Glacial Runoff Likely Reached Peak in the Mountainous Areas of the Shiyang River Basin,China

Glacier runoff in mountain areas of the Shiyang River Basin(SRB), Qilian Mountain, western China is important for the river and water supply downstream. Small glaciers with area of less than 1km2 are dominant(87%) in the SRB. A modified monthly degree-day model was applied to quantify the glacier mass balance, area, and changes in glacier runoff in the SRB during 1961–2050. The comparison between the simulated and observed snow line altitude, annual glacier runoff, and mass balance from1961 to 2008 suggests that the degree-day model may be used to analyze the long-term change of glacier mass balance and runoff in the SRB. The glacier accumulation shows a significant(p<0.01) decreasing trend of-0.830 mm a-1. The mass balance also shows a significant(p<0.01) decreasing trend of-5.521 mm a-1. The glacier total runoff has significantly(p<0.05)increased by 0.079 × 105 m3 from 1961 to 2008. The monthly precipitation and air temperature are projected to significant(p<0.005) increase during2015 to 2050 under three different scenarios. The ablation is projected to significant(p<0.001) increase,while the accumulation has no significant(p=0.05)trend. The mass balance is projected to decrease, theglacier area is projected to decrease, and the glacier runoff depth is projected to increase. However, the glacier total runoff is projected to decrease. These results indicate that the glacier total runoff over glacier areas observed in 1970 reached its peak in the 2000 s. This will exacerbate the contradiction between water supply and downstream water demands in the SRB.

Winter and summer monsoonal evolution in Gonghe Basin, northeastern Qinghai-Tibetan Plateau since the Last Glacial Maximum

Geochemical and grain size analysis on the DQ （Dongqi） profile from Gonghe Basin, northeastern Qinghai-Tibetan Plateau, indi- cates that regional climate has experienced several cold-dry and warm-wet cycles since the last glacial maximum （LGM）. The cold and dry climate dominated the region before 15.82 cal. ka B.E due to stronger winter monsoon and weaker summer monsoon, but the climate was relatively cold and wetter prior to 21 cal. ka B.E. In 15.824.5 cal. ka B.E, summer monsoon strength in- creased and winter monsoon tended to be weaker, implying an obvious warm climate. Specifically, the relatively cold and dry condition appeared in 14.7-13.7 cal. ka B.E and 12.14.5 cal. ka B.R, respectively, while relatively warm and wet in 13.~12.1 cal. ka B.E. The winter and summer monsoonal strength presents frequent fluctuations in the Holocene and relatively warm and wet conditions emerged in 9.5~.0 cal. ka B.E due to stronger summer monsoon. From 7.0 to 5.1 cal. ka B.E, the cycle of cold-dry and warm-wet climate corresponds to frequent fluctuations of winter and summer monsoons. The climate becomes warm and wet in 5.1 2.7 cal. ka B.E, accompanying increased summer monsoon, but it tends to be cold and dry since 2.7 cal. ka B.R due to en- hanced winter monsoonal strength. In addition, the evolution of regional winter and summer monsoons is coincident with warm and cold records from the polar ice core. In other words, climatic change in the Gonghe Basin can be considered as a regional re- sponse to global climate change.

Moraine-dammed glacial lake changes during the recent 40 years in the Poiqu River Basin,Himalayas

Glacier retreat is not only a symbol of temperature and precipitation change, but a dominating factor of glacial lake changes in alpine regions, which are of wide concern for high risk of potential outburst floods. Of all types of glacial lakes, moraine-dammed lakes may be the most dangerous to local residents in mountain regions. Thus, we monitored the dy- namics of 12 moraine-dammed glacial lakes from 1974 to 2014 in the Poiqu River Basin of central west Himalayas, as well as their associated glaciers with a combination of remote sensing, topographic maps and digital elevation models （DEMs）. Our results indicate that all monitored moraine-dammed glacial lakes have expanded by 7.46 km2 in total while the glaciers retreated by a total of 15.29 km2 correspondingly. Meteorological analysis indicates a warming and drying trend in the Nyalam region from 1974 to 2014, which accelerated glacier retreat and then augmented the supply of moraine-dammed glacial lakes from glacier melt. Lake volume and water depth changed from 1974 to 2014 which indicates that lakes Kangxico, Galongco, and Youmojanco have a high potential for outburst floods and in urgent need for continuous moni- toring or artificial excavation to release water due to the quick increase in water depths and storage capacities. Lakes Jialongco and Cirenmaco, with outburst floods in 1981 and 2002, have a high potential risk for outburst floods because of rapid lake growth and steep slope gradients surrounding them.

Decadal glacial lake changes in the Koshi basin, central Himalaya, from 1977 to 2010, derived from Landsat satellite images

Changes in glacial lakes and the consequences of these changes, particularly on the development of water resources and management of glacial lake outburst flood(GLOF) risk, has become one of the challenges in the sustainable development of high mountain areas in the context of global warming. This paper presents the findings of a study on the distribution of, and area changes in, glacial lakes in the Koshi basin in the central Himalayas.Data on the number of glacial lakes and their area was generated for the years 1977, 1990, 2000, and 2010 using Landsat satellite images. According to the glacial lake inventory in 2010, there were a total of 2168 glacial lakes with a total area of 127.61 km^2 and average size of 0.06 km^2 in the Koshi basin. Of these,47% were moraine dammed lakes, 34.8% bedrock dammed lakes and 17.7% ice dammed lakes. The number of glacial lakes increased consistently over the study period from 1160 in 1977 to 2168 in 2010, an overall growth rate of 86.9%. The area of glacial lakes also increased from 94.44 km^2 in 1977 to 127.61 km^2 in 2010, a growth rate of 35.1%. A large number of glacial lakes in the inventory are small in size(≤ 0.1km^2). End moraine dammed lakes with area greater than 0.1 km^2 were selected to analyze the change characteristics of glacial lakes in the basin. The results show that, in 2010, there were 129 lakes greater than 0.1 km^2 in area; these lakes had a total area of 42.92km^2 in 1997, increasing to 63.28 km^2 in 2010. The distribution of lakes on the north side of the Himalayas(in China) was three times higher than on the south side of the Himalayas(in Nepal).Comparing the mean growth rate in area for the 33 year study period(1977-2010), the growth rate on the north side was found to be a little slower than that on the south side. A total of 42 glacial lakes with an area greater than 0.2 km^2 are rapidly growing between 1977 and 2010 in the Koshi basin, which need to be paid more attention to monitoring in the future and to identify how critical they are in terms of GLOF.

张掖盆地晚更新世至中全新世气候变化:孢粉学和重矿物学证据

为确定张掖盆地晚第四纪沉积地层时代和探讨其蕴含的古气候信息,笔者利用孢粉分析、重矿物分析、光释光测年等方法对研究区晚更新世以来气候变化特征进行了重建,并确认了当地全新世和晚更新世地层界限。结果表明:地层自下而上划分为4个孢粉组合带和植被类型及气候特征:①深度为56.8~26.4 m,年龄为112.7~63.3 ka,属末次间冰期,粉组合为松–板栗–藜–菊–蒿,针阔叶混交林草原植被,为晚更新世温暖较湿润气候。②深度为26.4~2.6 m,年龄为63.3~11.8 ka,与末次冰期相当,孢粉组合为松–麻黄–藜–蒿,植被类型为针阔叶混交林草原植被,为晚更新世干燥寒冷气候。③深度为2.6~0.8 m,年龄为11.8~8.9 ka,全新世早期,孢粉组合为松–藜–蒿,稀树针阔叶混交林草原植被,较凉较干气候。④深度为0.8~0.15 m,年龄为8.9~7.8 ka,全新世早期向中期过渡期,孢粉组合为松–藜–菊–蒿,稀树针阔叶混交林草原植被,为温暖较干气候。孢粉组合所揭示的晚更新世—中全新世气候变化特征,对于揭示张掖盆地甚至西北干旱区的古气候变化具有重要意义。

四川盆地及周缘前震旦系裂谷特征与油气地质意义

四川盆地及周缘已被证实发育较大规模的前震旦系裂谷,但其在盆地内部的展布及发育特征尚不明确,因此在一定程度上制约了对盆地深部构造格局的认识。为此,在前人研究的基础上,利用最新的重磁电资料,通过联合解译和小子域滤波等新技术对新元古界构造形态进行了研究,同时结合区域地震大剖面的精细解释并辅以航磁资料进行验证,分析了新元古代裂谷的特征及其对上覆地层的沉积控制作用。研究结果表明:①盆地内部自西北至东南共发育3条近乎平行的前震旦系裂谷,其中以川中裂谷规模最大;②裂谷内部发育一系列与裂谷走向近平行的次级正断层,将裂谷内部结构复杂化,形成一系列断陷;③裂谷内断层在平面上呈平行/斜列式、相向/相背平行式及同向平行式组合,对应在剖面上呈阶梯式、垒堑式、地堑式及铲式半地堑式等组合特征;④盆地东北部盆缘露头揭示南华系—陡山沱组在裂谷内发育冰期—间冰期交互沉积,主要为三角洲、陆棚与斜坡盆地相碎屑岩和冰碛岩。结论认为,应用重磁联合解译+井震资料修订+露头剖面验证的新方法,证实四川盆地前震旦系裂谷的存在,且南华纪裂谷边界(主干)断裂控制了上覆地层沉积古地理格局和坡折带的发育,部分裂谷控制了寒武系或早古生界沉积中心的分布,并对后期沉降中心、构造圈闭的形成以及含油气系统有着极为重要的影响。

Snow disaster characteristics in Palongzangbu River Basinand mitigation countermeasures for road engineering

The Palongzangbu River Basin contains the highest number of maritime province glaciers in China. There are 130 glacial lakes, 64 snow avalanche sites and 28 glacial debris flow gullies distributed within the basin. Snow disasters play a controlling role in the Sichuan-Tibet Highway construction, due to the terrain’s special characteristics of high altitude and large height differential. Segmentation mitigation countermeasures for the Sichuan-Tibet Highway are presented based on snow disaster severity level and damage mode of the road. In the Ranwu to Midui section, snow avalanches are regional disasters, so the line should be placed in sunny slopes. In the Midui Gully to Yupu section, the line should be placed in shady slopes and at higher elevations to reduce the risk of glacial lake outburst. In the Yupu to Guxiang section, all three snow disasters are minimal. In the Guxiang to Tongmai section, glacier debris flows are the major threat, thus the road should be placed in shady slopes.

A PRELIMINARY STUDY ON QUATERNARY GLACIAL LANDFORMS IN MT.MA'AN

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Hydrodynamic processes and depositional styles of glacierassociated deposits in the Moxi basin, Southwest China

This study aims to understand the particle size distribution and depositional styles of glacierassociated deposits in the Moxi basin in southwest China. Based on field surveys, 28 samples from glacier-associated deposits(including glacial till,fluvioglacial, debris flow, river and lake deposits)were collected and tested in the laboratory. The results showed that the glacier-associated deposits can be differentiated based on particle gradation,particle size distribution and accumulated percentages. We evaluated the evolution of a former dammed lake in the Moxi basin based on glacierassociated deposits. The results of this study also indicated that the Moxi Platform was not formed by a single depositional process but is composed of both fluvioglacial and debris flow deposits. This research shows that the depositional style analysis is useful in identifying different glacier-associated deposits in high mountain regions. Moreover, the evaluation of the differences in particle sizes of the glacierassociated deposits is useful in reconstructing geohazard events in periglacial regions, and this information can help in identifying and reducing the potential risks associated with geo-hazards.

帕隆藏布流域冰川泥石流易发性研究

帕隆藏布流域地处藏东南高海拔,高地应力,高烈度,高地温的地形急变带,现代海洋性冰川分布,流域内冰川泥石流频发,合理评价流域内冰川泥石流易发性对工程建设具有重要意义。考虑到目前流行的机器学习算法应用的局限性,采用因子分析和证据权模型相耦合的方法建立易发性评估模型。将帕隆藏布划分为169个子流域,通过遥感解译和现场调查确定泥石流发育情况,并选取14个与冰川泥石流相关的影响因子进行分析。结果表明:冰川泥石流极高易发区集中在帕隆藏布干流古乡至通麦段、波堆藏布上游段、瓤达曲小流域段,共包括104个子流域,总流域面积为2308.4 km^(2),占所有子流域面积的24%。

冰川流域孕灾环境及灾害的天空地协同智能监测模式与方向

随着中国西部暖湿化进程加快,冰川流域孕灾环境快速变化,冰川灾害多发频发。因冰川流域地形极端复杂、地表覆盖变化迅速,冰川流域灾害具有链式发展的特点且物源区远程高位、地势险峻,面向普通地质滑坡和露天矿边坡的天空地协同监测技术难以直接或有效应用。本文基于冰川流域空间环境与灾害的监测内容及技术难点,分析了可用的现代测绘遥感技术及其局限性。针对监测对象、几何要素和质量要求,提出了基于天空地协同的冰川流域孕灾环境与灾害智能监测内涵,即平台协同、时间协同、参数协同和尺度协同,设计了任务驱动、知识引导的智能监测技术模式。面向3类基本监测任务,即个体冰川流域灾变过程情景模拟、冰川流域群孕灾环境差异分析与风险识别、冰川流域灾害事件应急响应,提出相应的天空地协同智能监测初步方案。最后,讨论了基于天空地协同的冰川流域孕灾环境与灾害智能监测关键问题,提出未来的工作方向。

西藏西部札达盆地早更新世香孜组沉积特征和时代——对青藏高原第四系底界的约束

通过对西藏札达盆地及其周缘的野外地质调查,填绘出了大面积分布的早更新世早期香孜组冰缘区河湖相沉积。对该河湖相沉积的岩石、结构构造、沉积环境、所含化石特征和形成时代等的研究表明,它是第四纪冰期冰缘区的最早沉积记录,也是第四纪冰期的下限。为青藏高原建立气候地层层序、第四纪冰期划分对比提供了重要的实际资料和依据。

西藏札达盆地及周缘高山区第四纪冰川堆积及冰川进退规程讨论

札达盆地及周缘高山区的第四纪冰川堆积在空间分布上大致可分为:①盆地周缘高山区U形谷中及山麓地带的冰川堆积;②盆地周边深切峡谷区的冰川堆积;③盆地面上的冰川堆积;④盆地河谷高阶地与沟谷中的冰川堆积;⑤盆地周缘高山区山前地带的冰川堆积等。不同区域分布的冰川堆积,在砾石成分、磨圆度、结构构造、地貌特征等都有较明显区别。依据冰川堆积物的特征、分布等,可将本区第四纪的冰川发展,由老到新划分为:冰缘阶段→冰进阶段→最大冰川阶段→冰退阶段。对应的冰川类型为:山谷、山麓及冰帽冰川发育阶段→大规模冰帽冰川发育阶段→冰帽、山谷及山麓冰川发育阶段。现有资料研究表明,札达盆地及周缘高山区,是青藏高原第四纪冰川堆积发现最多、最全、分布最连续和保存最好的地区。为该区及青藏高原地区的第四纪冰川研究、冰期的划分和对比、气候地层的建立、古气候和古环境的研究等提供了珍贵的基础资料。

华南扬子地区新元古代地层划分对比研究新进展

华南扬子地区发育有新元古代完整的沉积地层记录,是研究我国新元古代时期古大陆演化与沉积盆地演替的天然平台。四堡—晋宁造山运动（约850~820Ma）以前,新元古代早期的扬子陆块总体上处于弧陆碰撞与弧后前陆盆地充填阶段。约820Ma以后,新生裂谷盆地开启了新一轮板块构造旋回,至约635Ma,华南扬子陆块走过了一段冰与火的不平坦里程。板溪群沉积期（约820~720Ma）,在Rodinia超大陆裂解的构造背景下,伴随着三幕重要的火山岩浆事件,沉积了一套裂谷盆地充填序列。板溪晚期,由于Rodinia超大陆主要陆块的裂离（Drifting）,伴随着区域性海平面下降,迎来了南华大冰期的长安冰期沉积;实际上,南华大冰期并非严格的＂雪球地球＂,而且期间还存在一个间冰期（富禄间冰期）;随后,可能与海平面持续的海侵上超有关,南沱冰期沉积区域展布广泛。由此可见,华南扬子地区晋宁—四堡造山后至南华冰期,沉积序列、事件序列特征明显,阶段性清楚,为新元古代地层划分对比提供了基础条件。

玛纳斯河流域冰川变化及水资源研究进展

玛纳斯河流域地处西北内陆干旱区,由于水资源制约社会经济发展和生态环境建设,近年来也取得了很多高水平的研究成果。按流域上游产流区和中下游消耗区对以往研究进行总结,以期对流域冰川变化及水资源方面有更清晰的认知,主要从冰雪覆盖变化、河川径流变化特征及其对气候变化的响应、径流变化的模拟预测、地下水、同位素、水资源的开发利用等方面综合概述了研究区水资源的研究进展。近半个世纪以来,玛河流域上游区开展了一些冰川野外考察工作,对流域冰川的形成、作用有了初步的认识,但缺少冰川变化方面的实测数据。在全球变暖的影响下,研究区冰川面积出现了不同程度的缩减,并导致冰川生态系统服务功能价值下降;近60年来研究区气温和降水都呈递增趋势,流域年径流变化受水文年降水量、夏季温度、永久性冰川雪地面积变化等综合影响,其中径流量波动上升与气温和降水呈正相关,流域主要依赖冰雪消融和地下水补给;流域水资源承载力呈现良性发展的态势,能够维持生态系统的正常功能。但研究区由于资源性缺水和生产生活用水不断加剧,水资源日益成为区域经济社会发展的制约因素,众多学者从不同层面提出了水资源开发利用和管理方面的对策和建议。但目前的研究中仍存在一些问题和不足,重点可以在流域冰川水资源的系统研究、建立冰川变化的定位观测体系和开展详细的流域冰川模拟预测研究,要在中下游区加强社会经济用水和生态用水的科学调配等方面展开进一步研究。

塔里木盆地东部南华系-寒武系黑色岩系地球化学特征及形成与分布

近年来,随着油气勘探向深层-超深层领域拓展,古老层位的烃源岩逐渐成为研究热点。塔里木盆地周缘广泛出露的前寒武地层为古老烃源岩及其发育背景研究提供了基础。本文主要介绍了塔东地区南华系、震旦系和寒武系三套烃源岩,通过对库鲁克塔格地区野外露头及岩芯资料的综合分析,采用有机地球化学和无机地球化学手段对烃源岩质量以及烃源岩发育环境进行了评价,认为南华系特瑞艾肯组、震旦系水泉组、寒武系西大山组为主要烃源岩发育层位。特瑞艾肯组烃源岩TOC分布在0.22%~2.80%,平均值1.65%,Ro平均值为1.28%~1.60%;水泉组烃源岩TOC分布在0.22%~0.79%,平均值为0.49%;Ro分布在1.37%~1.93%之间(均值1.72%);西大山组烃源岩TOC分布在0.15%~1.45%,平均值0.47%。结合地震资料对裂陷结构进行追踪,初步对塔里木盆地东部三套烃源岩的分布范围进行了限定。针对塔里木盆地新元古代盆地演化背景,运用C、O、Sr同位素及微量元素等,对三套黑色岩系形成环境与发育机制进行分析;并对库鲁克塔格地区的冰期事件进行了的限定,认为塔东地区南华-寒武纪至少发生过三期冰期事件,塔东地区冰碛岩地层的划分可以为全球前寒武地层对比提供依据。

基于GIS的玛旁雍错流域冰川地貌及现代冰川湖泊变化研究

基于多源多时相的数字遥感影像、地形图和DEM数据,利用遥感(RS)和地理信息系统(GIS)技术,对西藏玛旁雍错流域冰川地貌类型和空间分布进行了研究,并对流域内近30 a来冰川和湖泊的变化进行分析.结果表明:1974—2003年玛旁雍错流域冰川总面积减少了7.27 km2,平均退缩速率0.24 km2.a-1;湖泊总面积减少37.58 km2,平均退缩速率1.25 km2.a-1.多时相的监测表明,冰川在加速退缩,且阳坡冰川的消融速度大于阴坡,坡度陡、面积小的冰川消融比例大于坡度缓、面积较大的冰川;湖泊面积先减少后有所增加,但总面积还是减少了,不少小湖泊消失.分析流域附近气象资料可知,气温上升和降水量减少是玛旁雍错流域内冰川消融与退缩的主要原因.

山地冰川演化与冰湖发育相互作用机制

冰川-冰湖耦合过程是冰冻圈物质与能量循环的重要组成部分,系统刻画冰川演化与冰湖发育过程的相互作用机制,对于完善冰冻圈科学理论体系和认知冰川作用区变化规律、水循环模式和灾害效应具有重要意义。本文立足山地冰川演化和冰湖发育过程,系统归纳了冰川-冰湖相互作用研究进展,剖析了冰川作用与冰湖发育耦合机制及相关模型的应用,并对现有冰川演化与冰湖发育过程耦合机制研究存在的不足与挑战进行解析和总结。冰川-冰湖耦合过程的深入研究有助于提高数值模拟的可信度与精度,为评估冰川-冰湖耦合过程影响、建立灾害监测预警体系和采取适应性措施提供数据与理论基础。

末次冰期以来柴达木盆地沙漠形成与演化

通过热释光测年,结合剖面岩性岩相特征、粒度等环境指标的综合分析,对柴达木盆地各地形面上古风成砂剖面进行了详细分析研究。将柴达木盆地沙漠形成与演化划分为3个阶段:21～15 kaBP的末次盛冰期是柴达木盆地大规模沙漠活动时期;15～10 kaBP的晚冰期柴达木盆地沙漠经历了多次扩展和固定缩小的波动演化;10 kaBP以来的全新世盆地沙漠经历了固定缩小和再次扩张的演化过程。自21 kaBP末次盛冰期以来,随着全球气候的波动变化,盆地沙漠虽经历了多次扩展与固定缩小的两相组合式波动演化过程,但流沙活动至今尚未完全停止过。现今盆地流沙活动是末次盛冰期以来沙漠演化过程中新近经历的又一阶段,是末次盛冰期流沙活动的承袭。

西北干旱区石羊河流域末次冰期晚期气候不稳定性记录

通过对我国西北干旱区石羊河流域三角城末次冰期最盛期晚期 -晚冰期地层剖面沉积物中有机质碳同位素分析 ,表明在季风边缘带的沉积地层中较详细地记录了这一时期气候快速颤动 ,发生千年至百年尺度的冷干—温湿变化 ,高分辨的有机质碳同位素组成与GRIP氧同位素组成有较好的可比性 ,表明与全球古气候变化有明显的联系 ,也反映在末次冰期最盛期与晚冰期过渡期气候温湿 ,陆地植被比较发育 ,可能与东亚季风有关。有机质碳同位素这一指标对气候记录较敏感 ,是重建干旱区高分辨古气候演化模式十分有效的手段 ,在季风交汇带能灵敏地记录到气候快速变化。