大布苏湖全新世沉积岩心的碳酸盐含量与湖面波动   总被引：21，自引：1，他引：21  

介冬梅  吕金福  李志民  冷雪天  王升忠  张桂荣 《海洋地质与第四纪地质》2001,21(2):77-82

大布苏湖是我国东北地区极为罕见的盐湖，通过对该湖现代湖盆碳酸盐沉积相的分析，以及钻孔岩心碳酸盐含量和^14C年代的测定,探讨了大布苏湖全新世湖面波动与环境演化的过程。结果表明，大布苏湖有两次高湖面时期，分别为10450－7260和5400－3600aBP，湖泊水位稳定在125m以上，这两个时期也是松嫩沙地古土壤集中发育的时期，晚全新世以来，大布苏湖明显萎缩，气候向干燥方向转化。  相似文献   

巢湖沉积物粒度特征与沉积环境   总被引：9，自引：0，他引：9  

顾成军  戴雪荣  张海林  何小勤 《海洋地质前沿》2004,20(10):10-13

利用巢湖湖底柱样沉积物的粒度资料分析了巢湖湖底沉积物粒径的组成、大小等粒度特征;初步探讨了柱样采样点位置的沉积环境及其沉积过程,以期能为巢湖流域恢复过去环境变化提供参考。通过对沉积物粒度实验分析发现,巢湖靠近河口地区的沉积物粒度在深度上变化幅度大,颗粒物相对较粗,而在湖心位置,沉积物随深度变幅小、连续性好,沉积物的颗粒细。两者的差别分别反映了它们之间不同的沉积环境。  相似文献   

新疆库车盆地古近纪—新近纪盐湖成钾与靶区预测     

刘成林  曹养同  徐洋  焦鹏程  姚佛军 《地质学报》2024,98(3):941-956

库车前陆盆地位于塔里木盆地北部,属于副特提斯域,古近纪受副特提斯海海水补给,古近纪—新近纪发育巨厚蒸发岩。研究显示,库车盆地始新世和中新世古盐湖卤水已演化至钾盐析出阶段,在地层中广泛发现了原生钾盐矿物,如钾石盐、光卤石、杂卤石等;通过岩芯岩屑地球化学及矿物学分析,基本确定了至少3个富钾层或成钾层位,其中始新统中上部两个和中新统中上部一个,钾离子含量最高达3%,另外,上新统可能存在一个成钾层位。本文在综述此前库车盆地构造、蒸发岩、盐类矿物学、地球化学与盐湖沉积等研究基础上,建立了新的库车盆地古盐湖构造- 沉积演变、成钾模式;提出了4个钾盐成矿区带,即北部克拉苏成矿带、中部秋里塔克成矿带、南部沙雅构造沉降成矿带以及东部阳霞凹地成钾区,这些关键认识为库车盆地的钾盐勘查提供了重要的理论和科学依据。  相似文献   

A Late Quaternary lake record from the Qilian Mountains (NW China): lake level and salinity changes inferred from sediment properties and ostracod assemblages   总被引：5，自引：0，他引：5  

S. Mischke  U. Herzschuh  C. Zhang  J. Bloemendal  F. Riedel   《Global and Planetary Change》2005,46(1-4):337

Two sediment cores (length 13.94 and 12.93 m) have been drilled from the small alpine Lake Luanhaizi in the eastern central Qilian Mountains and correlated by means of magnetic susceptibility (MS). This paper focuses on the lithology and chronology of the longer core, on the results of loss on ignition (LOI), element concentration, thermomagnetic as well as magnetic hysteresis loop measurements, and on the ostracod record.The recovered sediments represent three types of depositional environment: a shallow intermittent lake, a deeper permanent lake and a true playa lake. Three stages of a higher lake level and permanence of the water body are reconstructed. The lowermost stage of a permanent lake and inferred favourable environmental conditions occurred probably about 45 ¹⁴C ka BP. The second stage of a deeper permanent lake occurred either shortly before or, more likely, following the LGM. Most favourable environmental conditions and highest water levels were reconstructed for the uppermost stage comprising the Holocene. Considering the lake record, glaciers have not reached the lake site at 3200 m altitude during the LGM, providing further evidence against a large ice sheet on the Tibetan Plateau.  相似文献   

A paleolimnological record of anthropogenic disturbances at Holmes Lake,Adirondack Mountains,New York     

Thomas E. Rhodes 《Journal of Paleolimnology》1991,5(3):255-262

Holmes Lake, Adirondack Mountains, New York, is a clear-water acidic lake that was treated with lime in 1983 to permit stocking of trout. Diatom assemblages in dated sediments reflect three anthropogenic modifications of the lake ecosystem: 1) assemblages from the mid- and late 1800's are associated with historical and sedimentary records of forest clearance, and indicate slightly increased pH; 2) acidobiontic species increase in sediments from the mid-1900's, a period of local reforestation and regionally increasing anthropogenic acid loading; 3) liming caused large increases of circumneutral periphytic species in the first growing season, and decreases of acidobiontic species by the second.  相似文献   

High‐energy sedimentation,Creag Aoil,Spean Bridge,Scotland: implications for meltwater movement and storage during Loch Lomond Stadial (Younger Dryas) ice retreat     

Andrew J. Russell  Fiona S. Tweed  Tim Harris 《第四纪科学杂志》2003,18(5):415-430

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Heavy metal research in lacustrine sediment： a review   总被引：2，自引：0，他引：2  

姚志刚  高璞 《中国海洋湖沼学报》2007,25(4):444-454

Heavy metals are released into environment from a wide range of natural and anthropogenic sources. Aquatic ecosystems are normally at the receiving end and in many cases, with lakes as intermediaries. Lacustrine sediments are important sinks for heavy metals and play a significant role in enrichment and remobilization of heavy metals in aquatic systems. Therefore, characteristics of heavy metal in lacustrine sediments become one of the important issues in environmental sciences. Progress in heavy metal research of lake sediments since late 1980s is reviewed comprehensively in this paper from over 100. The Highlights are placed on the establishment of aquatic sediment quality guidelines, references chemical speciation of heavy metals, heavy metal transport mechanisms in lakes, and high-resolution study of lake borehole cores. Meanwhile, suggestions for heavy metal research in lacustrine sediment in the future are proposed, including such issues as using integrated approaches to assess aquatic ecosystem, modem lake dynamic process, high-resolution evolutionary sequence and spatial differentiation of environments and international lake database, which should be referential to the promotion of research on heavy metal in aquatic system.  相似文献   

Coastal lake records add constraints to the age and magnitude of the Younger Dryas ice‐front oscillation along the Skagerrak coastline in southern Norway     

Anders Romundset  Thomas R. Lakeman  Fredrik Hgaas 《第四纪科学杂志》2019,34(2):112-124

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Changes in glacial lakes and glaciers of post-1986 in the Poiqu River basin, Nyalam, Xizang (Tibet)   总被引：16，自引：0，他引：16  

Xiao-qing Chen  Peng Cui  Yong Li  Zhong Yang  Yong-qing Qi 《Geomorphology》2007,88(3-4):298-311

Glacial lakes and glaciers are sensitive indicators of recent climate change. In the Poiqu River basin of southern Tibet, 60–100 km NW of Mt. Everest, Landsat imagery defines post-1986 changes in the size and distribution of both glacial lakes and glaciers. Total area of glaciers in the 229-km² drainage area has decreased by 20%. The number of glacial lakes with areas in excess of 0.020 km² has increased by 11%, and the total area of glacial lakes has increased by 47%. The areas of typical large glacial lakes of the area (Galongco, Gangxico, and Cirenmaco) have increased by 104, 118, and 156%, respectively, and these increases are confirmed by field investigations.Comparing the 1986 data, the area of glaciers in the basin headwaters has decreased by 46.18 km² to a present total area of 183.12 km², an annual rate of change of 3.30 km²/year. Trends indicate that the total area of glaciers will continue to decrease and that both the numbers and areas of glacial lakes will continue to increase. Accompanying these trends will be an increased risk of debris flows, formed by entrainment of sediment in glacial-outburst floods and in surges from both failure and avalanche- and landslide-induced overtopping of moraine dams. Based on both the local and world-wide history of catastrophes from flows of these origins, disaster mitigation must be planned and appropriate engineering countermeasures put in place as soon as possible.  相似文献   

Siliceous algae-based seasonal temperature inference and indicator pollen tracking ca. 4,000 years of climate/land use dependency in the southern Austrian Alps     

Roland Schmidt  Christian Kamenik  Monika Roth 《Journal of Paleolimnology》2007,38(4):541-554

Diatom and chrysophyte cyst-based reconstructions of the dates of spring and autumn lake-mixing enabled us to estimate spring (ST_anom) and autumn (AT_anom) temperature anomalies as well as ice-cover of the last ca. 4,000 years in a lake sediment core (Oberer Landschitzsee, 2,076 m a.s.l.) from the southern slopes of the Austrian Central Alps. The two independently inferred temperature anomalies were significantly correlated. On average, spring and autumn temperatures were lower during the two millennia B.C than during 0–1,300 A.D. Marked spring and autumn temperature minima occurred at about 1,300 and 600 B.C. At about 1,300 A.D, ST_anom declined again. Spring-temperature anomalies during Roman and Medieval times equaled or slightly exceeded the modern values and paralleled tree-line and glacier fluctuations. The de-coupling of autumn and spring climates, which began during the Medieval period, might indicate changes in major circulation modes. It was assumed that the North-Atlantic influence, triggering winter-rain climate in the Northern Mediterranean, became weaker during Medieval times, resulting in a trend towards warmer autumns and overall more continental climate conditions in the study area. Four pulses of land use, inferred from indicator pollen, occurred during (1) the Early to Late Bronze, (2) the transition from Late Bronze to Early Iron Age (Hallstatt), (3) Late Iron Age (La Tène, Celtic time) to Roman times, and (4) during high to late Medieval times. Climate seemed to be an important, though complex, trigger of Alpine land use.  相似文献