博斯腾湖流域气候及湖陆风   总被引：8，自引：0，他引：8  

王容  杜勇 《干旱区地理》1994,17(3):90-94

通过流域多个气象站的资料，分析了流域气候条件，并通过对湖区测点的气象观测资料与陆区测点－ 焉耆站的同步资料对比分析，讨论了博斯腾湖区域小气候其湖陆风特征。  相似文献   

A note on the chemical composition of lake water in the Laguna Amarga,a saline lake in Patagonia,Chile     

Y. Saijo  O. Mitamura  M. Tanaka 《International Journal of Salt Lake Research》1995,4(2):165-167

The chemical composition of lake water in Laguna Amarga, a small, shallow, saline lake near the Torres del Paine National Park (at 51°S), Chilean Patagonia, was studied in January, 1993. The water was strongly alkaline (pH 9.4) conductivity was 71.4 mS cm^–1, and salinity was 77 g L^–1. The major ions were sodium and sulphate.  相似文献   

Coastal Massachusetts pond development: edaphic,climatic, and sea level impacts since deglaciation     

Marjorie Green Winkler  Patricia R. Sanford 《Journal of Paleolimnology》1995,14(3):311-336

Kettle ponds in the Cape Cod National Seashore in southeastern Massachusetts differ in their evolution due to depth of the original ice block, the clay content of outwash in their drainage basins, and their siting in relation to geomorphic changes caused by sea-level rise, barrier beach formation, and saltmarsh development. Stratigraphic records of microfossil, carbon isotope, and sediment changes also document late-glacial and Holocene climatic changes.The ponds are separated into 3 groups, each of which follow different development scenarios. Group I ponds date from the late-glacial. They formed in clay-rich outwash, have perched aquifers and continuous lake sediment deposition. The earliest pollen and macrofossil assemblages in Group I pond sediments suggest tundra and spruce-willow parklands before 12 000 yr B.P., boreal forest between 12 000 and 10 500 yr B.P., bog/heath initiation and expansion during the Younger Dryas between 11 000 and 10 000 yr B.P., northern conifer forest between 10 500 and 9500 yr B.P., and establishment of the Cape oak and pitch pine barrens vegetation after 9500 yr B.P. Sedimentation rate changes suggest lowered freshwater levels between 9000 and 5000 yr B.P. caused by decreased precipitation on the Atlantic Coastal Plain. Lake sediment deposition began in the middle Holocene in Group II ponds which formed in clay-poor outwash. These ponds date from about 6000-5000 yr B.P. In these ponds sediment deposition began as sea level rose and the freshwater lens intersected the dry basins. The basal radiocarbon dates of these ponds and stable carbon isotope analyses of the pond sediments suggest a sea-level curve for Cape Cod Bay. Holocene topographic changes in upland and the landscape surrounding the ponds is reconstructed for this coastal area.Group III ponds in the late Holocene landscape of the Provincelands dunes originated as interdunal bogs about 1000 yr B.P. and became ponds more recently as water-levels increased. Peat formation in the Provincelands reflects climatic changes evident on both sides of the Atlantic region.This is the 8th in a series of papers published in this special AMQUA issue. These papers were presented at the 1994 meeting of the American Quaternary Association held 19–22 June, 1994, at the University of Minnesota, Minneapolis, Minnesota, USA. Dr Linda C. K. Shane served as guest editor for these papers.  相似文献   

A sedimentary facies model for perennial and meromictic saline lakes: Holocene Medicine Lake Basin, South Dakota, USA     

Blas L. Valero-Garcés  Kerry R. Kelts 《Journal of Paleolimnology》1995,14(2):123-149

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Spatial uniformity of sediment accumulation in varved lake sediments in northern Sweden     

G. Petterson  I. Renberg  P. Geladi  A. Lindberg  F. Lindgren 《Journal of Paleolimnology》1993,9(3):195-208

As part of an investigation aimed at assessing the potential of northern Swedish varved lake sediments for fine-resolution reconstruction of past climatic conditions, the following questions were addressed; how representative is a single core, does the appearance of varves change as the sediment ages, and how can varve thickness and within-varve structures be digitized? Analyses of replicate cores from Kassjön, using sample sequences of seasonal, annual and centennial time resolution, show that spatial variability of sediment accumulation in the varved sediment is very low. Comparisons of intensity curves from image analysis of freeze cores of recent sediments from Lake Nylandssjön, sampled in 1980 and 1985, indicate that the varves acquire their appearance at the sediment-water interface during sedimentation and that the varve structures are preserved during diagenetic processes. Measurement of varve thicknesses with a tree-ring microscope and with image analysis gave similar results. However, with image analysis, within-varve structures such as colour variations and thicknesses of seasonal layers, can also be recorded, increasing the possibilities for palaeolimnological and palaeoclimatic inferences.  相似文献   

第二代航磁黄沙坪异常的分解及其矿产新空间     

蔡家雄 《湖南地质》1990,9(2):1-9

本文采用同时具有识別、分解、解释异常三重作用的三元解释法■,在黄沙坪异常负值区有效地提取了由未知的深源磁性体引起的剩余异常。该异常与已知的中、浅源磁性体分处于极为类同的成矿地质背景中。后者与隐伏岩体、铅锌多金属盲矿体之间有着密切的成生联系。这为前者间接找矿提供了有力的依据。定量解释结果中,两者间的磁矩等效关系,论证了已知矿床西侧深部空间里,仍存在找到又一个大型矿床的前景。  相似文献   

吉林省南部下元古界集安群地质特征与沉积期古环境分析   总被引：5，自引：0，他引：5  

王福润 《吉林地质》1991,10(2):31-41

根据集安群地质特征,岩石化学,稳定同位素特征分析认为:蚂蚁河组沉积期古环境为强氧化泻湖相;荒岔沟组沉积期为强还原的泻湖相、大东岔组沉积期为开阔正常浅海潮坪相。集安群从发生发展到结束古环境演化规律是:构造上,由优地槽向冒地槽演化,气候上由炎热向温湿演化;古地理环境从有障壁的局限海变为无障壁的开阔海;从咸化海向正常海,从泻湖相向潮坪相转化。  相似文献   

东台吉乃尔盐湖卤水的相化学研究（Ⅱ）—冬夏季卤水蒸发实验   总被引：1，自引：0，他引：1       下载免费PDF全文

张宝全  刘铸唐 《盐湖研究》1994,2(3):27-34

为了研究东台吉乃尔盐湖卤水蒸发时的相化学，确定钾、镁和锂盐的结晶特性，在实验室内２５℃等温蒸发实验基础上和自然条件下进行了冬夏季日晒蒸发试验．东台吉乃尔盐湖卤水是由氯化钠饱和的多组分复杂体系构成的．卤水中存在的离子是Ｎａ＋、Ｋ＋、Ｍｇ２＋、Ｌｉ＋、Ｃａ２＋、Ｂ３＋、ＳＯ４２－和Ｃｌ－．试验数据与Ｎａ＋、Ｋ＋、Ｍｇ２＋Ｃｌ－、ＳＯ４２－ＫＨ２Ｏ五元体系介稳平衡数据进行了讨论和比较．Ａｕｔｅｎｒｉｅｔｈ相图被用来表示各数据间的关系和证明冬夏季蒸发时结晶行为的差别．  相似文献   

The fate of Chernobyl radiocesium in the River Öre catchment,northern Sweden     

Louise Malmgren  Mats Jansson 《Aquatic Sciences - Research Across Boundaries》1995,57(2):144-160

A¹³⁷Cs-balance for the catchment of the River Öre in central northern Sweden which received about 30 kBq m^–2 of radiocesium from the Chernobyl accident was calculated for the period 1986–1991. Altogether, slightly less than 10% of the total deposition in the catchment was estimated to be exported from the terrestrial parts during this period of time. More than 90% of this loss is transported with the River Öre to the outer sea of the Gulf of Bothnia. The retention in Lake Örträsket which is the only lake along the river course and the Öre Estuary outside the river mouth was thus slightly less than 10%. Nearly all of the radiocesium deposited in the lake is permanently retained in the sediments and successively covered with less radioactive sediment. A considerable export of radiocesium from the estuary to the outer sea takes place due to resuspension and subsequent transport by wind and wave generated currents.  相似文献   

High resolution time series of lead and zinc in sediments of Lake Constance   总被引：3，自引：0，他引：3  

Martin Wessels  Angela Lenhard  Federico Giovanoli  Andreas Bollhöfer 《Aquatic Sciences - Research Across Boundaries》1995,57(4):291-304

Sediments in Lake Constance have been dated by radiometric methods and lamination counting. Investigations into the concentrations of lead and zinc in the sediments were carried out to get detailed information about environmental history. Maximum concentrations were found at the beginning of the 1960's. The lead maximum contamination occurred 3 years before the zinc maximum and has an unidentified source. The use of coal, leaded gasoline or the remobilization within the sediment could be excluded to result in the lead maximum. The fluctuations in zinc contamination could be explained with increasing and decreasing pollution (industry, coal burning, building of sewage plants). The greatest fluctuations of both metals occur during periods of great change in the economic history of Germany.  相似文献