l., dated to 11 ka during the late glacial period, and is tentatively correlated to the Younger Dryas stage. The scope of the former glacier advance is larger than that of the latter. Regional comparisons showed that the glacial sequences in the Changbai Mountains are similar to other glaciated areas in eastern Asia during the later part of the last glacial cycle.展开更多
The Kunlun Pass Basin, located in the middle of the eastern Kunlun Mountains, received relatively continuous late Cenozoic sediments from the surrounding mountains, archiving great information to understand the deform...The Kunlun Pass Basin, located in the middle of the eastern Kunlun Mountains, received relatively continuous late Cenozoic sediments from the surrounding mountains, archiving great information to understand the deformation and uplift histories of the northern Tibetan Plateau. The Kunlun-Yellow River Movement, identified from the tectonomorphologic and sedimentary evolution of the Kunlun Pass Basin by Cui Zhijiu et al. (1997, 1998), is roughly coincident with many important global and Plateau climatic and environmental events, becoming a crucial time interval to understand tectonic-climatic interactions. However, the ages used to constrict the events remain great uncertainty. Here, we present the results of detailed magnetostratigraphy of the late Cenozoic sediments in the Kunlun Pass Basin, which show the basin sediments were formed between about 3.6 Ma and 0.5 Ma and the Kunlun-Yellow River Movement occurred at 1.2 to ～0.78 Ma. The lithology, sedimentary facies and lithofacies associations divide the basin into five stages of tectonosedimentary evolution, indicating the northern Tibetan Plateau having experienced five episodes of tectonic uplifts at ～3.6, 2.69－2.58, 1.77, 1.2, 0.87 and ～0.78 Ma since the Pliocene.展开更多
The various types of granite landforms in the Huangshan Mt. are distributed in a concentric pattern. The remaining parts of the planation surface are in the center; domical peaks, castle peaks, pointed peaks, and ridg...The various types of granite landforms in the Huangshan Mt. are distributed in a concentric pattern. The remaining parts of the planation surface are in the center; domical peaks, castle peaks, pointed peaks, and ridges are arranged from the center to the periphery accordingly. This reveals that knick points are still near the center and the center area is the common divide of the radial water system. It is inferred that the granite bodies in the Huangshan Mt. were exposed to erosion in Miocene and Pliocene, and the planation surface was also formed then. After the slight uplift in late Pliocene, a light-incised surface was formed. Then, in early Quaternary, there were intense uplifts and incisions so that deep incised surface was formed. The above process is still in progress, and results in high peaks and deep gorges outside of the center area. However, due to the limited catchment area in the center, headward erosion is mild, and the current landforms in the Huangshan Mt. can be maintained for a long time.展开更多
The authors reviewed the research of planation surface in recent years and commented on the development of method and theory about the planation surface. Some aspects of research, such as the restrictive planation sur...The authors reviewed the research of planation surface in recent years and commented on the development of method and theory about the planation surface. Some aspects of research, such as the restrictive planation surface, the karst planation surface, the fossil planation surface, the dating of weathering crust, the research of weathering crust and environmental evolution, extremely enriched the method and theory of the planation surface. Besides, the authors pointed out that we must take further steps to study the following issues: the deformation of planation surface, the original height of planation surface, the recognition and contrast of the planation surface. The weathering crust and planation surface should be regarded as a whole, and it will still be a principal aspect in the future.展开更多
Upfreezing is an important geomorphic process in the periglacial environment.It is a product of cold climate and thus an important part of the cryospheric processes.Based on the long-term positioning observations in t...Upfreezing is an important geomorphic process in the periglacial environment.It is a product of cold climate and thus an important part of the cryospheric processes.Based on the long-term positioning observations in the source area of the Urumqi River,this article represents an in-depth discussion of the characteristics of sorted circles and upfreezing mechanisms in the Tianshan Mountains.In the source area of the Urumqi River,the intensity of upfreezing is the highest within the top 25 cm near the surface,while targets with a diameter of 3 cm are least affected by upfreezing.There is no distinct difference between the centre with fine grains and the margin with coarse debris within the same sorted circle in terms of the intensity of upfreezing.The correlation analysis demonstrates that temperature plays an important role in upfreezing and the development of sorted circles.A long-time positioning observation of sorted circles reveals that periglacial landforms are sensitive to regional climate change and respond quickly to the temperature increase of the recent two decades.Enhanced upfreezing was found to be due to increased soil moisture content.展开更多
文摘金沙江上游巴塘-中咱河段位于青藏高原东南缘,该河段两岸岸坡发育众多的大型古滑坡,且部分古滑坡曾堵塞金沙江形成了堰塞湖,特米大型古滑坡堰塞湖是其中之一。关于特米古滑坡堰塞湖的形成与演化过程目前尚未见有过详细的报道。本文在野外调查的基础上,结合遥感影像解译和年代学测试,对特米古滑坡堰塞湖的地貌和沉积特征进行了详细研究,并对其形成与演化过程进行了分析。研究结果表明,特米古滑坡堰塞湖很可能是由该地区的古地震活动触发大型滑坡并堵塞金沙江形成的,最大湖面面积约为1.42×10^(7) m^(2),库容蓄水量约为1.46×10^(9) m^(3)。该古堰塞湖的形成时间约为1.8 ka BP,其溃决消亡的时间约为1.4 ka BP,溃决洪峰流量约为55858 m^(3)/s,该滑坡堰塞湖持续稳定了约400年的时间。
文摘岷江上游叠溪古滑坡堰塞湖在地质历史时期(20~30 ka BP之间)发生了多次溃决,并在其下游岷江两岸形成一套规模罕见(长约5 km)的溃坝堆积物。通过现场调查、测量取样和室内筛分试验,分析了溃坝堆积物的物质组成、粒度分布及粒度参数等特征。结果表明:(1)堆积物主要由砾石、卵石、砂及少量粉/黏土组成;(2)从上段至下段,溃坝堆积物的平均粒径和分选系数逐渐变小,偏度值逐渐变大,且包含了所有的峰态类型;(3)溃坝堆积物各段的粒度频率曲线均为双峰型,概率累积曲线均表现为上凸型,且从上段至下段逐渐变紧凑。这些特征反映了溃坝堆积物物源区以粗砾石/块石为主,且从上段至下段,粗砾石逐渐减少,细粒成分逐渐增加,沉积物的分选性逐渐变好,溃决洪水的水动力强度逐渐减弱。本研究结果对于认识堰塞湖溃坝堆积物沉积特征及沉积环境具有重要指导意义。
文摘Late Pleistocene glaciation was restricted to only a few high mountains in eastern China. The Gongwang mountains constitute one of the typical places once glaciated. Geomorphic mapping of the area and the TL dating provides evidence for at least four distinct glaciations. YJT-Ⅰ glacial advance occurred about 100 ka BP and two TL absolute ages （101,100 ± 7780 a BP; 104,000± 8300 a BP） indicate this advance happened during the Penultimale Glaciation. The early stage glacial advance （YJT-Ⅱ advance） during the last glaciation occurred about 40,920 ± 3400 a BP. The last glacial maximum advance （YJT-Ⅲ advance） about 18-25 ka BP, which sustained by two TL ages （18,230 ±1420 a BP; 25,420 ± 2110 a BP）. The Penultimale and the early stage glaciations were more extensive and the last glacial maximum （LGM） and the late-glacial period （YJT-Ⅳ advance, 10 ka BP） were progressively less extensive. Correlated with the other mountains in eastern China, these glacial advances in the Gongwang mountains just like the advances in the western part such as Diancang mountains, Yulong mountains of Yunnan Province and the glacier series are more complete than the adjacent mid-latitude regions such as Taibai mountain and Taiwan mountains and are roughly representative of climate changes during the last glacial cycle in Yunnan Province.
基金N ationalN aturalScience Foundation ofChina,N o.40071015
文摘New dates for last glacial cycle in Tibetan bordering mountains and in East Asia show the glacial extent during the early/middle （MIS3-4） stage is larger than that of the late stage （MIS2） in last glacial cycle. It is asynchronous with the Northern Hemisphere ice sheets maximum and changes in oceanic circulation that predominately control global climate. In research areas, three seasonal precipitation patterns control the accumulation and ablation of glaciers. The modes of the westerlies and the East Asian mountains/islands in and along the Pacific Ocean are favorable to glacier advance with mainly winter precipitation accumulation. There was a global temperature-decreasing phase in the middle stage （MIS3b, 54-44 ka BP）, when the glacier extent was larger than that in Last Glaciation Maximum due to the low temperature combined with high moisture. It is revealed that the Quaternary glaciers not only evolved with localization, but also maybe with globalization. The latest studies show a fact that the developmental characteristics of glaciers in high mountains or islands along the western Pacific Ocean are not in accord with those inland areas. Therefore, it can be concluded that glacier development exhibits regional differences. The study validates the reasonableness of the asynchronous advance theory, and ascertains that both the synchronous and asynchronous advance/retreat of glaciers existed from 30 ka BP to 10 ka BP. It is not suitable to emphasize the synchronicity between global ice-volume and glacier change.
文摘There are glacial remains of three different periods on the main peak of Snow Mountain in Taiwan province, including cirque lake, crosswall, polished surface, striation, moraine ete. These three different periods were called, respectively, Shanzhuang ((44.25 ± 3.72) kaBP), Shuiyuan ((18.26 ± 1.52) kaBP), and Xueshan glacial stages (the late period of last glaciation). it is characterized by the earlier glacier broad in scale.
基金the National Natural Science Foundation of China (Grant No. 40571016)
文摘The Changbai Mountains (2749 m a.s.l.) in northeastern China are one of the typical mountain regions with glaciation since late Pleistocene as evidenced by well-preserved erosive and accumulative landforms at elevations above 2000 m a.s.l. formed by glaciers around the crater lake, Tianchi Lake. Cirque glaciers developed on both the inner and outer sides of the volcanic cone. Well-preserved cirques, glacial trough valleys, glacial threholds, polished surfaces of the glacial erratics and the moraine ridges indicate that several glaciation processes took place during the last glacial period in this region. Results of optically stimulated luminescence (OSL) dating on the moraine sediments, and the K/Ar, ther- mal ionization mass spectrometry (TIMS), electronic spinning resonance (ESR) dating on the volcanic rocks suggest two periods of glacier advances. One is named the Black Wind Mouth glacier advance taking place on the west and north slopes of the volcanic cone at an elevation of 2000―2100 m a.s.l., which is dated to about 20 ka, being the result of the Last Glacial Maximum (LGM). The other is named the Meteorological Station glacier advance at the elevation of 2400―2600 m a.s.l., dated to 11 ka during the late glacial period, and is tentatively correlated to the Younger Dryas stage. The scope of the former glacier advance is larger than that of the latter. Regional comparisons showed that the glacial sequences in the Changbai Mountains are similar to other glaciated areas in eastern Asia during the later part of the last glacial cycle.
基金This work was supported by the National Natu-ral Science Foundation of China(Grand Nos.40421101,40121303,40334038).
文摘The Kunlun Pass Basin, located in the middle of the eastern Kunlun Mountains, received relatively continuous late Cenozoic sediments from the surrounding mountains, archiving great information to understand the deformation and uplift histories of the northern Tibetan Plateau. The Kunlun-Yellow River Movement, identified from the tectonomorphologic and sedimentary evolution of the Kunlun Pass Basin by Cui Zhijiu et al. (1997, 1998), is roughly coincident with many important global and Plateau climatic and environmental events, becoming a crucial time interval to understand tectonic-climatic interactions. However, the ages used to constrict the events remain great uncertainty. Here, we present the results of detailed magnetostratigraphy of the late Cenozoic sediments in the Kunlun Pass Basin, which show the basin sediments were formed between about 3.6 Ma and 0.5 Ma and the Kunlun-Yellow River Movement occurred at 1.2 to ～0.78 Ma. The lithology, sedimentary facies and lithofacies associations divide the basin into five stages of tectonosedimentary evolution, indicating the northern Tibetan Plateau having experienced five episodes of tectonic uplifts at ～3.6, 2.69－2.58, 1.77, 1.2, 0.87 and ～0.78 Ma since the Pliocene.
基金Supported by the National Natural Science Foundation of China (Grant No. 40701017)
文摘The various types of granite landforms in the Huangshan Mt. are distributed in a concentric pattern. The remaining parts of the planation surface are in the center; domical peaks, castle peaks, pointed peaks, and ridges are arranged from the center to the periphery accordingly. This reveals that knick points are still near the center and the center area is the common divide of the radial water system. It is inferred that the granite bodies in the Huangshan Mt. were exposed to erosion in Miocene and Pliocene, and the planation surface was also formed then. After the slight uplift in late Pliocene, a light-incised surface was formed. Then, in early Quaternary, there were intense uplifts and incisions so that deep incised surface was formed. The above process is still in progress, and results in high peaks and deep gorges outside of the center area. However, due to the limited catchment area in the center, headward erosion is mild, and the current landforms in the Huangshan Mt. can be maintained for a long time.
基金This work was supported by the National (Grant No. 1998040800)CAS's Key Project for Bastic Research on Tibetan Plateau (Grant Nos. KZ951-A1-204 and KZ957-06).
文摘The authors reviewed the research of planation surface in recent years and commented on the development of method and theory about the planation surface. Some aspects of research, such as the restrictive planation surface, the karst planation surface, the fossil planation surface, the dating of weathering crust, the research of weathering crust and environmental evolution, extremely enriched the method and theory of the planation surface. Besides, the authors pointed out that we must take further steps to study the following issues: the deformation of planation surface, the original height of planation surface, the recognition and contrast of the planation surface. The weathering crust and planation surface should be regarded as a whole, and it will still be a principal aspect in the future.
基金supported by the National Natural Science Foundation of China(40971002 and 41101003)
文摘Upfreezing is an important geomorphic process in the periglacial environment.It is a product of cold climate and thus an important part of the cryospheric processes.Based on the long-term positioning observations in the source area of the Urumqi River,this article represents an in-depth discussion of the characteristics of sorted circles and upfreezing mechanisms in the Tianshan Mountains.In the source area of the Urumqi River,the intensity of upfreezing is the highest within the top 25 cm near the surface,while targets with a diameter of 3 cm are least affected by upfreezing.There is no distinct difference between the centre with fine grains and the margin with coarse debris within the same sorted circle in terms of the intensity of upfreezing.The correlation analysis demonstrates that temperature plays an important role in upfreezing and the development of sorted circles.A long-time positioning observation of sorted circles reveals that periglacial landforms are sensitive to regional climate change and respond quickly to the temperature increase of the recent two decades.Enhanced upfreezing was found to be due to increased soil moisture content.
