Early and late Holocene water-level fluctuations of Lake Annecy, France: sediment and pollen evidence and climatic implications

Early and late Holocene water-level changes in Lake Annecy, France, were reconstructed from a sediment sequence from Annecy. Two early Holocene successive rises in lake level at ca. 8900-8700 BP are recorded. Another increase in lake level, beginning at ca. 780 BP, is documented. The higher lake-level conditions in Lake Annecy during the 9th millennium BP, i.e. between the Preboreal oscillation and the 8200 yr event, appear to coincide with a more widespread cooling period which has been recorded in western Europe, in the Greenland ice-sheet and the North Atlantic ocean. The rise in lake level at ca. 780 BP can be related to the early Little Ice Age.     

A late Holocene record of land-use history,soil erosion,lake trophy and lake-level fluctuations at Bjäresjösjön (south Sweden)

Land-use history, soil erosion, lake trophy and lake-level fluctuations during the last 3000 years were reconstructed through a multidisciplinary palaeolimnological study (pollen, plant macrofossils, diatoms, physical and chemical analysis, magnetic measurements and radiometric methods) of a small eutrophic lake in southern Sweden (Bjäresjösjön, Scania). There are striking responses in diatom, chemical, sediment yield and magnetic records to land-use changes documented by pollen analysis or historical sources, and to lake-level changes identified from sedimentary changes. Our multidisciplinary approach assists interpretation of the processes controlling long-term changes and separation of the effects of different factors (land-use changes, lake-level fluctuations) on individual biostratigraphical records. Climate has controlled processes in the lake indirectly, through lake-level fluctuations, from the Late Bronze Age to the Viking Age (700 BC-AD 800). Since the Viking Age, land-use controlled most of the changes observed in the lake's development and soil erosion processes. Major changes in lake development occurred during the last 200 years, due to a drastic increase in soil erosion and water eutrophication during a period of agricultural modernization.     

Paleolimnological evidence of Holocene climatic changes in Lake Blanca, southern Uruguay

Paleolimnological data are presented on Holocene climatic changes in Lake Blanca, a small (0.6 km²), coastal fresh waterbody in southern Uruguay. Using a sediment core that extended to 7,300 year BP, analyses of pooid, panicoid and chloridoid phytoliths (Poaceae) allowed us to identify 16 Opal Phytoliths Association Zones (OPAZ). Both temperature and humidity indices were calculated from relative percentages of opal phytoliths and the climatic trends were inferred. During the early Holocene, prior to the first Holocene marine transgression (∼ ∼8,000–7,000 yr BP), cool-arid climatic conditions were inferred. After the first Holocene transgression, predominance of cool-humid conditions was registered until about 4,000 yr BP. A transition from cool-semiarid/arid to alternate warm-temperate and humid-very-humid conditions was detected for ∼∼4,000–1,000 yr BP. Increases in trophic state were observed because of such a climatic amelioration. After ∼ ∼1,000 yr BP, a shift from warm to temperate and cool temperatures was inferred. Such a cooling episode was assigned to a “LIA” which took place by the end of the 18th century and the beginning of the 19th century. A decrease in trophic state was observed during this climatic deterioration. After such a little ice age, present temperate humid conditions were established. The humidity indices calculated from relative percentages of opal phytoliths for the last ∼ ∼70 years were compared to annual rainfall data. Such a comparison showed that opal phytoliths are reliable indicators of humidity.     

青藏高原扎布耶盐湖晚全新世气候环境演化

青藏高原晚全新世气候变化具有不稳定性.在高原中部扎布耶盐湖边缘取得158.5cm沉积物,通过年代、孢粉、介形虫、粘土矿物、地球化学等多种环境指标,给出了湖区3.8cal. ka BP以来的气候环境演化.孢粉中草本花粉占绝对优势,其中又以蒿属为主,植被类型为水分条件稍好些的半荒漠化草原.粘土矿物主要是伊利石和绿泥石,伊/蒙混层矿物少量,说明湖区风化作用主要是物理风化.(Ca Mg)/CO2-3摩尔比值为0.22～0.96,小于1,CO2-3与Na 结合形成大量钠碳酸盐矿物如单斜钠钙石、氯碳钠镁石、水碱等.硼砂的出现说明湖区沉积环境稳定,但3.8～1.99 cal. ka BP硼等元素和碳酸盐含量变化幅度较大,湖区气候寒冷干燥,但冷暖干湿波动频繁.3.4～3.34 cal. ka BP介形虫壳大多破碎,说明此阶段水动力条件强,水体不稳定.1.99 cal. ka BP至今,气候相对温暖潮湿,波动较少.太阳辐射和西南季风强度的变化是造成气候变化的主要原因,冰川冻土对寒冷气候的放大作用也是湖区气候变化的一个重要原因.     

Holocene development of aquatic vegetation in shallow Lake Njargajavri,Finnish Lapland,with evidence of water-level fluctuations and drying

Holocene development of aquatic plant communities in subarctic Lake Njargajavri, Finnish Lapland, was studied using plant macrofossil analysis. Sediment lithology, grain size, and C/N ratios showed distinct lithological phases, indicating past water-level fluctuations. The colonization of limnophytes took place right after the formation of the lake (after ca. 11,500 cal. BP). The earliest plant macrofossil assemblages indicate nutrient-rich conditions and a warmer climate than at present. After this primary succession phase, aquatic vascular plants were replaced by aquatic bryophytes (before ca. 10,200 cal. BP). Together with lithological evidence, we interpret this as being related to the lowering water table. According to palynological, chronological, and sedimentological evidence, Njargajavri underwent a very shallow phase between ca. 10,000 and 9500 cal. BP and dried out for an unknown period of time between ca. 8000 and 5000 cal. BP. After the dry phase, the water level started to rise and sedimentation at the coring point began again. Despite re-establishment of the lacustrine habitat, late-Holocene plant macrofossil data show no marked recolonization of either vascular limnophytes or bryophytes. The reason for all limnophytes being presently absent from the lake remains speculative. The lack of nutrients and/or the cooling climate (especially shortening of the open-water season) during the latter part of the Holocene may explain why limnophytes failed to recolonize the lake.     

Late holocene environmental change in an upper Montane area of the snowy mountains,New South Wales

This study examines environmental change in the upper montane zone of the Australian Eastern Highlands during the late Holocene, by analysing vegetation, fire and erosion records contained within a small fen located in a frost hollow. Differences in environmental parameters across the prehistoric—historic boundary were particularly investigated in an attempt to characterise better the changes associated with the imposition of European land‐use practices. Decreases in arboreal pollen and an increased charcoal concentration near the base of the analysed sequence, interpreted to be about 1600 y BP until about 1300 y BP, are suggestive of reduced moisture availability. After this, a period of relative stability continued to the close of the prehistoric period. The arrival of Europeans in the region triggered changes in the sediment record, including an increase in the accumulation of sediment by an order of magnitude, and changes in the surrounding vegetation. Saturated isothermal remnant magnetism (SIRM) was found to be significantly higher in the historic period compared to the analysed prehistoric period, suggesting an alteration in the erosional processes within the catchment. The concentration of charcoal was comparable between the prehistoric and historic periods; however, the increased sedimentation rate of the historic period infers an increased accumulation of charcoal. Fire did not appear to be related to the vegetation changes evident in the historic period, perhaps due to the use of cool fires by the pastoralists.     

Palaeolimnological Development of Lake Njargajavri, Northern Finnish Lapland, in a Changing Holocene Climate and Environment

This study used palaeolimnological approaches to determine how Holocene climatic and environmental changes affected aquatic assemblages in a subarctic lake. Sediments of the small Lake Njargajavri, in northern Finnish Lapland above the present treeline, were studied using multi-proxy methods. The palaeolimnological development of the lake was assessed by analyses of chironomids, Cladocera and diatoms. The lake was formed in the early Holocene and was characterized by prominent erosion and leaching from poorly developed soils before the establishment of birch forests, resulting in a high pH and trophic state. The lake level started to lower as early as ca. 10,200 cal. BP. In the resulting shallow basin, rich in aquatic mosses, pH decreased and a diverse cladoceran and chironomid assemblage developed. It is likely that there was a slight rise in the water level ca. 8000 cal. BP. Later, during the mid-Holocene characterized by low effective moisture detected elsewhere in Fennoscandia, the lake probably completely dried out; this is manifest as a hiatus in the stratigraphy. The sediment record continues from ca. 5000 cal. BP onwards as the lake formed again due to increased effective moisture. The new lake was characterized by very low pH. The possible spread of pine to the catchment and the development of heath community may have contributed to the unusually steep (for northern Fennoscandia) decline in pH via change in soils, together with the natural decrease in leaching of base cations. Furthermore, the change in pH may have been driven by cooling climate, affecting the balance of dissolved inorganic carbon in the lake.     

The environmental significance of magnetic measurements of Late Pleistocene and Holocene sediments from the Grand Lac d'Annecy, eastern France

The results of a series of magnetic measurements on sediment samples are illustrated by means of examples selected from a more specialized parallel publication (Hu & Oldfield, submitted). They are interpreted in terms of magnetic components, notably, 'magnetite' of varying grain size/domain state, haematite, goethite and greigite. Wherever possible, some indication is given of changes in the relative importance of the various magnetic grain size and mineral phases through time. The main components of the magnetic assemblage are described for each of the main lithological units identified in the long core which is considered elsewhere in this volume. These assemblages are related to source areas and to depositional processes, especially in the pre-Holocene parts of the core. In the Holocene sediments, the magnetic properties cannot be interpreted solely in terms of shifts in detrital mineral sources. Evidence is presented for the presence of both biogenic magnetite and authigenic greigite. The most recent sediments point to renewed catchment erosion, probably as a result of human activity during historical times.     

Middle–Late Holocene Paleoclimate and Weathering History in the Norra Storfjället Mountains,Sweden: Deglacial Record and Soil Stratigraphy Applied to Neoglaciation in Lower Latitudes

The retreat record of the Stabre Glacier into the Norra Storfjället mountains, after separation from the massive Tärnaån Glacier at some undetermined time in the Atlantic Chron, is documented by recessional moraines in the foreland. While poorly constrained by radiometric dating, the age of the middle group of moraines averages out to less than 4000 cal ¹⁴C yr BP, the older moraine group probably of Late Atlantic age, with the youngest deposits of Little Ice Age (LIA). Soils/paleosols range from Entisols (youngest) and Inceptisols (middle group) to mature Spodosols (outer group), existing either as single‐story profiles or within pedostratigraphic columns, buried pedons either surfaced with weathered glacial or mass wasted deposits. Some profiles exhibit convoluted properties which could place them in the Cryosolic order. The physico‐mineral‐chemical properties of soils/paleosols in recessional deposits across this sequence provide weathering indices over the mid to Late Holocene in the Swedish sub‐Arctic climate. It is likely the middle group of deposits represents stillstand of the retreating glacier offset by climatic deterioration with the onset of Early Neoglacial climate which altered the glacial mass balance, at least until termination of the LIA. Correlation to other alpine areas in the middle and tropical latitudes with similar records is attempted and discussed. While the Stabre Glacier disappeared after the LIA, the nearby Tärna Glacier remains extant on the land surface, a presumed result of slight elevation differences between the two cirques which affects storm tracks and resultant variations in glacial mass balances.     

The relationship between glacial activity and sediment production: evidence from a 4450-year varve record of neoglacial sedimentation in Hector Lake, Alberta, Canada

A 4450-year sequence of varves, spanning the entire Neoglacialinterval, has been recovered from Hector Lake, Alberta. The varve record is compared to records of regional glacial history toevaluate therelationship between alpine glacial activity and sediment production. Glacial controls on sediment production vary with the timescale considered. Long-term variations in sedimentation rate, of centuries to millennial duration, reflect changes in ice extent of the same timescale. Superimposed on these long-term changes is decadal-scale variability that is complexly related to upvalley ice extent. Over the short term, high sedimentation rates may be associated with glacier maximum stands, or with periods of glacier advance or recession. Overthe last millennium at least, highest sedimentation rates appear to have been associated with transitional periods, preceding or post-dating maximum ice stands, rather than with times of maximum ice extent.     

Geomorphological evidence for the Late Holocene evolution and the Holocene lake level maximum of the Aral Sea

During the Holocene the Aral Sea underwent various transgressive and regressive phases of different magnitudes. However, previous work has not yet fully clarified the evolution and chronology of the individual phases. Research presented here throws light on the evolution of the Aral Sea during the past  2000 years. It includes field surveys, tachymetric and DGPS-derived altitude measurements, analysis of sediments from two areas of the northern and southern Aral Basin (Tastubek Bay and Karaumbet Bay), and their correlation with GIS-based lake area models. Geomorphological and sedimentological evidence from the study areas shows a transgression of the Aral Sea around 200 AD, ending at a lake level maximum of 54 to 55 m. After a medieval regression, the lake reached this level again between the late 16th and early 19th century AD. The digital elevation model SRTM-3 was used to estimate a lake size of 72,400 km² for the lake level maximum.Elevated palaeoshorelines, specifically at 72–73 m, are completely absent in the study areas. Local remains of escarpments at elevations of 66 m and 73 m are due to resistant Miocene caprock and are therefore not interpretable as shoreline features.     

Hydrologic and climatic implications of a multidisciplinary study of late Holocene sediment from Kenosee Lake, southeastern Saskatchewan, Canada

Sediment lithology and mineralogy, as well as ostracode, plant macrofossil and stable isotope stratigraphies of lake sediment cores, are used to reconstruct late Holocene hydrologic changes at Kenosee Lake, a relatively large, hyposaline lake in southeastern Saskatchewan. Chronological control is provided by AMS radiocarbon ages of upland and shoreline plant macrofossils. All indicators outline an early, low-water, saline phase of lake history (4100–3000 BP), when the basin was occupied by a series of small, interconnected, sulfate-rich brine pools, as opposed to the single, topographically-closed lake that exists today. A rapid rise in lake-level (3000–2300 BP) led to the establishment of carbonate-rich, hyposaline lake conditions like those today. Lithostratigraphic data and ostracode assemblages indicate peak salinities were attained early in this period of lake infilling, suggesting that the lake-level rise was initially driven by an influx of saline groundwater. Lake-level and water chemistry have remained relatively stable over the last 2000 years, compared to earlier events. Because of a lack of datable organic material in sediments deposited during the last 2000 years, the chronology of recent events is not well resolved. Plant macrofossil, lithostratigraphic and ostracode evidence suggests that lake draw-down, accompanied by slightly higher than present salinites, occurred sometime prior to 600 BP, followed by peak lake-level and freshwater conditions. This most recent high lake stand, indicative of a high water table on the surrounding upland, may also have led to the establishment of an extensive cover of Betula in the watershed, possibly in response to paludification. Ostracode assemblages indicate that peak freshwater conditions occurred within the last 100 years. Since historically documented lake-level fluctuations correlate with decadal scale climatic fluctuations in the meteorological record, and late-Holocene hydrologic dynamics correspond to well documented climatic excursions of the Neoglacial and Little Ice Age, Kenosee Lake dynamics offer insight into the susceptibility of the region's water resources to climate change.     

Late Pleistocene and Holocene history of Lake Terrasovoje,Amery Oasis,East Antarctica,and its climatic and environmental implications

A 5.52 m long sediment sequence was recovered from Lake Terrasovoje, Amery Oasis, East Antarctica, in order to reconstruct the regional environmental history. The basal sediments, which are dominated by glacial and glaciofluvial clastic sediments, attest to a Late Pleistocene deglaciation of the lake basin. These sediments are overlain by 2.70 m of laminated algal and microbial mats and a few interspersed moss layers. Radiocarbon dating, conducted on bulk organic carbon of 12 samples throughout the organic sequence, provides a reliable chronology since the onset of biogenic accumulation at c. 12,400 cal. year BP. Successful diatom colonization, however, was probably hampered by extensive ice and snow cover on the lake and restricted input of nutrients until 10,200 cal. year BP. A subsequent increase of nutrient supply culminated between 8600 and 8200 cal. year BP and is related to warm summer temperatures and reduced albedo in the catchment. Warm conditions lasted until 6700 cal. year BP, supporting the establishment of a diatom community. Colder temperatures from 6700 cal. year BP culminated in several periods between 6200 and 3700 cal. year BP, when high amounts of sulphur and low abundances of diatoms were deposited due to a perennial ice and snow cover on the lake. During the late Holocene, relatively warm conditions between 3200 and 2300 cal. year BP and between 1500 to 1000 cal. year BP, respectively, indicated by high accumulation of organic matter and reducing bottom water conditions, were interrupted and followed by colder periods.     

Late Pleistocene and Holocene lake fluctuations in the Sevier Lake basin,Utah, USA

Sevier Lake is the modern lake in the topographically closed Sevier Lake basin, and is fed primarily by the Sevier River. During the last 12 000 years, the Beaver River also was a major tributary to the lake. Lake Bonneville occupied the Sevier Desert until late in its regressive phase when it dropped to the Old River Bed threshold, which is the low point on the drainage divide between the Sevier Lake basin and the Great Salt Lake basin. Lake Gunnison, a shallow freshwater lake at 1390 m in the Sevier Desert, overflowed continuously from about 12 000 to 10 000 yr B.P., into the saline lake in the Great Salt Lake basin, which continued to contract. This contrast in hydrologic histories between the two basins may have been caused by a northward shift of monsoon circulation into the Sevier Lake basin, but not as far north as the Great Salt Lake basin. Increased summer precipitation and cloudiness could have kept the Sevier Lake basin relatively wet.By shortly after 10 000 yr B.P. Lake Gunnison had stopped overflowing and the Sevier and Beaver Rivers had begun depositing fine-grained alluvium across the lake bed. Sevier Lake remained at an altitude below 1381 m during the early and middle Holocene. Between 3000 and 2000 yr B.P. the lake expanded slightly to an altitude of about 1382.3 m. A second expansion, probably in the last 500 years, culminated at about 1379.8 m. In the mid 1800s the lake had a surface altitude of 1379.5 m. Sevier Lake was essentially dry (1376 m) from 1880 until 1982. In 1984–1985 the lake expanded to a 20th-century high of 1378.9 m in response to abnormally high snow-melt runoff in the Sevier River. The late Holocene high stands of Sevier Lake were most likely related to increased precipitation derived from westerly air masses.This is the first of a series of papers to be published by this journal that was presented in the paleolimnology sessions organized by R. B. Davis and H. Löffler for the XIIth Congress of the International Union for Quaternary Research (INQUA), which took place in Ottawa, Canada in August 1987. Drs. Davis and Löffler are serving as guest editors of this series.     

Holocene sedimentation in Lake Winnipeg, Manitoba, Canada: implications of compositional and textural variations

Two seismic facies were recognized in the sedimentary sequence overlying acoustic basement in Lake Winnipeg. The upper facies, which overlies a regional unconformity, is termed the Lake Winnipeg Sequence. Based on the seismostratigraphy, lithostratigraphy, and radiocarbon dates of approximately 4000 and 7000 yr BP from material collected directly over the unconformity in the southern and northern parts of the lake, respectively, this facies has been interpreted as representing Holocene sedimentation. Results of compositional and textural analyses of the Holocene sediment (Winnipeg sediment) from thirteen long (>2 m) cores indicate a transgressional sequence throughout the basin. In the South Basin, the generally fining upward sequence is characterized at the base by silt-sized detrital carbonate minerals, quartz and feldspar which decrease in concentration upward. In this basin, the high carbonate content and V/Al and Zn/Al ratios are indicative of a Paleozoic and Cretaceous provenance for sediment derived from glacial deposits through shoreline erosion and fluvial transport, via the Red River. Sedimentation in the central part of the lake and the North Basin is attributed to shoreline erosion of sand and gravel beaches. Consequently, the texture of these sediments is generally coarser than in the South Basin, and the composition primarily reflects a Paleozoic and Precambrian provenance. The basin-wide decrease in Ca, total carbonate minerals, dolomite and calcite concentrations upward in the cores is reflected by a decrease in the detrital carbonate component in all but the most northern cores. Other basin-wide trends show an upward increase in organic content in all cores. An increase in grain size near the top of most cores suggests a major, basin-wide change in sedimentation within the last, approximately 900 years in the South Basin.     

中国兴凯湖北岸平原晚全新世花粉记录及泥炭沼泽形成

通过兴凯湖北岸平原泥炭剖面高分辩率花粉分析研究，对晚全新世花粉划分4个组合带。XKH-4组合时期(1857～1746aB．P．)为沼泽发育前期，这一时期花粉浓度小，陆生草本植物占优势，气候干冷。XKH-3组合时期(1746～1287aB．P．)为沼泽发育早期，这一时期花粉浓度较大，且水生植物花粉含量为剖面最高，喜温落叶阔叶植物大发展时期，气候温和湿润。XKH-2组合时期(1287～602aB．P．)为沼泽发育中期，这一时期花粉浓度最小，但以陆生草本植物为主，木本植物为辅，水生植物急剧减少，针叶植物出现两次高峰，气候向冷干方向发展。XKH-1组合时期(602aB．P．至今)为沼泽发育盛期，这一时期花粉浓度最大，陆生草本植物大发展时期，气候波动较大。     

Magnetic susceptibility in sediment records of Lake Ådran,eastern Sweden: correlation among cores and interpretation

Magnetic susceptibility was used to test the representativity of the lithostratigraphy of a master sediment sequence from Lake Ådran, eastern Sweden. Five further sediment cores from the same lake were correlated and compared with the master sequence using magnetic susceptibility records. Mineral magnetic correlations are generally based on matching prominent susceptibility features but may be significantly improved by using slot sequence analyses. The result of these analyses show that the sediment in the Lake Ådran master sequence can be considered representative for the basin. The variations in the magnetic susceptibility in relation to pollen and diatom analyses also seem to reflect water level changes and shore displacement in the Baltic between 9900 ¹⁴C years B.P. and the isolation at 5900 ¹⁴C years B.P. The first emergence of scattered non-vegetated islands is characterised by high susceptibility values. Along with a continuous water lowering and the development of the vegetation during the Ancylus fresh water stage, susceptibility values gradually decrease. A rapid phase of the Ancylus regression between 9200 and 9000 ¹⁴C years B.P. is seen as an increase in magnetic susceptibility. During the following Baltic brackish water stage, the Litorina stage, susceptibility values are at their lowest, followed by higher values at the isolation from the Baltic with a maximum around 5000 ¹⁴C years B.P.Shore displacement between 9900 and 5900 ¹⁴C years B.P. is discussed based on the magnetic susceptibility measurements and their relationship to the pollen and diatom analyses.     

Evolution of clay mineral assemblages and organic matter in the late glacial-Holocene sedimentary infill of Lake Annecy, (northwestern Alps): paleoenvironmental implications

The basin fill of Lake Annecy was investigated from a 44 m core which reached down to glacial sediments of the last glaciation (called Würm in the alpine areas). We analyzed three main parameters: sediment texture (optical microscopy and laser microgranulometry), clay mineral assemblages (CMA by XRD), and organic matter (OM by Rock-Eval pyrolysis). Settling of suspended load, under variable hydrodynamic conditions is the main depositional process. Both CMA and OM provenances can be recognized for the different sedimentary and igneous-metamorphic formations (Carboniferous to Quaternary, and older crystalline basement) and corresponding areas, in the surrounding region of Lake Annecy. Oligocene-Miocene molasses, Early Cretaceous marls, and Early-Middle Jurassic marls and shales are the main sedimentary sources. Two distinct processes were operating: destruction of glacial sediments (till sensu largo) and reworking, or direct erosion and run-off from ice-free catchment areas. Clay minerals related to pedogenesis, and non-reworked terrestrial and lacustrine OM, were progessively added to these primary sources during the Late Würmian/Holocene transition to warmer climatic conditions. Rapid modifications of CMA and OM sources during the earlier phase of sedimentary infilling (Unit 2) suggest that valley glaciers connected to the lake basin almost completely disappeared within a few centuries.     

Geomorphic and sedimentologic evidence for the separation of Lake Superior from Lake Michigan and Huron

A common break was recognized in four Lake Superior strandplain sequences using geomorphic and sedimentologic characteristics. Strandplains were divided into lakeward and landward sets of beach ridges using aerial photographs and topographic surveys to identify similar surficial features and core data to identify similar subsurface features. Cross-strandplain, elevation-trend changes from a lowering towards the lake in the landward set of beach ridges to a rise or reduction of slope towards the lake in the lakeward set of beach ridges indicates that the break is associated with an outlet change for Lake Superior. Correlation of this break between study sites and age model results for the strandplain sequences suggest that the outlet change occurred sometime after about 2,400 calendar years ago (after the Algoma phase). Age model results from one site (Grand Traverse Bay) suggest an alternate age closer to about 1,200 calendar years ago but age models need to be investigated further. The landward part of the strandplain was deposited when water levels were common in all three upper Great Lakes basins (Superior, Huron, and Michigan) and drained through the Port Huron/Sarnia outlet. The lakeward part was deposited after the Sault outlet started to help regulate water levels in the Lake Superior basin. The landward beach ridges are commonly better defined and continuous across the embayments, more numerous, larger in relief, wider, have greater vegetation density, and intervening swales contain more standing water and peat than the lakeward set. Changes in drainage patterns, foreshore sediment thickness and grain size help in identifying the break between sets in the strandplain sequences. Investigation of these breaks may help identify possible gaps in the record or missing ridges in strandplain sequences that may not be apparent when viewing age distributions and may justify the need for multiple age and glacial isostatic adjustment models. This is the third in a series of ten papers published in this special issue of Journal of Paleolimnology. These papers were presented at the 47th Annual Meeting of the International Association for Great Lakes Research (2004), held at the University of Waterloo, Waterloo, Ontario, Canada. P.F. Karrow and C.F.M. Lewis were guest editors of this special issue. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.