scholarly journals Radiocarbon Dating of Lake Sediment from Two Karst Lakes in Yugoslavia

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 495-502 ◽  
Author(s):  
Dušan Srdoč ◽  
Bogomil Obelić ◽  
Nada Horvatinčić ◽  
Ines Krajcar-Bronić ◽  
Elena Marčenko ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Sedimentation Rate ◽  
National Park ◽  
Radiocarbon Dating ◽  
Sediment Cores ◽  
Karst Area ◽  
Seismic Profiles ◽  
Karst Lakes ◽  
Isotopic Studies

Samples of sediment cores from two lakes in the karst area of northwest Yugoslavia were analyzed. Both Lakes Kozjak and Prošće are in the Plitvice National Park, Central Croatia. 14C dating, sedimentologic, seismic, and isotopic studies, and distribution of diatoms are presented.14C dating of lake marl revealed a uniforn sedimentation rate in Lake Prošće as opposed to Lake Kozjak. Both lake sediments belong to the Holocene period. 14C dating of lake sediment is in agreement with seismic profiles, sedimentologic analysis, and diatom frequency measurements both in an undisturbed as well as in a disturbed lake sediment.

Interstadial Conifer Wood from Northern Maine

1988 ◽  
Vol 30 (1) ◽  
pp. 98-101
Author(s):  
R. Scott Anderson ◽  
Ronald B. Davis ◽  
Robert Stuckenrath ◽  
Harold W. Borns
Keyword(s):  
Organic Matter ◽  
New England ◽  
Lake Sediments ◽  
Lake Sediment ◽  
Radiocarbon Dating ◽  
Late Glacial ◽  
Local Source ◽  
Northern New England ◽  
Upper South ◽  
Conifer Wood

Conifer wood, probably spruce (Picea sp.), of middle Wisconsinan age (29,200 ± 500 yr B.P.) was recovered from late-glacial lake sediments from Upper South Branch Pond, Maine. If the wood was derived from a local source, deglaciation of part of northern New England is suggested for this time. The occurrence also has implications for understanding the problem associated with radiocarbon dating of bulk lake sediment containing small amounts of organic matter.

Paleolimnology of Two Lakes in the Klutlan Glacier Region, Yukon Territory, Canada

1980 ◽  
Vol 14 (1) ◽  
pp. 149-168 ◽  
Author(s):  
J. Platt Bradbury ◽  
M. C. Whiteside
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Surface Sediment ◽  
Second Generation ◽  
Sediment Cores ◽  
Yukon Territory ◽  
Turbid Water ◽  
Baseline Information ◽  
Basin Formation ◽  
Diatom Stratigraphy

AbstractLakes developed on progressively younger end moraines of the Klutlan Glacier were initially assumed to have originated shortly after moraine emplacement and to have persisted to the present. Limnological differences between lakes on old vs young moraines were thought to result from limnological maturation within the lakes and ponds themselves and in response to the development of soils and vegetation on moraine surfaces. This study represents a paleolimnological test of this hypothesis. If true, the first-formed sediments of lakes on old moraines should be comparable to sediments presently forming in lakes on young moraines. Geochemical and paleontological studies of surface sediment to a series of lakes on progressively older moraines provide baseline information for comparing successive levels of lake sediment cores from older moraines. Results indicate that the time of lake initiation seldom reflects moraine age. Even on the oldest moraine (Harris Creek), lake basins are presently forming. Their sediment character more closely relates to the rapidity of basin formation due to melting of buried ice than to age of the lake itself or of the moraine on which it is situated. Vegetation and soil development play an important but secondary role in determining the character of lake sediments; rapid subsidence can convert humic-water lakes surrounded by second-generation spruce forests into turbid-water lakes with unstable, slumping margins. A detailed paleolimnological study of two lakes, one on the unglaciated upland and another in an outwash channel penetrating the oldest moraine, revealed progressive limnologic changes through time, suggesting that their basins were stable for 1200 and 400 yr, respectively. The changes in diatom stratigraphy of these lakes appear to relate to natural limnological changes associated with lake maturation and accumulation of nutrients as well as to changes in the surrounding vegetation and soils.

Interglacial Deposits at Birch Creek, Northeast Interior Alaska

1991 ◽  
Vol 35 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Mary E. Edwards ◽  
Patricia F. McDowell
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Radiocarbon Dating ◽  
Ancient Lake ◽  
High Exposure ◽  
Interior Alaska ◽  
M Sequence ◽  
Modern Landscape ◽  
Thaw Lakes

AbstractA 12-m sequence of lake sediment and peat in a 45-m high exposure on Birch Creek, northeast Alaska, contains pollen of Picea, Betula, Alnus and Populus, and wood of Picea and Populus. This sequence, which may represent 10,000 yr of more of accumulation, is beyond the limit of radiocarbon dating. It lies between two units of loess; the underlying loess lies above the Old Crow Tephra, recently dated at 149,000 ± 13,000 yr B.P. The lake sediments probably were deposited during the last interglaciation (isotope substage 5e) and subsequently buried by Wisconsinan loess. Analogs for the ancient lake may be deep, long-lived thaw lakes that are present in the modern landscape. When Birch Creek is correlated with other sites across nonglaciated Alaska and northwest Canada, there appears to be a common interglacial signal in sediments overlying the Old Crow Tephra.

scholarly journals A High-Resolution Geophysical Survey of Jenny Lake: Using Lake Sediments to Construct a Continuous Record of Tectonic Activity and Earthquake-Triggered Disturbances at Grand Teton National Park

2015 ◽  
Vol 38 ◽  
pp. 2-7
Author(s):  
Darren Larsen ◽  
Mark Abbot
Keyword(s):  
Lake Sediments ◽  
National Park ◽  
Sediment Cores ◽  
Tectonic Activity ◽  
Slope Failures ◽  
Grand Teton National Park ◽  
Field Investigations ◽  
History Of ◽  
Teton Range ◽  
Fault Scarps

The Teton Range, WY contains a legacy of late Cenozoic uplift and periodic Quaternary glaciations. Well-preserved fault scarps along the Teton fault displace glacier deposits from the most recent (Pinedale) glaciation and provide evidence for high fault activity during the past ~15,000 years. Observations of these scarps and previous field investigations indicate that postglacial fault offset occurred through a series of major, scarp-forming earthquakes. However, the postglacial paleoseismic record of the Teton fault remains incomplete. The goal of this project is to use lake sediments, contained in lake basins positioned on the fault, to construct a history of the timing and frequency of past earthquakes at Grand Teton National Park, and assess seismic impacts on diment erosion (e.g., landslides, debris flows, slope failures) and future hazard potential. Here, we report on multibeam sonar bathymetry and seismic reflection images from Jenny Lake, collected as part of an effort to identify glacial and tectonic landforms and to characterize infill stratigraphy. Our overarching objective is to combine these datasets with lake sediment cores from Jenny Lake and other nearby lakes to construct a continuous, accurately-dated record of past earthquakes and earthquake-generated slope failures in the Tetons.

Radiocarbon Dating of Pollen by Accelerator Mass Spectrometry

1989 ◽  
Vol 32 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Thomas A. Brown ◽  
D. Erle Nelson ◽  
Rolf W. Mathewes ◽  
John S. Vogel ◽  
John R. Southon
Keyword(s):  
Mass Spectrometry ◽  
Lake Sediment ◽  
Standard Method ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Bulk Sediment ◽  
Sediment Dating ◽  
First Time

AbstractRadiocarbon dating of bulk sediments has been the standard method for establishing chronologies in the studies of lake sediment cores which have contributed significantly to our knowledge of late Quaternary paleo-environments. These bulk sediment dates are presumed to be direct ageindicators for the speciments (e.g., pollen or macrofossils) which are actually being studied. However, several recent studies have reinforced long-standing apprehensions concerning this presumption. In this study, we demonstrate for the first time the radiocarbon dating of pollen concentrate samples by accelerator mass spectrometry. The dates obtained by this method should provide more reliable radiocarbon chronologies for paleo-environmental studies than have been obtainable by bulk sediment dating.

Geomorphology of the lakebed and sediment deposition during the Holocene in Lake Visovac

2021 ◽  
Author(s):  
Nikolina Ilijanić ◽  
Slobodan Miko ◽  
Ozren Hasan ◽  
Dea Brunović ◽  
Martina Šparica Miko ◽  
...  
Keyword(s):  
High Resolution ◽  
Lake Sediment ◽  
National Park ◽  
Lake Level ◽  
Evolutionary Dynamics ◽  
Environmental Changes ◽  
Sediment Cores ◽  
Depositional Environments ◽  
Lake Levels ◽  
The Holocene

<p>Lake Visovac is a tufa barrier lake on the Krka River between Roški slap (60 m asl) and Skradinski buk (46 m absl) waterfalls, included in the Krka national park as primarily unaltered area of exceptional natural value. Paleolimnological research was conceived to address a lake evolution and depositional environments through the geophysical survey and collection of the lake sediment cores. A high-resolution bathymetric map was obtained using a multibeam sonar. The average lake depth varies between 20 and 25 m. Sediment cores were investigated to extract physical properties, sedimentological, mineralogical, geochemical and paleoecological records constrained by the radiocarbon chronology, to understand what was happening to both the landscapes and lakescapes of Lake Visovac during the last 2.000 cal yr.</p><p>Significant findings of the project are geomorphological features on the lake bottom: submerged sinkholes of various sizes (up to 40 m deep); submerged tufa barriers in the area of Kalički kuk (southern part of Lake Visovac) at the depths of 15 and 17 m, followed by a series of buried cascade tufa barriers at the depth of 25 m covered with up to 10 m of Holocene lake sediments; submerged vertical tufa barrier up to 32 m-high near the mouth of Čikola River; submerged landslides, small (river) fan structures characterized by sediment waves. Ground-penetrating-radar (GPR) data have been acquired due to the presence of gas-saturated sediments over a large area of the lake, that limited the use of high-resolution acoustic profiling. A total thickness of sediments is up to 40 m. High resolution paleoenvironmental record through the Late Holocene gives evidence of high sedimentation rates in Lake Visovac, variable soil erosion impact on lake sediment composition and carbonate authigenic sedimentation. Higher organic carbon is observed in the last 50 years due to changes in land cover and reforestation. Pleistocene lake sediment outcrops occur up to 20 m above the present lake levels indicating higher lake levels as a consequence of higher elevation of tuffa barriers. Kalički kuk, which lies up to 20 m above present lake level, is a remnant of these barriers which have been dated to MIS5. Results allow us to interpret the environmental and evolutionary dynamics of Lake Visovac in the following way: lake level more than 20 m higher than today in mid-Pleistocene with significantly larger lake volume in Lake Visovac, with active Kalički kuk and Skradinski buk waterfalls; lower lake-level at the beginning of the Holocene when several small lakes existed in isolated basins in the area of Lake Visovac. The tufa barrier at Skradinski buk started to grow faster than the Kalički kuk barriers and waterfalls resulting in their flooding and submergence during the Holocene. The tufa barrier at Skradinski buk has grown 15 m since then. This study demonstrates the role of geomorphological lakebed characteristics in reshaping our understanding of the environmental changes and the future of Lake Visovac.</p><p>The research was conducted as part of the project funded by the Krka National Park and CSF funded QMAD project (IP-04-2019-8505).</p>

scholarly journals Application of Corrected Methods for High-Resolution XRF Core Scanning Elements in Lake Sediments

2020 ◽  
Vol 10 (22) ◽  
pp. 8012
Author(s):  
Xiaonan Zhang ◽  
Hucai Zhang ◽  
Fengqin Chang ◽  
Umar Ashraf ◽  
Wei Peng ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Content ◽  
Lake Sediments ◽  
Lake Sediment ◽  
Sediment Cores ◽  
Xrf Core Scanner ◽  
Calibration Methods ◽  
Xrf Scanning ◽  
The Impact ◽  
Log Ratio

Contemporary studies emphasize theoretical and analytical aspects of monitoring water quality within lacustrine settings. The X-ray fluorescence (XRF) core scanner provides the most rapid, non-destructive high-resolution elemental measurements for unprocessed sediments. However, the analytical precision of measured elemental composition may be offset due to water content and inhomogeneities in the physical properties of the sediment. A range of calibration approaches developed specifically for converting XRF scanning intensities to element fractions has been made available. Here, two lake sediment-cores retrieved from southwest China were used to evaluate the performance of various calibration methods. In particular, the influence of sediment properties on XRF scanning intensities was assessed by redundancy analyses (RDA) and the generalized additive model (GAM). The results demonstrate that for fine-grained sediments, the impact of grain size results in only minor deviations in the XRF scanning intensities. Water content of the lake sediment was shown to be the most important factor influencing the XRF scanning intensities, especially for light elements (e.g., Al to Fe). Significant decreases in XRF scanning intensities may occur when sediment water content is greater than 47%. We recommend testing the element fractions obtained via conventional techniques throughout the core and applying the multivariate log-ratio calibration for high-resolution XRF scanning elements within lake sediments.

Geology, Palynology, and Climatic Significance of Two Pre-Pinedale Lake Sediment Sequences in and Near Yellowstone National Park

1978 ◽  
Vol 10 (2) ◽  
pp. 226-240 ◽  
Author(s):  
Richard G. Baker ◽  
Gerald M. Richmond
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Pollen Analysis ◽  
Yellowstone National Park ◽  
National Park ◽  
Pine Forest ◽  
Tundra Vegetation ◽  
Wood Debris ◽  
Lake Deposits

Pollen analysis of a section of lake sediments at Grassy Lake Reservoir indicates a vegetational sequence changing from tundra, to spruce-fir-pine forest, to pine forest, to tundra at the top. Pollen analysis of a section of lake sediments on Beaverdam Creek indicates a tundra vegetation at the base, followed by a brief episode of spruce-fir forest and a return to a tundra vegetation at the top. The analyses of both sections suggest a cold to cool to cold climatic sequence, interpreted as interstadial in character. However, differences suggest that they represent separate interstadials. Pinedale Till disconformably overlies the lake deposits at Grassy Lake Reservoir. The upper sediments contain wood 14C dated at >42,000 yr; the lowermost interfinger with till shown to be more than about 70,000 yr old. The deposits at Beaverdam Creek grade upward into proglacial Pinedale deposits, contain an ash that is probably about 70,000 yr old near their base, and rest comformably on gravel that grades down into lake sediments containing wood debris suggestive of an older climatic amelioration. We conclude that the warmest part of the interstadial at Grassy Lake Reservoir is probably more than 70,000 yr old, and that the warmest part of the interstadial analyzed at Beaverdam Creek is slightly younger than 70,000 yr old.

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