Suspended sediment transport and deposition in a high arctic meromictic lake     

Michael J. Retelle  Jonathan K. Child 《Journal of Paleolimnology》1996,16(2):151-167

A study of sedimentary processes and sediment yields in a high arctic meromictic lake (Lake C2, Taconite Inlet, Northern Ellesemere Island, Canada) was undertaken from May 1990 through August 1992 to understand the links between climatic controls, hydrology, and the laminated sediment record preserved in the lake. Understanding the relationships between processes and the sediment record is critical for interpreting the climatic significance of the laminated sediments in a region where high resolution climate proxy records are quite limited.Sediment transport to Lake C2 is dominated by fluvial processes. During the early part of the melt season slushflows transport sediment to the lake surface. Subsequently, suspended sediment is delivered to the lake by the main inlet stream and distributed lakeward by a plume emanating the main inlet channel. Due to the strong density stratification of the water column the plume distributes sediment downlake by overflows and interflows in the epilimnion. In general, overflows are generated by lower discharge events whereas interflows penetrate to the halocline during high discharge with increased suspended sediment concentration.Sediment trap analysis demonstrates that suspended sediment transport and deposition responds to diurnal through annual changes in stream discharge. Seasonal and annual sediment trap yields agree with average accumulation rates determined from varve thickness measurements and cumulative suspended sediment discharge from the main inlet stream indicating a close link between climatological, hydrological, and sedimentological controls and varve deposition.This is the fourth in a series of papers published in this issue on the Taconite Inlet Lakes Project. These papers were collected by Dr R. S. Bradley.  相似文献   

新疆盐湖卤水成分及其成因   总被引：15，自引：0，他引：15  

郑喜玉  刘建华 《地理科学》1996,16(2):115-123

根据野外考察和室内研究资料，论述了新疆盐湖的概况，卤水主要和次要成分，盐湖的水化学类型。探讨了盐湖卤水化学成分的来源和集散特点。  相似文献   

可可西里地区湖泊资源调查研究   总被引：17，自引：0，他引：17  

胡东生 《干旱区地理》1992,15(3):50-58

1989—1990年,国家可可西里综合考察填补了青藏高原腹地最后一块空白区。通过24个专业学科历时两年的奋战,取得了大量珍贵的第一性科学资料,基本查清了可可西里地区湖泊资源及其展布规律,湖泊度达0.047—0.053;并发现了本区特有的湖泊奇特景观。为可可西里地区自然环境演变过程中湖泊时空位置的揭示,湖泊的保护利用、开发管理以及国土整治等提供了科学依据。  相似文献   

The fauna of the Aral Sea in 1989. 2. The zooplankton     

N. I. Andreev  I. S. Plotnikov  N. V. Aladin 《International Journal of Salt Lake Research》1992,1(1):111-116

Data are presented on the composition and biomass of the Aral Sea zooplankton in August and October, 1989. As salinity gradually increased, a decrease in zooplankton species composition occurred at a salinity of 25–30 g L⁻¹. Because the Aral has now divided into two water-bodies, the zooplankton communities in these lakes have begun to conform with their individual hydrological and biological regimes.  相似文献   

层序地层学方法及其在陆相湖盆研究中的应用   总被引：29，自引：2，他引：29  

余素玉  邬金华 《地质科技情报》1993,12(2):37-43

针对中国中、新生代陆相湖盆的特征,从沉积盆地的构造和边缘背景对海相层序地层的影响出发,讨论了湖水面相对变化、沉积物供给、气候等对湖相层序地层的控制作用,明确指出两种背景条件具有本质差异,海相层序地层学方法不能简单套用于内陆盆地分析。  相似文献   

盐湖相低熟油脂肪酸的组成与分布特征   总被引：7，自引：4，他引：3  

张松林  崔明中  李振西  王有孝  范璞 《沉积学报》1999,17(1):130-155

对泌阳凹陷碱性盐湖相、舞阳凹陷盐湖相、襄城凹陷膏盐湖相、南阳凹陷淡水湖相低熟油脂肪酸组成和分布特征进行了分析与研究。结果表明这些不同盐湖相的低熟原油的脂肪酸为丰度不同的饱和正构酸、不饱和正构酸、少量异构酸、类异戊二烯酸及脂肪酸乙酯系列化合物。脂肪酸的组成和分布反映了原始有机质的来源。  相似文献   

Analysis of the influence of Taihu Lake and the urban heat islands on the local circulation in the Yangtze Delta   总被引：6，自引：0，他引：6  

李维亮  刘洪利  周秀骥  秦瑜 《中国科学D辑(英文版)》2003,46(4):405-415

The influences of human activities on regional climate and weather are tremendous. The re-gional temperature and the distributing of wind field are influenced, whereas the precipitation in-tensity and the spatial and temporal distribution of the precipita…  相似文献   

Methane in an acidic bog lake: The influence of peat in the catchment on the biogeochemistry of methane   总被引：3，自引：0，他引：3  

Peter Casper  On Chim Chan  Andre L. S. Furtado  Donald D. Adams 《Aquatic Sciences - Research Across Boundaries》2003,65(1):36-46

  相似文献   

Chemostratigraphy of Lago Albano sediments (Central Italy):geochemical evidence of palaeoenvironmental changes in lateQuaternary     

Federico Lucchini  E. Dinelli  N. Calanchi 《Journal of Paleolimnology》2003,29(1):109-122

The results of the geochemical investigation on bulk sediment fromthree cores collected in Albano crater lake (Central Italy) are reported, andthe main markers of the palaeoenvironmental changes in the last 26ka are discussed. The sediment of Lago Albano consists of greysilt and mud, and is made of volcanogenic, calcareous, siliceous and organicmaterial. Some tephra layers provide a chronological framework for thesequence. The chemical features of the sediments are strongly impacted by theAlban Hills volcanism (Roman volcanic area), but there are also strong changesof organic/inorganic matter ratios, owing to variations in biologicalproductivity and terrigeous supply from the catchment. Six chemostratigraphiczones record the main steps of the transition from the cold and dry climate ofGlacial Maximum to the warmer and more humid Holocene climate. The most usefulgeochemical indices are: biogenic silica, CO₂, Br and organiccontent (OM) for biological productivity; Al, Y, CIA (Chemical Index ofAlteration), Al/Rb, Ti/Zr and Y/Al ratios for terrigenous clasticmaterial; OM/Al ratio for organic/terrigenous ratio; S/Fe andMo/Fe ratios and Authigenic U for redox diagenetic conditions of the lakesediment. The geochemical records agree rather well with those of thelithological and paleomagnetic studies, and despite the information obtainedare less detailed than those acquired by the study of biological remains, thepalaeoenvironmental significance inferred is consistent. A comparison of thechemostratigraphic results of Lago Albano with those obtained on coevalsediments from Central and Southern Italy lakes supports the role of thegeochemical investigation as important complement to more sophisticatedtechniques in the palaeoenvironmental reconstructions.  相似文献   

Influence of vegetation change on watershed hydrology: implications for paleoclimatic interpretation of lacustrine δ18O records     

Michael F. Rosenmeier  David A. Hodell  Mark Brenner  Jason H. Curtis  Jonathan B. Martin  Flavio S. Anselmetti  Daniel Ariztegui  Thomas P. Guilderson 《Journal of Paleolimnology》2002,27(1):117-131

Stratigraphic shifts in the oxygen isotopic (¹⁸O) and trace element (Mg and Sr) composition of biogenic carbonate from tropical lake sediment cores are often interpreted as a proxy record of the changing relation between evaporation and precipitation (E/P). Holocene ¹⁸O and Mg and Sr records from Lakes Salpetén and Petén Itzá, Guatemala were apparently affected by drainage basin vegetation changes that influenced watershed hydrology, thereby confounding paleoclimatic interpretations. Oxygen isotope values and trace element concentrations in the two lowland lakes were greatest between ~ 9000 and 6800 ¹⁴C-yr BP, suggesting relatively high E/P, but pollen data indicate moist conditions and extensive forest cover in the early Holocene. The discrepancy between pollen- and geochemically-inferred climate conditions may be reconciled if the high early Holocene ¹⁸O and trace element values were controlled principally by low surface runoff and groundwater flow to the lake, rather than high E/P. Dense forest cover in the early Holocene would have increased evapotranspiration and soil moisture storage, thereby reducing delivery of meteoric water to the lakes. Carbonate ¹⁸O and Mg and Sr decreased between 7200 and 3500 ¹⁴C-yr BP in Lake Salpetén and between 6800 and 5000 ¹⁴C-yr BP in Lake Petén Itzá. This decline coincided with palynologically documented forest loss that may have led to increased surface and groundwater flow to the lakes. In Lake Salpetén, minimum ¹⁸O values (i.e., high lake levels) occurred between 3500 and 1800 ¹⁴C-yr BP. Relatively high lake levels were confirmed by ¹⁴C-dated aquatic gastropods from subaerial soil profiles ~ 1.0–7.5 m above present lake stage. High lake levels were a consequence of lower E/P and/or greater surface runoff and groundwater inflow caused by human-induced deforestation.  相似文献