Lake Michigan Beach-Ridge and Dune Development, Lake Level, and Variability in Regional Water Balance

1995 ◽  
Vol 44 (2) ◽  
pp. 181-189 ◽  
Author(s):  
John Lichter
Keyword(s):  
Water Balance ◽  
Lake Level ◽  
Lake Michigan ◽  
Plant Macrofossils ◽  
Time Intervals ◽  
Beach Ridges ◽  
Average Return ◽  
High Lake Level ◽  
High Level ◽  
Regional Water

AbstractA sequence of northern Lake Michigan beach ridges records lake-level fluctuations that are probably related to changes in late Holocene climate. Historically, episodes of falling and low lake level associated with regional drought led to the formation of dune-capped beach ridges. The timing of prehistoric ridge formation, estimated by radiocarbon dating of plant macrofossils from early-successional dune species, shows that return periods of inferred drought, averaged for time intervals of 100 to 480 yr, ranged between 17 and 135 yr per drought during the last 2400 yr. In five of ten of these time intervals, the average return period ranged between 17 and 22 yr per drought. These intervals of frequent ridge formation and drought were associated with the development of parabolic dunes, which is indicative of high lake level and moist climate. This seeming paradox suggests that unusually moist decades alternated with unusually dry decades during these time intervals. Regional water balance probably varied less during the time intervals when ridges formed less often and the lake produced no evidence of high level.

AMS Radiocarbon Dating of Lake Michigan Beach-Ridge and Dune Development

1997 ◽  
Vol 48 (1) ◽  
pp. 137-140 ◽  
Author(s):  
John Lichter
Keyword(s):  
Radiocarbon Dating ◽  
Lake Level ◽  
Sand Dune ◽  
Lake Michigan ◽  
Beach Ridge ◽  
Radiocarbon Dates ◽  
Beach Ridges ◽  
Ams Radiocarbon Dating ◽  
Climate Fluctuations ◽  
Radiocarbon Chronology

Strandplains of shore-parallel beach ridges bordering the Great Lakes are valuable for reconstructing histories of climate-related lake-level fluctuations. However, imprecise radiocarbon dates of ridge formation have frustrated development of dependable chronologies from which information about variation in the frequency of ridge formation and inferred climate fluctuations can be obtained. The resolution and precision of radiocarbon chronologies can be improved with AMS 14C dates of roots and rhizomes of plant species associated with the formation and growth of the sand-dune caps of breach ridges. These dates reliably estimate the timing of shore progradation when the base of the previously established beach ridge becomes inundated by the water table. An AMS radiocarbon chronology of beach-ridge formation in northern Lake Michigan shows that information about variation in the frequency of ridge formation is important for paleoclimatic interpretation.

scholarly journals Extent of Sedge/Grass Meadow in a Lake Michigan Drowned-River-Mouth Wetland Dictated by Topography/Bathymetry and Lake Level

2021 ◽  
Author(s):  
Douglas A. Wilcox ◽  
John Bateman ◽  
Kurt Kowalski ◽  
James Meeker ◽  
Nicole Dunn
Keyword(s):  
Great Lakes ◽  
Plant Communities ◽  
Lake Level ◽  
Lake Michigan ◽  
River Mouth ◽  
Water Level Fluctuations ◽  
Lake Levels ◽  
High Lake Level ◽  
Grass Meadow ◽  
High Lake Levels

Abstract Water-level fluctuations are critical in maintaining the diversity of plant communities in Great Lakes wetlands. Sedge/grass meadows are especially sensitive to such fluctuations. We conducted vegetation sampling in a sedge/grass-dominated Lake Michigan drowned-river-mouth wetland in 1995, 2002, and 2010 that followed high lake levels in 1986 and 1997. We also conducted photointerpretation studies in 16 years dating back to 1965 to include responses to high lake level in 1952 and 1974. Topographic/bathymetric data were collected to assess their influence on areal extent of sedge/grass meadow. Dominant species in short emergent and submersed/floating plant communities changed with water availability from 1995 to extreme low lake levels in 2002 and 2010. Sedge/grass meadow was dominated by Calamagrostis canadensis and Carex stricta in all years sampled, but Importance Values differed among years partly due to sampling in newly exposed areas. Photointerpretation studies showed a significant relation between percent of wetland in sedge/grass meadow and summer lake level, as well as the number of years since an extreme high lake level. From the topographic/bathymetric map created, we calculated the cumulative area above each 0.2-m contour to determine the percent of wetland dewatered in select years following extreme high lake levels. When compared with percent sedge/grass meadow in those years, relative changes in both predicted land surface and sedge/grass meadow demonstrated that accuracy of lake level as a predictor of area of sedge/grass meadow is dependent on topography/bathymetry. Our results regarding relations of plant-community response to hydrology are applicable to other Great Lakes wetlands.

Regional Water Balance and Economic Assessment as Tools for Water Management in Coastal Lebanon

2008 ◽  
Vol 23 (11) ◽  
pp. 2361-2378 ◽  
Author(s):  
Daniel El Chami ◽  
Maroun El Moujabber ◽  
Alessandra Scardigno
Keyword(s):  
Water Management ◽  
Water Balance ◽  
Economic Assessment ◽  
Regional Water

A New and Open CoiledValvata(Gastropoda) from the Pliocene Koobi Fora Formation of the Turkana Basin, Northern Kenya

2010 ◽  
Vol 84 (5) ◽  
pp. 996-1002 ◽  
Author(s):  
Henning Scholz ◽  
Matthias Glaubrecht
Keyword(s):  
New Species ◽  
Environmental Stress ◽  
Environmental Conditions ◽  
Lake Level ◽  
Shell Morphology ◽  
Koobi Fora ◽  
Northern Kenya ◽  
Turkana Basin ◽  
High Level ◽  
Stratigraphic Interval

New field collections allow the study and description ofValvata juliaenew species from the Pliocene upper Burgi Member of the Koobi Fora Formation of Kenya. The shell morphology of this species varies from trochospiral to planispiral to open coiled. The species is restricted to a short stratigraphic interval.Valvata juliaeis considered as an invader of the Turkana Basin during a lacustrine transgression event. The open coiling of the species is interpreted as an ecophenotypic response to a high level of environmental stress caused by lake level fluctuations and emergence of delta systems. These environmental conditions broughtValvata juliaeto extinction soon after it invaded the Turkana Basin.

Late-Holocene Formation of Lake Michigan Beach Ridges Correlated with a 70-yr Oscillation in Global Climate

1996 ◽  
Vol 45 (3) ◽  
pp. 321-326 ◽  
Author(s):  
Paul A. Delcourt ◽  
William H. Petty ◽  
Hazel R. Delcourt
Keyword(s):  
Late Holocene ◽  
Lake Michigan ◽  
Global Climate ◽  
Temperature Oscillation ◽  
Beach Ridges ◽  
Climate Fluctuations ◽  
The Past ◽  
Fundamental Part ◽  
Atmosphere System ◽  
Centennial Time Scale

AbstractA radiocarbon-dated series of 75 beach ridges, formed at regular intervals averaging 72 yr over the past 5400 yr, provides further support for the existence of a 70-yr oscillation in Northern Hemisphere climate, postulated recently from instrument data representing less than two cycles of this climate oscillation. Results from this study lend support to the interpretation that internal variations in the ocean–atmosphere system are an important factor in climate fluctuations on a decadal–centennial time scale. A temperature oscillation with a period of about 70 yr has been a previously unrecognized but fundamental part of the global climate system since at least the middle Holocene.

Glacial-Lake Outburst Erosion of the Grand Valley, Michigan, and Impacts on Glacial Lakes in the Lake Michigan Basin

1993 ◽  
Vol 39 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Alan E. Kehew
Keyword(s):  
Lake Level ◽  
Lake Michigan ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
Michigan Basin ◽  
Lake Agassiz ◽  
Lake Algonquin ◽  
Lake Michigan Lobe ◽  
Possible Cause ◽  
Glacial Lake Algonquin

AbstractGeomorphic and sedimentologic evidence in the Grand Valley, which drained the retreating Saginaw Lobe of the Laurentide Ice Sheet and later acted as a spillway between lakes in the Huron and Erie basins and in the Michigan basin, suggests that at least one drainage event from glacial Lake Saginaw to glacial Lake Chicago was a catastrophic outburst that deeply incised the valley. Analysis of shoreline and outlet geomorphology at the Chicago outlet supports J H Bretz's hypothesis of episodic incision and lake-level change. Shoreline features of each lake level converge to separate outlet sills that decrease in elevation from the oldest to youngest lake phases. This evidence, coupled with the presence of boulder lags and other features consistent with outburst origin, suggests that the outlets were deepened by catastrophic outbursts at least twice. The first incision event is correlated with a linked series of floods that progressed from Huron and Erie basin lakes to glacial Lake Saginaw to glacial Lake Chicago and then to the Mississippi. The second downcutting event occurred after the Two Rivers Advance of the Lake Michigan Lobe. Outbursts from the eastern outlets of glacial Lake Agassiz to glacial Lake Algonquin are a possible cause for this period of downcutting at the Chicago outlets.

A lake-level chronology based on feldspar luminescence dating of beach ridges at Tangra Yum Co (Southern Tibet)

2015 ◽  
Vol 83 (3) ◽  
pp. 469-478 ◽  
Author(s):  
Eike F. Rades ◽  
Sumiko Tsukamoto ◽  
Manfred Frechen ◽  
Qiang Xu ◽  
Lin Ding
Keyword(s):  
Tibetan Plateau ◽  
Lake Level ◽  
Environmental Changes ◽  
Luminescence Dating ◽  
Rapid Decline ◽  
The Tibetan Plateau ◽  
Southern Tibet ◽  
Beach Ridges ◽  
Slow Decline ◽  
Fast Decline

Many lakes on the Tibetan Plateau exhibit strandplains with a series of beach ridges extending high above the current lake levels. These beach ridges mark former lake highstands and therefore dating their formation allows the reconstruction of lake-level histories and environmental changes. In this study, we establish a lake-level chronology of Tangra Yum Co (fifth largest lake on the Tibetan Plateau) based on luminescence dating of feldspar from 17 beach-ridge samples. The samples were collected from two strandplains southeast and north of the lake and range in elevation from the current shore to 140 m above the present lake. Using a modified post-infrared IRSL protocol at 170°C we successfully minimised the anomalous fading in the feldspar IRSL signal, and obtained reliable dating results. The luminescence ages indicate three different stages of lake-level decline during the Holocene: (1) a phase of rapid decline (~ 50 m) from ~ 6.4 to ~ 4.5 ka, (2) a period of slow decline between ~ 4.5 and ~ 2.0 ka (~ 20 m), and (3) a fast decline by 70 m between ~ 2 ka and today. Our findings suggest a link between a decrease in monsoonal activity and lake-level decline since the early Holocene.

Study of the effect of using a hard toothbrush with a high abrasive toothpaste according to profilometry data

2021 ◽  
Vol 1 (38) ◽  
pp. 41-44
Author(s):  
S. N. Razumova ◽  
Y. S. Kozlova ◽  
А. S. Brago ◽  
N. M. Razumov ◽  
T. A. Glybina
Keyword(s):  
Oral Hygiene ◽  
Optimal Combination ◽  
Enamel Surface ◽  
Initial Condition ◽  
Time Intervals ◽  
Hard Tissues ◽  
Dental Diseases ◽  
High Level ◽  
Prevention Of Dental Diseases

Compliance with oral hygiene is an important aspect of the prevention of dental diseases. But an uncontrolled choice, the use of improperly selected home hygiene products can lead to a number of complications, for example hyperesthesia of dentin. An important aspect of the choice of home hygiene products is their effect on the hard tissues of the tooth.Aim. To study in the experiment the effect of a hard toothbrush with a high level of abrasiveness of a toothpaste on the change in the enamel surface according to profilometry data.Materials and methods. Using the device for cleaning teeth, a study was carried out on the roughness of the surface if the enamel of the sample. In research were used the first 3 molars removed for periodontal indications, of which 3 samples of 1×1 cm were prepared. The measurements were carried out using a Senso neox profilometer (Sensofar) with a 3D magnification of 150 at the following time intervals: initial condition of the tooth, 1 week, 1 month, 6 months, 1 year.Conclusion. When using a hard toothbrush together in combination with a highly abrasive paste, the optimal combination time is not more than 6 months. Further, there is an increase in roughness of enamel surface.

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