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1.
In the Ebinur region of Western Dzungaria, strong wind flows from Dzungarian Gate predetermine the widespread development of deflation processes. As a result of human-induced desiccation of Lake Ebinur, a new source of the loose material—the dry lakebed—has formed, which has intensified dust storms in this region. Annual dynamics of the frequency and intensity of dust storms and the amount and chemical composition of salts in the eolian material deposited in the area have been studied. The frequency of dust storms and the intensity of dust and salt deposition regularly decrease with an increase in the distance from the dry lake bottom (playa). The amount of dust deposition ranges from 600 (near the lake) to 70 (100–200 km from the lake) g/m2/a. The amount of salts precipitating with dust is mainly from 14 to 27 g/m2/a; the maximum registered amount of salt deposition is 77 g/m2/a. As shown in our study, the farther from the lake, the higher the portion of sulfate and calcium and the smaller the portion of chloride and sodium ions in the composition of salts. 相似文献
2.
Two short sediment cores were recovered from sub-basins of Lake Qinghai, China and were analyzed for concentrations of Pb
and 16 other elements to determine historic, regional atmospheric Pb deposition on the Tibetan Plateau. Core chronologies,
dating back to the eighteenth century, were established using activities of 210Pb and 137Cs. The 17 elements were divided into three principal components. Variations in concentrations of PC1 elements (Al, Cr, Cu,
Fe, K, Mn, Ni, and Ti) demonstrate different patterns between the two cores, and are attributed to different sediment sources
in the two sub-basins. PC2 elements (Ba, Ca, Na, and Sr) may be associated with the degree of catchment weathering and/or
water chemistry. Four elements (Pb, Zn, P, and Co) are related to both PC1 and PC2, and reflect a mixture of natural and anthropogenic
sources. The PC3 element is Mg in the north sub-basin, and is perhaps related to aragonite precipitation and/or increased
farming. Elevated Pb concentrations in uppermost sediments of both cores signify a recent regional/global increase in anthropogenic
Pb release into the environment. After subtracting lithogenic Pb, derived from rock weathering and/or dust and normalized
to the background immobile element Ti, results suggest that excess, anthropogenic Pb is transferred to the lake and its sediments
predominantly via the atmosphere. This anthropogenic atmospheric Pb is comparable in magnitude and displays similar variation
patterns in the two cores, reflecting regional atmospheric deposition and local erosion. The average anthropogenic Pb deposition
rate in Lake Qinghai since the 1960s has been ~12.2 ± 3.5 mg/m2/a, comparable with atmospheric Pb fluxes reported for sites elsewhere in the northern hemisphere. 相似文献
3.
Georg Schettler Qiang Liu Jens Mingram Jörg F. W. Negendank 《Journal of Paleolimnology》2006,35(2):239-270
The varved sediments of the dimictic Lake Sihailongwan (Long Gang mountain area, Jilin Province, Northeast China) represent
a palaeoclimatic archive which documents the local precipitation frequency during the summer monsoon, and variations in the
aeolian flux of dust with their remote sources in the arid and semi-arid regions of inner Asia. Based on a detailed discussion
of sediment genesis in Lake SHL, dust flux rates and palaeohydrological conditions were reconstructed on a decadal scale over
the past 220 years. The aeolian influx by dry and wet deposition was quantified and characterised in its chemical composition.
Photosynthetic production in the lake is positively correlated with the inflow of nutrient-rich groundwater. The groundwater
discharge largely reflects the strength of the summer monsoon. Net accumulation rates for biogenic silica were determined
for annually laminated sediments from the centre of the U-shaped lake basin based on sediment data. In a Si-balance model
of the modern lake, the depositional flux of biogenic silica could be independently quantified on the base of hydrochemical
monitoring data. Comparison of the both estimates allowed to asses the focussing of the particle flux in the lake. Though
water retention in Lake SHL is rather high (ca. 30 years), changes in the hydrological conditions are sensitively recorded
in the sediments because (i) nutrient-rich groundwater discharges into the productive zone of the lake, (ii) a substantial
proportion of the total dissolved Si-inventory of the mixed lake (ca. 30%) is annually consumed by diatom growth, and (3)
sediment accumulation is substantially focussed towards the flat bottom of the lake basin. The bulk siliciclastic sediment
fraction (ca. 75 wt.%) largely originates from influx of dust of remote provenance. In sediment thin-sections, the dry-deposited
dust fraction is microscopically identifiable as seasonal silt layer. Aeolian input by wet-deposition shows a distinctly higher
variability than the influx of dust by dry-deposition. As diatom production, wet-deposition of dust is positively correlated
with the rainfall during the summer monsoon. The inferred positive correlation between rainfall and dust flux during the summer
monsoon implies that dust deposition is determined by the out-wash efficiency of mineral particles for a permanent high atmospheric
dust concentration over Northeast China in the last 220 years. 相似文献
4.
Revital Bookman Charles T. Driscoll Steven W. Effler Daniel R. Engstrom 《Journal of Paleolimnology》2010,43(3):449-462
Geochemical analysis of 210Pb-dated sediment cores from Otisco Lake (New York) combined with analysis of recent land cover change in the watershed revealed
the history of land use change, lake management, and industrial pollution since European settlement in the northeastern US.
Clearance of forestland for agriculture characterized the early settlement era that was marked in the Otisco Lake sediments
by a decline in organic carbon (OC) and OC:N ratios, which indicate a change in the sources of organic matter to the lake.
Agricultural land use reached its greatest areal extent in the Otisco watershed around 1900, followed by field abandonment
and reforestation over the last century. In the 1920s sediment accumulation rates began to increase coincident with residential
development along the lake shore. Nitrogen and organic carbon, which are transported from the watershed, show increased fluxes
to the lake in response to this change. Deposition of inorganic carbon increased markedly over a short period from the 1940s
to the 1980s, which is consistent with enhanced mobilization of watershed calcium by increased acidic deposition, followed
by alkalinization of the lake waters and calcite precipitation. An increase in copper content in the sediments reflects application,
since 1942, of the algicide copper sulfate to the lake waters to control algal blooms. This CuSO4 marker confirmed the accuracy of the 210Pb chronology. Atmospheric mercury (Hg) fluxes to the lake were affected by increased sediment transport from the watershed.
The maximum Hg peak in the sediment record, however, was dated to the early 1970s and coincides with maximum Hg emissions
to the atmosphere in the Great Lakes region. 相似文献
5.
The suitability of a south Pennine reservoir as an archive of recent industrial pollution (Pb deposition) and vegetation change was assessed by comparing the sediment record of Pb and pollen with a local blanket peat profile, and the modelled regional SO2 deposition since 1840. The pollen-based record of vegetation change from the reservoir sediments was obscured by high inputs of eroded peat from the surrounding catchment. Total fluxes of Pb from the catchment into the reservoir varied between 0.05 and 2.67 kg km−2 year−1 during a 7 year period of increased peat erosion (1976–1984). The presence of concentration peaks in the Pb profile of the blanket peat may have been caused by changes in sulphide or redox chemistry within the peat profile. Large variations in influxes of Pb to the reservoir occurred during periods of increased peat erosion, suggesting the record of aerial pollution deposition has been obscured by terrestrial inputs. Extensive areas of blanket peat in the south Pennines have been subject to denudation, suggesting reservoirs in the region and other areas of high erosion and sediment flux are unsuitable for producing accurate records of the aerial deposition of pollen rain and Pb pollution. The ecological implications of highly variable fluxes of heavy metal contaminants from extensively eroded blanket bogs to ecosystems downstream are poorly understood. 相似文献
6.
基于SCS和USLE的程海总磷总氮参照状态推断 总被引：2，自引：0，他引：2
将流域入湖的氮磷负荷分为点源和非点源两部分,基于SCS模型和USLE模型,分别计算流域入湖的溶解态和颗粒态非点源负荷,根据工业、城镇生活及规模养殖废水排放,计算了流域入湖的点源负荷。通过计算的入湖负荷和现有的湖泊氮磷浓度数据,建立了湖泊氮磷质量守恒模型。根据计算的逐年入湖氮磷负荷和建立的湖泊氮磷质量守恒模型,逆推逐年的湖泊氮磷浓度,确定湖泊氮磷参照状态。应用建立的模型推断程海的TP、TN参照状态分别为0.014 mg/L和0.247 mg/L。构建的湖泊氮磷参照状态推断模型,所需资料少,概念清晰,在资料缺乏的其他湖泊流域具有推广应用价值。 相似文献
7.
Mary Beth Day David A. Hodell Mark Brenner Jason H. Curtis George D. Kamenov Thomas P. Guilderson Larry C. Peterson William F. Kenney Alan L. Kolata 《Journal of Paleolimnology》2011,45(1):85-99
Tonle Sap Lake, Cambodia, possesses one of the most productive inland fisheries in the world and is a vital natural resource
for the country. The lake is connected to the Mekong River via the Tonle Sap River. Flow in the Tonle Sap River reverses seasonally,
with water exiting the lake in the dry season and entering the lake during the summer monsoon. This flood pulse drives the
lake’s biological productivity. We used Sr, Nd, and Pb isotopes and elemental concentrations in lake sediment cores to track
changes in the provenance of deposits in Tonle Sap Lake. We sought to determine when the lake first began to receive water
and sediment input via the Mekong River, which initiated flood pulse processes. The transition from a non-pulsing lake to
the Mekong-connected system is marked by shifts to values of 87Sr/86Sr, εNd, and 207Pb/204Pb that are characteristic of Mekong River sediments. In addition, magnetic susceptibility increased and sediment elemental
composition changed. Elemental (P) measures point to enhanced phosphorus loading and C/N and isotope ratios of bulk organic
matter indicate a shift to greater relative contribution of organic material from aquatic versus terrestrial environments,
coinciding with the initiation of flood pulse processes. On the basis of radiocarbon dating in two cores, we estimate the
initiation of the annual flood pulse occurred between ~4,450 and 3,910 cal year BP. 相似文献
8.
9.
10.
Dag Hongve 《Journal of Paleolimnology》2003,30(1):75-93
Cores of recent sediments were sampled along a depth gradient in a 23 m deep kettle lake with stagnant deep waters containing exceptionally high concentrations of dissolved iron and manganese. Sediment cores were taken on two occasions, in 1978 and 1997, before and after an incidence of full circulation. The aims of this study are to see how oxic and anoxic conditions in the water column influence stratigraphy and sediment focusing and, to compare cores from 1979 and 1998 to see how measured element fluxes and external events are reflected in the chemical stratigraphy. Element analyses show characteristic stratigraphic patterns that depend on the ability to undergo redox transformations, sorptive properties and chemical equilibria in the anoxic deep waters and porewaters. In sediments from the oxic part of the lake Al, Cr, Co, Ni, Zn Cu, Cd, and Pb were well correlated. Positive correlations are seen between elements associated with primary production and sulphur. In the anoxic part of the lake most metals were positively correlated with carbonate. Phosphorus correlated positively with iron in sediments from oxic waters and negatively with manganese and iron deep-water sediments. Porewater analyses indicate that recycling from the deep-water sediments was negligible. The stratigraphy of lead agrees with the historic variation in atmospheric input and is used as a chronological marker. Assessed deposition rates agree with measurements in sediment traps. Most elements more than double their rates of deposition towards the deepest point of the lake, while sulphur, manganese and carbonate had maxima around the depth of the redoxcline in the water. Variations in the external loading and variable redox conditions in the deep waters explain variations in the chemical composition of recent sediments. 相似文献
11.
Sources and chronologies of metal contamination were studied in sediment cores of three lakes of the Rouyn-Noranda mining
area (Québec, Canada) affected by atmospheric deposition of anthropogenic contaminants. One of the three lakes also received
acid mine drainage. The sediments were dated using 210Pb and 137Cs and analysed for stable Pb isotope ratios and for total concentrations of 15 elements (Ag, Al, Au, Ca, Cu, Cd, Fe, Hg,
Mn, Ni, P, Pb, S, Ti, Zn). Stable lead isotopic signatures helped to determine the quantitative contributions of different
industrial Pb sources to our sampling sites. This source apportionment showed the dominant influence of the Rouyn-Noranda
copper smelter in airborne Pb emissions for the decades following 1926, when industrialization began in the region. The smelter
source had a low ratio of 206Pb/207Pb ranging between 0.90 and 1.05, as typical of the Abitibi Archean sulphides. The relationships between element (metal) sedimentary
fluxes and anthropogenic Pb fluxes allowed us to infer the origin of the anthropogenic source. These relationships strongly
suggest that the copper smelter was (and may still be) an atmospheric source of Cd, Cu, Pb, Zn, Ag and Hg to the surrounding
lakes. Our study indicates that the efforts made by the Rouyn-Noranda copper smelter to reduce airborne emissions of metals
have been translated in reduced atmospheric metal loadings to the surrounding lakes. 相似文献
12.
Land degradation resulting from land-use changes and soil erosion has been a serious environmental problem in Ethiopia. This study addressed the effects of land use and slope position on soil physical and chemical properties in the Gelana sub-watershed, Northern highlands of Ethiopia. A total of 63 soil samples were collected and analyzed using a two-way ANOVA. Results showed that clay, soil pH, soil organic matter, total nitrogen, cation exchange capacity, and exchangeable base contents of the cultivated land were significantly (p < 0.001) lower than those of the forest land, while soil bulk density, available phosphorous, and percentage base saturation were higher for cultivated land than forest land. In general, soil fertility declines as land use changes from forest to grazing and cultivated lands. Sand, clay, bulk density, soil pH, organic matter, total nitrogen, carbon:nitrogen ratio, available phosphorous, cation exchange capacity, exchangeable cations, and percentage base saturation showed significant variation due to slope position differences. Therefore, the study reinforces the need for integrated watershed management for sustainable agricultural production in the study area. 相似文献
13.
Reservoir sediments are rarely used as environmental archives because of the potential for sediment disturbance by fluctuating
water levels. However, rapid rates of sedimentation, proximity to urban centres and often the existence of management records,
may make them potentially important resources for reconstructing recent, anthropogenically-derived environmental change. This
project assesses the potential of reservoir sedimentary records for reconstructing past atmospheric and drainage basin fluxes
of heavy metals (manganese, iron, nickel, copper, zinc and lead) in the southern Pennines, UK. Five reservoirs were selected
on the basis of management history and drainage basin characteristics. Multi-parameter analysis showed sediments to be replicable
across the ȁ8accumulating zone’ with reasonably consistent rates of sedimentation. Water level fluctuations were not found
to detrimentally affect sediment records in the deepwater area of the reservoirs. In fact, spheroidal carbonaceous particle
(SCP) profiles show trends in inputs that closely reflect major changes in industrialisation, indicating the reservoir sediments
to be excellent records of particulate inputs. Only lead (Pb) and zinc (Zn) were significantly enriched in the reservoir sediment
in comparison to background levels. Manganese (Mn), iron (Fe) and to a limited degree, copper (Cu), appeared to be affected
by post-deposition mobility. Preliminary calculations of Pb fluxes indicate that over 80% of the current Pb input to the reservoirs
is from Pb deposited onto drainage basin soils in the past, rather than from direct atmospheric deposition or natural background
inputs. In Howden reservoir, for example, the total Pb flux to deepwater sediment cores in 2000 was 119 mg m−2 a−1. Of this, an estimated 99 mg m−2 a−1 was from anthropogenically-derived Pb, initially deposited onto drainage basin soils and subsequently entering the reservoir
via erosion and leaching processes. There is, therefore, no indication that the flux of Pb to the aquatic system is declining
in response to reductions in Pb deposition. The ecotoxicological effects of the high and continuing Pb flux to these reservoirs,
despite recent decreases in atmospheric deposition, is an area requiring further investigation. 相似文献
14.
Ulla Kokfelt Nina Reuss Eric Struyf Mats Sonesson Mats Rundgren G?ran Skog Peter Rosén Dan Hammarlund 《Journal of Paleolimnology》2010,44(1):327-342
Permafrost in peatlands of subarctic Sweden is presently thawing at accelerated rates, which raises questions about the destiny
of stored carbon and nutrients and impacts on adjacent freshwater ecosystems. In this study we use peat and lake sediment
records from the Stordalen palsa mire in northern Sweden to address the late Holocene (5,000 cal BP-present) development of
the mire as well as related changes in carbon and nutrient cycling. Formation, sediment accumulation and biogeochemistry of
two studied lakes are suggested to be largely controlled by the development of the mire and its permafrost dynamics. Peat
inception took place at ca. 4,700 cal BP as a result of terrestrialisation. Onset of organic sedimentation in the adjacent
lakes occurred at ca. 3,400 and 2,650 cal BP in response to mire expansion and permafrost aggradation, respectively. Mire
erosion, possibly due to permafrost decay, led to re-deposition of peat into one of the lakes after ca. 2,100 cal BP, and
stimulated primary productivity in the other lake at ca. 1,900–1,800 cal BP. Carbonate precipitation appears to have been
suppressed when acidic poor fen and bog (palsa) communities dominated the catchment mire, and permafrost-induced changes in
hydrology may further have affected the inflow of alkaline water from the catchment. Elevated contents of biogenic silica
and diatom pigments in lake sediments during periods of poor fen and bog expansion further indicate that terrestrial vegetation
influenced the amount of nutrients entering the lake. Increased productivity in the lake likely caused bottom-water anoxia
in the downstream lake and led to recycling of sediment phosphorous, bringing the lake into a state of self-sustained eutrophication
during two centuries preceding the onset of twentieth century permafrost thaw. Our results give insight into nutrient and
permafrost dynamics in a subarctic wetland and imply that continued permafrost decay and related vegetation changes towards
minerotrophy may increase carbon and nutrient storage of mire deposits and reduce nutrient fluxes in runoff. Rapid permafrost
degradation may on the other hand lead to widespread mire erosion and to relatively short periods of significantly increased
nutrient loading in adjacent lakes. 相似文献
15.
Assessment of nutrient sources and paleoproductivity during the past century in Longgan Lake,middle reaches of the Yangtze River,China 总被引：3，自引：0，他引：3
Total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) were determined in combination with stable isotope
ratios of carbon and nitrogen (δ13COrg, δ15N) in a 63 cm sediment core from Longgan Lake, located in the middle reaches of the Yangtze River, China. These geochemical
and isotopic records provide a continuous history of lake productivity and trophic state of Longgan Lake since 1890. Variations
of δ13COrg, TOC, TN and TP indicate that primary productivity of Longgan Lake increased continuously during the last century and that
the trophic state of the lake shifted from oligotrophic to mestrotrophic conditions accordingly. Anthropogenic sources of
organic carbon (OC), nitrogen (N) and phosphorus (P) were distinguished from their natural background in the sediments using
mass accumulation rates. Element mass accumulation rates suggested increased human activities in the lake’s catchment since
1950s, were especially the utilization of artificial fertilizers amplified the anthropogenic input of N and P into the lake.
In the course of the improved availability of dissolved nutrients also primary productivity of Longgan Lake increased, resulting
in an increase of the Suess-effect corrected organic carbon isotope ratios. δ15N of bulk sediments show a marked shift towards lower values around 1950 that has been attributed to the input of nitrogen
from chemical fertilizers characterized by relatively depleted isotopic signatures into the lake. 相似文献
16.
Lake-Sediment Evidence for Local and Remote Sources of Atmospherically Deposited Pollutants on Svalbard 总被引：4，自引：4，他引：4
Twenty-one lakes along the west coast of Svalbard were cored between 28 July and 14 August 1995. Five cores were 210Pb dated and analysed for spheroidal carbonaceous particles (SCPs), indicators of deposition from fossil-fuel combustion sources, and trace metals. Surface and pre-industrial levels of five cores were analysed for 10 polychlorinated biphenyl (PCB) isomers and 16 polycyclic aromatic hydrocarbon (PAH) compounds, whilst all 21 surface sediments were analysed for SCPs. Temporal and spatial trends in the atmospheric deposition of pollutants were identified. Whilst temporal patterns of deposited pollutants may have been truncated due to concentrations falling below the limits of detection, spatial patterns showed elevated levels of SCP, PAH, PCB, and possibly Pb within 60–70 km of Isfjord. Tenndammen (U), the closest site to Longyearbyen, showed the highest levels of contamination for all pollutants. Differences in the deposition patterns of PAH and PCB are thought to be due to local sources of PAH from coal combustion whilst PCB sources are remote. It is concluded that the impact from atmospheric deposition on Svalbard is due to a combination of spatially limited local sources superimposed on a broad-scale, long-range pattern. 相似文献
17.
Increased human activities since discovery of gold in northern California have changed the structure and function of many ecosystems. To reconstruct the changes in watershed environmental conditions, sediment cores were collected from three montane marshes in northern Sierra Nevada, CA. Pollen analysis was conducted, and water content, bulk density, ash, carbon, nitrogen, phosphorus, major cations, and lead concentrations of sediments were determined. Cores were dated by the 210Pb method. Pollen analyses showed changes in plant communities in this region due to severe logging in the late-1800s and moderate logging in the 1900s. The local changes were more clearly recorded in small marsh pollen profiles than regional changes. The water milfoil (Myriophyllum spicatum L.) introduction into Tahoe Basin was inferred from the pollen record and 210Pb dating. Road construction and maintenance activities were recorded in physical and chemical characteristics, such as increases in sodium, calcium, and magnesium concentrations. Pollen and physical and chemical records also documented the time line of the expansion of dry meadow, and the decrease of pine forest in one of the watersheds. This study showed that sediments in small marshes were especially useful to reconstruct local disturbance by human activities. 相似文献
18.
I. A. Belozertseva I. B. Vorobyeva N. V. Vlasova M. S. Yanchuk D. N. Lopatina 《Geography and Natural Resources》2017,38(1):68-77
It is found that pollution of the territory from local sources of the zone of atmospheric influence spreads over several tens of kilometers along the prevailing wind direction, and in the central zone it is replaced by regional pollution. Snow pollution in the water area of Lake Baikal was recorded near coastal settlements and in the mouth of the Selenga river. It is established that the southern hollow of Baikal holds the lead in the input of NO2, NO3, NH4, PO4, F, Al, Na, Ba, Mo, Mn, Pb, Cu, Zn, Sr, Hg and oil products to the lake’s water area in spite of the fact that it is twice as small as the northern hollow. The northern hollow receives much larger amounts of SO4, H2CO3, Cl, Ca, Mg and K than the northern hollow, and much larger amounts of Be, V, Cr and Co than the middle hollow, which is associated with the operation of coastal enterprises, boilers, thermoelectric plants, stove heating, automobile exhaust emissions, and with the natural transport of dust in snow-deficient areas of the middle hollow. It is determined that that last five years saw a slight increase in regional pollution for separate components. It is shown that in the late 1990s and in the early 2000s, pollution decreased twice, which was due to the setback in industrial production. 相似文献
19.
P. Anadón R. Utrilla A. Vázquez M. Martín-Rubio J. Rodriguez-Lázaro F. Robles 《Journal of Paleolimnology》2008,39(3):399-419
Stable isotopes and trace-element content of calcite ostracod valves and aragonite mollusc shells from the Pliocene lacustrine
succession of Villarroya allow depicting the geochemical record of environmental changes and to compare our data to the paleoenvironmental
reconstruction obtained from other proxies. The lower sequences (A and B) are characterized by relatively high isotopic and
Me/Ca values in the biogenic carbonates. The recorded large variations of δ18O in these carbonates mainly reflect variations in the δ18Ow due to precipitation–evaporation processes and, to a lesser extent, variations in temperature of calcification. The δ13C data inform about changes in DIC although they are probably biased by the vital effects of the studied taxa. Minor and trace
element contents in ostracod (Mg/Ca, Sr/Ca) and mollusc shells (Sr/Ca) are mainly linked to the Me/Ca of the lake water (Me/Caw), and to a lesser extent to temperature and to uptake kinetic effects. Several possible mechanisms may make the Me/Caw to vary: long periods of Ca-carbonate (calcite, aragonite) deposition after charophyte development, and different inputs
for Ca and Mg to the lake due to changes in drainage area configurations through time, including the changes in saline inputs
(Na-Cl type) to the lake. The stable isotopes and the calculated Sr/Caw and Mg/Caw from sequence C display lower values than those from sequences A and B. The isotopic values from biogenic carbonates of unit
C indicate isotopically diluted waters in a hydrologically open lacustrine environment. Distinct δ13C and δ18O plots for molluscs from unit C reflect the different biotopes and metabolism type. For several intervals of the Villarroya
succession there is no direct relationships among: (i) salinity changes inferred from invertebrate paleoecology, (ii) paleoenvironmental
slices based on isotopic signatures and Me/Caw calculations (from biogenic carbonate geochemistry) and (iii) climate in the hinterland deduced from pollen data. Lakes where
geochemical behaviour is constrained by sporadic saline inputs and/or relative depletion in Ca due to long periods of Ca-carbonate
precipitation or biomineralization, like the Pliocene Villarroya lake was, do not show clear correlation patterns between
geochemical signals and climate proxies. In these lakes only major environmental trends display unambiguous geochemical signatures,
and only some main shifts in the geochemical signature profiles may be correlated with significant global and/or regional
environmental changes that have been reported from other paleoenvironmental records.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
