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1.
During CHINARE-22 in austral summer of 2005-2006, a lake sediment core named DG4, which is impacted by penguin droppings, was retrieved from a lake catchment in Gardner Island of Vestfold Hills, East Antarctica. In this study, the concentrations of characteristic elements in the core, local bedrocks and fresh penguin guanos were determined. P, Se, F, S, As, Sr and Cu in DG4 were identified as the bio-element assemblage by R-clustering analysis and compared with those in the local bedrocks and fresh guanos, the results are similar to Y2 in Ardley Island, Antarctic Peninsula. On this basis, P and Se were identified as the optimum bio-elements in DG4 and F, P and S were identified in Y2, respectively. This work will provides the foundation for reconstructing the past penguin populations in Gardner Island of Vest- fold Hills, East Antarctica and comparing the penguin population dynamics between East Antarctica and Antarctic Peninsula.  相似文献   

2.
Compared with traditional chemical analysis methods, reflectance spectroscopy has the advantages of speed, minimal or no sample preparation, non-destruction, and low cost. The present study explored the application of the reflectance spectroscopy within near ultraviolet-visible-near infrared region to predict bio-element compositions in the ornithogenic sediments from the maritime Antarctic. A total of 106 samples were taken from four ornithogenic sediment cores on the Ardley Island of Antarctica, 68 samples were used for building calibration equation, and 38 for prediction of nine bio-elements including P, Ca, Cu, Zn, Se, Sr, Ba, F and S. Three multivariate statistical analysis techniques, including stepwise multiple linear regression (Stepwise-MLR), principal component regression (PCR) and partial least squares regression (PLS) were used to develop mathematical relationships between the spectral data and the chemical reference data. The results showed that the regression models constructed by PCR and PLS models have no significant differences, and obviously supervisor to Stepwise-MLR. The correlations between spectra-predicted and chemically analyzed concentrations of nine bio-elements are statistically significant, and the concentration-versus-depth profiles predicted from reflectance spectra using PLS calibration model are consistent with those from actual chemical analysis. These results demonstrated the feasibility of using reflectance spectroscopy to infer bio-element concentrations in the ornithogenic sediments, and thus it is suggested that the reflectance spectroscopy could provide a rapid and valuable technique to indirectly identify whether the sediments were influenced by penguin droppings in the Antarctic region.  相似文献   

3.
During the 2006/07 Antarctic summer, the species population, distribution and reproductive behavior of penguins in areas near the Great Wall Station were investigated. Five species of penguin were recorded: gentoo penguin (Pygoscelis papua), adelie penguin (P. adeliae), chinstrap penguin (P. antarctica), King penguin (Aptenodytes patagonicus) and Emperor penguin (A. forsteri). The first three species bred locally, while the other two species were observed occasionally. Ardley Island is one of the most important breeding areas for penguins. After the breeding season of 2006/07, there were a total of about 17 234 penguins and the breeding success rate was 0.40-141. Comparing with historical data, changes in penguin species populations and distribution were analyzed, and their relationships with the environment, climate change and human activity were investigated.  相似文献   

4.
Valuable geological and environmental information can be obtained from the 200 m thick lacustrine sediments in the Diexi lake(an ancient landslide-dammed lake) of the Minjiang River. The shaking table test method was employed to study the disturbance phenomena which occurred in the Diexi lake sediments. The results show that the disturbance phenomena were caused by liquefaction-induced flows in the unconsolidated lacustrine sediments, due to triggering by earthquakes. The deformations only occurred in unconsolidated sediment layers and not in consolidated layers. This means that a consolidated layer cannot be liquefied and disturbed again by an earthquake for a second time. The disturbance on one layer corresponds to only one earthquake. The temporal occurrence of earthquakes could be determined by disturbance layers generated at different ages. In total, 10 disturbed layers were found in the lacustrine sediments of the Diexi lake. The experiments showed that there were more than 10 earthquakes between 30 ka B.P. and 15 ka B.P. in the Diexi lake area based on the dating of the disturbed sediment layers.  相似文献   

5.
The concentrations of rare earth elements(REEs) in the bulk sediment of Core X2, which was collected from southeastern Hainan Island, were analyzed to investigate the relative contributions of various provenance regions since mid-Holocene. The results show that sediments in Core X2 were primarily derived from Hainan Island with lesser amounts from Taiwan and limited input from the Pearl River. Based on the application of quantitative inversion to model the REE data, the average contributions of river materials from southeastern Hainan Island and southwestern Taiwan to the study area were 68% and 32%, respectively. Furthermore, starting at 4.0 kyr BP, the transport of fluvial sediments from Taiwan to the study region increased due to enhanced hydrodynamics in South China Sea(SCS). These results indicate that the contributions of mountain river materials from Hainan Island and Taiwan to the continental shelf of northern SCS are non-negligible. Furthermore, these results demonstrate that mountain rivers can play an important role in the material cycle of continental margins and may feature a greater impact than large river systems in specific continental shelf areas.  相似文献   

6.
The Jianggang Harbour-centered radial sand ridge (RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element (REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters ((La/Yb)N, (La/Sm)N and (Gd/Yb)N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, δEu, (La/Yb)N, (Gd/Yb)N and (La/Sm)N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of (La/Yb)N, (La/Sm)N and La contents differing from those of the Chinese and Korean river sediments.  相似文献   

7.
对我国东部地区早第三纪是否发生过海侵的争论已经持续２０ 余年。随着研究的深入，人们不断对海相指相化石（ 有孔虫、沟鞭藻、钙质超微化石等） 、特殊的指相矿物（ 海绿石、膏盐） 和地球化学特征（ 微量元素、稳定同位素） 的海相指相意义提出怀疑。对我国西部地区晚新生代盐湖沉积的研究说明，上述指标只能反映水体盐度，东部早第三纪含油盆地没有经历海侵，其生油岩应为内陆咸化湖泊沉积。  相似文献   

8.
Ｉ．ＩＮＴＲＯＤＵＣＴＩＯＮＭｏｓｔｖｏｌｃａｎｏｅｓａｒｅｄｉｓｔｒｉｂｕｔｅｄｉｎｎｏｒｔｈｅａｓｔｏｆＣｈｉｎａ．Ｔｈｅｖｏｌｃａｎｉｃｅｒｕｐｔｉｏｎｓｃａｎｃｈａｎｇｅｔｈｅｇｅｎｅｒａｌｍｏｒｐｈｏｌｏｇｉｃｃｏｎｆｉｇｕｒａｔｉｏｎｏｆ...  相似文献   

9.
Sediment cores with length of 25 - 45cm at 12 stations in Zhujiang(Pearl) River Estuary were sampled in summer of 1999. Chemical components (Al2O3 , Fe2O3, CaO, TiO2, Cu, Pb, Cr, Zn, Co, Ni, V, Ba, Sr and Y) and grain sizes were analyzed. Sediments in Zhujiang River Estuary are characterized by relatively coarse grain size. The grain sizes of the sediments in the area outside the estuary are relatively finer than those in the north part of the estuary but coarser than those in the middle of Lingdingyang and have a trend similar to the spatial distribution trend of some chemical components such as Fe2O3, Al2O3, TiO2, V, Cu, Ni, Zn and Y. This showed that grain size is an important factor that controls the spatial distribution and depth profile of chemical elements in the Zhujiang River Estuary. Frequent re-suspension, re-transportation and redistribution of settled sediment on estuary floor could be deduced from the spatial distributions and depth profiles of chemical components. Except for CaO and Sr, the chemical components always enrich at the west side of, in the middle of, and at the north side of, the estuary. Fe2O3, Al2O3, Ti, V, Cr, Ni, Zn, Cu and Y in Zhujiang River Estuary sediments mainly result from rock and soil weathering except that parts of Cr, Ni, Zn Cu and Y are anthropogenic. CaO and Sr in sediments originate from marine source. Although Co as well as Pb derives from anthropogenic sources, human activities related to Co might differ from the activities related to Pb.  相似文献   

10.
Clay minerals of surface sediments in the South China Sea (SCS) are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis (GSTA) model. Results show that clay mineral types in various sedimentary environments have different sediment sources and transport routes. Sediments in the northern SCS (north of 20°N) between the southwest of Taiwan Island and the outer mouth of the Pearl River have high contents of illite and chlorite, which are derived mainly from sediments on Taiwan Island and/or the Yangtze River. Sediments from the Pearl River are characterized by high kaolinite and low smectite content, and most are distributed in the area between the mouth of the Pearl River and northeast of Hainan Island and transported vertically from the continental shelf to the slope. Characterized by high illite content, sediments from Kalimantan Island are transported toward the Nansha Trough. Sediments from Luzon Island are related with volcanic materials, and are transported westwards according to smectite distribution. On the Sunda Shelf, sediments from the Mekong River are transported southeast in the north while sediments from the Indonesian islands are transported northward in the south. Ascertaining surface sediment sources and their transport routes will not only improve understanding of modern transportation and depositional processes, but also aid paleoenvironmental and paleoclimatic analysis of the SCS.  相似文献   

11.
In an earlier study of the Diexi ancient dammed lake along the Minjiang River in Southwest China, 10 disturbed layers with envelope and flame structures were found in more than 240 m of lacustrine sediments. In this paper, the soft-sediment disturbances caused by earthquakes in the Diexi ancient dammed lake were studied based on field investigations and laboratory core observations. A two-to three-degree-of-freedom spring-type earthquake simulation vibration table was used to carry out disturbance tests on lacustrine sediments under different dynamic conditions. The results support the following conclusions:(1) The disturbance layers in the lacustrine sediments were caused by strong earthquakes in the region.(2) The characteristics of the disturbance layers are related to the seismic parameters and the degree of sediment consolidation.(3) The greater the earthquake intensity is, the greater the disturbance amplitude is; moreover, the lower the consolidation degree is, the greater the disturbance amplitude.(4) The simulation tests verify that the disturbance layers in the sediments of the Diexi ancient dammed lake correspond to strong earthquakes in the region. These results are valuable for ongoing palaeoseismic research in the region.  相似文献   

12.
According to palaeoclimatic and modern instrumental data, numerous studies have indicated that the Arctic climate has undergone a significant warming during the past 100 years, and this may lead to significant impact on the fragile lake ecosystem. In this study, we collected a lake sediment core from the Ny-(A)lesund of Svalbard and determined the concentrations of four pigments including chlorophyll derivatives, total carotenoids, oscillaxanthin and myxoxanthophyll in the sediments. Combined with other physical and chemical proxies such as calcium carbonate, total organic carbon, biogenic silicon etc., we have reconstructed the historical changes of lacustrine primary productivity in Ny-(A)lesund, especially for the past 100 years. The results showed that during the period of Little Ice Age (LIA), the climate was unfavorable for the growth of the lake algae, and thus the lacustrine productivity declined. This result was supported by the relatively low contents of pigment and biogenic silica in the sediments. In contrast, the contents of total organic carbon (TOC) and sediment pigments increased significantly in the upper 5 cm (~1890AD), reflecting the rapid growth of the lake algae, thus the great increase of lacustrine primary productivity, corresponding to the warming climate after LIA. However, the biogenic silica in the upper sediments still had a relatively low level, and this might be related to the growth competition with other algae species. Over the past 100 years, the ratio of Osc/Myx in the sediments decreased continuously, indicative of durative increase of myxoxanthophyll in blue-green algal pigments, and this might imply that the human activity had enhanced the nutrition level of the lake in the Arctic region.  相似文献   

13.
Heavy metal research in lacustrine sediment： a review   总被引：2，自引：0，他引：2  
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   

14.
Radionuclide dating techniques characterized by137Cs and210Pbex have recently been applied in the study of lake sediments around the world.In this study,a chronological series of sediment cores was established based on137Cs and210Pbex analyses along with the evaluation of sediment properties,such as particle size distribution,total organic carbon(TOC),carbonate content,and acid-insoluble residue,to study sediment accumulation rates,sediment sources,and responses to human activities in the Jiuzhaigou National Nature Reserve in southwestern China.In terms of the particle size distribution of sediments,silt content was the highest,and clay and sand contents were relatively low.The sediments displayed high TOC contents because of the significant amounts of vegetation grown in the lakes.The carbonate content was also high due to the overall geological background of carbonates in Jiuzhaigou.Carbonate content tended to decline from top to bottom in the sediment cores,whereas the acid-insoluble residue tended to increase.These results suggested that the depth variation of the environmental parameters of the sediments in two lakes in Jiuzhaigou would correspond to each other.The results indicated that the sediment rate of Jiuzhaigou was generally high with strong siltation,indicating that serious soil loss was induced by intensive human activities in the basin over the past decades.The increases in the mass accumulation rate,contents of acid-insoluble residue,and mean particle size during the periods of 1840–1900s,late 1930s–early 1950s,1966–1978,and2003–2006 revealed the occurrence of severe soil and water loss as a result of extensive agricultural expansion,large-scale deforestation,and road construction in Jiuzhaigou.The deposition rate and the properties of lacustrine sediments could reflect the significant impact of human activities on lake sedimentation during Jiuzhaigou′s history.  相似文献   

15.
A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard （for the trace elements）. The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% （n=12）.  相似文献   

16.
《山地科学学报》2020,17(10):2497-2511
The Diexi ancient dammed lake is in the upper reaches of the Minjiang River. Six terraces with lacustrine sediments occur at the base. These terraces are the products of the graded outburst of the Diexi ancient dammed lake. The outburst of the ancient dammed lake would certainly have had an impact on the Chengdu Plain in the lower reaches of the Minjiang River. In this paper, on-site sampling and laboratory analysis were used to analyze the sediments of the Diexi ancient dammed lake and the Jinsha site in Chengdu Plain, and the environmental indicators of each sediment layer were tested. Through a comparative analysis of the environmental indicators in the sediments at the two locations, the following results were obtained: the palaeoclimatic and palaeoenvironmental characteristics at the two locations generally show consistent changes. The most important finding is that the types and content of the major pollen taxa at the two locations are similar. The Pinus content strongly proves that the soil layers at the Jinsha site was sourced from the upper reaches of the Minjiang River. Considering that the demise of the ancient culture at the Jinsha site occurred close in time to the outburst of the ancient dammed lake, this similarity suggests that the cultural change at the Jinsha site may have been related to the outburst of the Diexi ancient dammed lake.  相似文献   

17.
Numerous lakes in western China are excellent sites for understanding environmental change. However, what dominates rare earth element(REE) variations are still under debate in the lake environmental research. In this study, we selected 28 surface sediment samples from 17 lakes(i.e. largescale lakes, small water bodies, etc.) in the QinghaiTibet Plateau and Xinjiang area. These samples were analyzed to reveal the behavior of the REEs and major elements. These REE patterns are characterized by light rare earth element(LREE) enrichment, weak Ce anomaly(0.84-0.98, 0.94 on average) and negative Eu anomaly(0.53-1.00, 0.67 on average). The homogeneous REE patterns may reflect similar REE of the source lithologys. However, the REE abundances showed some significant differences. In this study, water chemistry data analyses inferred that the highly REE values appear possibly in the saltwater lake, and also related to carbonate mineral, whereas p H played a minor role in REE concentrations. In large-scale lakes(e.g. Lake Bosten and Lake Ulungur), the results showed that the relatively larger REE values are in the margins of lakes. Moreover, lower REE contents are towards the central region. Comprehensive study suggested that five major factors control the REE contents:(1) The REE tends to increase with the increase of the weathering intensity.(2) Likewise, heavy mineral(i.e. rutile, anatase, zircon, etc.) are probably primary in these sediments because they are highly enriched in the REE.(3) The contribution of Fe-Mn oxides is significant in sediments because their concentrations highly correlate with the REE.(4) The carbonate mineral(mainly calcite) played a significant role on the REE values in the lakes because the REEs are incorporated into the carbonate minerals generating the low REE concentrations.(5) Major element analysis, mineral analysis, and grain-size data analysis showed that the REE distribution is chiefly influenced by finer grain-size component of lake sediments due to the decreasing proportion of quartz and feldspar than coarser one. Moreover, the clay minerals in finer grain-size sediments can highly absorb the REE.  相似文献   

18.
ＡＮＮＵＡＬ　ＬＡＭＩＮＡＴＩＯＮＳ　ＩＮ　ＴＨＥ　ＳＥＤＩＭＥＮＴＳ　ＯＦ　ＨＯＮＧＦＥＮＧ　ＬＡＫＥ，　ＣＨＩＮＡＡＮＮＵＡＬＬＡＭＩＮＡＴＩＯＮＳＩＮＴＨＥＳＥＤＩＭＥＮＴＳＯＦＨＯＮＧＦＥＮＧＬＡＫＥ，ＣＨＩＮＡ￥ＷｕＦｅｎｇｃｈａｎｇ；Ｗａ...  相似文献   

19.
Assessing the contribution of sediments from different sources is essential to understand erosive processes and formulate further soil conservation strategies to address environmental problems.In this study,we combined the source fingerprinting approach with geochemistry,including comparison of potential sources,and distribution pattern of major elements,to estimate the different land-use relative contributions to streambed sediment in the Luowugou catchment(13.5 km~2)located on the Heishui River,the first branch of the Jinsha River,China.A total of 57 samples from stream bank,cropland,grassland,forest land,and sediments were collected,and then,15 elements were analyzed foreach sample.The fingerprinting results demonstrated that the stream bank(62.4%)had the greatest relative contribution to the bed sediment yield,while cropland,grassland,and forest land contributed 18.6%,14.9%,and 4.1%to the bed sediments,respectively.In comparison to the fingerprinting method,even though the results upon geochemistry only provide a qualitative assessment,the ranking of sediment contributions based on geochemistry was consistent with the sediment fingerprinting ranking,that is,stream bankcroplandgrasslandforest land.Our findings suggest that the focal point for sediment control practices should be the stream bank rather than cropland in the region.Geochemistry can result in an important means in validating the fingerprinting results.  相似文献   

20.
以青藏高原西南部塔若错的34cm浅湖芯为研究对象,对其沉积物样品进行总有机碳、无机碳、总氮、微量元素、正构烷烃含量及碳氮比等多项指标的分析测定。采用过剩210 Pb和137 Cs计年法对该湖芯进行了定年和沉积速率研究,获得了近300年的连续湖泊沉积环境序列。在明确了各指标气候环境指示意义的前提下,综合对比分析湖芯中各项气候环境指标,并结合定年结果重建了塔若错湖区近300年来的气候环境变化。结果表明:塔若错湖区气候环境变化可分为3个明显阶段:早期为1705～1778年,该地区气候环境温暖湿润,湖区植被广泛发育;中期为1778～1860年,湖区处于小冰期末次阶段,气候环境寒冷而湿润,植被发育受阻;后期为1860年至今,为小冰期结束后偏暖干化时期。其中,后期又可分为3个亚阶段:1860～1924年,湖区气候环境稍暖且干旱,植被稍有发育;1924～1969年,湖区气候环境呈现偏冷干特点,植被发育暂缓;1969年至今,湖区气候回暖,环境干旱化有所缓解,植被开始逐渐发育。在气候冷暖变化上,该湖芯记录与古里雅冰芯记录和青海湖湖泊沉积记录都有较好的可对比性,只是在起讫年代上存在一些差异。  相似文献   

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