scholarly journals Climate in the Great Lakes Region Between 14,000 and 4000 Years Ago from Isotopic Composition of Conifer Wood

Radiocarbon ◽  
2006 ◽  
Vol 48 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Steven W Leavitt ◽  
Irina P Panyushkina ◽  
Todd Lange ◽  
Alex Wiedenhoeft ◽  
Li Cheng ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Great Lakes ◽  
Cross Sections ◽  
Lake Michigan ◽  
Laurentide Ice Sheet ◽  
Great Lakes Region ◽  
Floristic Similarity ◽  
Ancient Wood ◽  
Conifer Trees ◽  
Conifer Wood

The isotopic composition of ancient wood has the potential to provide information about past environments. We analyzed the δ13C, δ18O, and δ2H of cellulose of conifer trees from several cross-sections at each of 9 sites around the Great Lakes region ranging from ∼4000 to 14,000 cal BP. Isotopic values of Picea, Pinus, and Thuja species seem interchangeable for δ18O and δ2H comparisons, but Thuja appears distinctly different from the other 2 in its δ13C composition. Isotopic results suggest that the 2 sites of near-Younger Dryas age experienced the coldest conditions, although the Gribben Basin site near the Laurentide ice sheet was relatively dry, whereas the Liverpool site 500 km south was moister. The spatial isotopic variability of 3 of the 4 sites of Two Creeks age shows evidence of an elevation effect, perhaps related to sites farther inland from the Lake Michigan shoreline experiencing warmer daytime growing season temperatures. Thus, despite floristic similarity across sites (wood samples at 7 of the sites being Picea), the isotopes appear to reflect environmental differences that might not be readily evident from a purely floristic interpretation of macrofossil or pollen identification.

Retreat of the Laurentide Ice Sheet from 14,000 to 9000 Years Ago

1971 ◽  
Vol 1 (3) ◽  
pp. 316-330 ◽  
Author(s):  
H. E. Wright
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Lake Superior ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Great Lakes Region ◽  
Forward Movement ◽  
Western Lake ◽  
Basal Sliding ◽  
Lake Michigan Lobe

The intricate pattern of moraines of the Laurentide ice sheet in the Great Lakes region reflects the marked lobation of the ice margin in late Wisconsin time, and this in turn reflects the distribution of steam-cut lowlands etched in preglacial times in the weak-rock belts of gentle Paleozoic fold structures. It is difficult to trace and correlate moraines from lobe to lobe and to evaluate the magnitude of recession before readvance, but three breaks stand out in the sequence, with readvances at about 14,500, 13,000, and 11,500 years ago. The first, corresponding to the Cary advance of the Lake Michigan lobe, is represented to the west by distant advance of the Des Moines lobe in Iowa, and to the east by the overriding of lake beds by the Erie lobe. The 13,000-year advance is best represented by the Port Huron moraine of the Lake Michigan and Huron lobes, but by relatively little action to west and east. The 11,500-year advance is based on the Valders till of the Lake Michigan lobe, but presumed correlations to east and west prove to be generally older, and the question is raised that these and some other ice advances in the Great Lakes region may represent surges of the ice rather than regional climatic change. Surging may involve the buildup of subglacial meltwater, which can provide the basal sliding necessary for rapid forward movement. It would be most favored by the conditions in the western Lake Superior basin, where the Superior lobe had a suitable form and thermal regime, as estimated from geomorphic and paleoclimatic criteria. The Valders advance of the Lake Michigan and Green Bay lobes may also have resulted from a surge: the eastern part of the Lake Superior basin, whence the ice advanced, has a pattern of deep gorges that resemble subglacial tunnel valleys, which imply great quantities of subglacial water that may have produced glacial surges before the water became channeled.

Aztalan and the Northern Tier of a Cahokia Hinterland

2020 ◽  
pp. 107-127 ◽  
Author(s):  
John D. Richards
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
River Valley ◽  
Illinois River ◽  
Great Lakes Region ◽  
Upper Great Lakes ◽  
Illinois River Valley ◽  
Wide Range ◽  
Western Shore ◽  
Central Illinois

Cahokia’s northern hinterland can be conceptualized as extending north from the central Illinois River valley into the western and upper Great Lakes region. The northern tier of this hinterland can be thought of as a region north of the Apple River area of northwest Illinois and south of a line extending east from the mouth of the St. Croix River to the western shore of Lake Michigan. This area includes a wide range of landscapes, biotas, and cultures and this diversity is mirrored in the Cahokia-related manifestations found throughout the region. This chapter provides a brief comparison of three northern tier sites/complexes including Trempealeau, Fred Edwards, and Aztalan in order to highlight the diversity of Mississippian-related occupations in the area.

scholarly journals THE MAIN ORE UNLOADING DOCK FAILURES AND THEIR CORRECTION 1909-1925, GREAT LAKES REGION

2000 ◽  
Vol 1 (4) ◽  
pp. 22
Author(s):  
E. James Fucik
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Great Lakes Region ◽  
The South ◽  
Corps Of Engineers ◽  
Chicago River

To start at the beginning of Chicago's lake structures (and first attempts to hold back ware action) we will go back about 120 years, to the year 1833. At that time an Illinois Congressman put through Congress an appropriation of $25,000 to construct a harbor at the south end of Lake Michigan (Fig. 1). At that time the Chicago River was navigable only by canoes. That Congressman, however, argued that the harbor should be located eleven miles south at the Calumet River. He was out-argued by a Captain of the Corps of Engineers, U.S. Army, who prevailed, and two 500 foot piers were built at the mouth of the Chicago River. The Congressman's name was Stephen A. Douglass and the Captain's name was Jefferson Davis, who evidently was a very persuasive fellow. These piers were either wooden cribs filled with stone, or stone-filled pile piers.

A Proposed Diachronic Revision of Late Quaternary Time-Stratigraphic Classification in the Eastern and Northern Great Lakes Area

2000 ◽  
Vol 54 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Paul F. Karrow ◽  
Aleksis Dreimanis ◽  
Peter J. Barnett
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Late Quaternary ◽  
Great Lakes Region ◽  
Quaternary Deposits ◽  
Late Wisconsinan ◽  
Stratigraphic Nomenclature ◽  
Lake Michigan Lobe

A succession of stratigraphic codes (1933, 1961, 1983) has guided attempts to refine classifications and naming of stratigraphic units for Quaternary deposits of the Great Lakes region. The most recent classifications for the late Quaternary of the Lake Michigan lobe (1968) and the eastern Great Lakes (1972) have been widely used, but later work has created the need for revision. An attempt has been made to integrate the two previous classifications following the diachronic system of the 1983 Code of Stratigraphic Nomenclature. A new nomenclature for the higher, more broadly recognized units was presented in 1997. We here present the diachronic nomenclature for finer subdivisions recognized in the eastern and northern Great Lakes. Following the interglacial Sangamon Episode, the three parts of the Wisconsin Episode are further subdivided as follows: the Ontario Subepisode (former Early Wisconsinan) comprises the Greenwood, Willowvale, and Guildwood phases; the Elgin Subepisode (former Middle Wisconsinan) comprises the Port Talbot, Brimley, and Farmdale phases; and the Michigan Subepisode (former Late Wisconsinan) consists of Nissouri, Erie, Port Bruce, Mackinaw, Port Huron, Two Creeks, Onaway, Gribben, Marquette, Abitibi, and Driftwood phases. Succeeding interglacial time to the present is the Hudson Episode.

Glacial isostatic adjustment at the Laurentide ice sheet margin: Models and observations in the Great Lakes region

2008 ◽  
Vol 46 (3-5) ◽  
pp. 165-173 ◽  
Author(s):  
Alexander Braun ◽  
Chung-Yen Kuo ◽  
C.K. Shum ◽  
Patrick Wu ◽  
Wouter van der Wal ◽  
...  
Keyword(s):  
Great Lakes ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Great Lakes Region ◽  
Glacial Isostatic Adjustment ◽  
Isostatic Adjustment

scholarly journals Periodic structures of Great Lakes levels using wavelet analysis

2011 ◽  
Vol 59 (1) ◽  
pp. 24-35 ◽  
Author(s):  
Taner Cengiz
Keyword(s):  
Wavelet Transform ◽  
Great Lakes ◽  
Lake Level ◽  
Lake Erie ◽  
Lake Michigan ◽  
Periodic Structures ◽  
Lake Superior ◽  
Great Lakes Region ◽  
Continuous Wavelet ◽  
Lake Levels

Periodic structures of Great Lakes levels using wavelet analysisThe recently advanced approach of wavelet transforms is applied to the analysis of lake levels. The aim of this study is to investigate the variability of lake levels in four lakes in the Great Lakes region where the method of continuous wavelet transform and global spectra are used. The analysis of lake-level variations in the time-scale domain incorporates the method of continuous wavelet transform and the global spectrum. Four lake levels, Lake Erie, Lake Michigan, Lake Ontario, and Lake Superior in the Great Lakes region were selected for the analysis. Monthly lake level records at selected locations were analyzed by wavelet transform for the period 1919 to 2004. The periodic structures of the Great Lakes levels revealed a spectrum between the 1-year and 43- year scale level. It is found that major lake levels periodicities are generally the annual cycle. Lake Michigan levels show different periodicities from Lake Erie and Lake Superior and Lake Ontario levels. Lake Michigan showed generally long-term (more than 10 years) periodicities. It was shown that the Michigan Lake shows much stronger influences of inter-annual atmospheric variability than the other three lakes. The other result was that some interesting correlations between global spectrums of the lake levels from the same climatic region were found.

scholarly journals An Investigation of Cold-Season Short-Wave Troughs in the Great Lakes Region and Their Concurrence with Lake-Effect Clouds

2019 ◽  
Vol 58 (3) ◽  
pp. 605-614 ◽  
Author(s):  
Nicholas D. Metz ◽  
Zachary S. Bruick ◽  
Peyton K. Capute ◽  
Molly M. Neureuter ◽  
Emily W. Ott ◽  
...  
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Short Wave ◽  
Cold Season ◽  
Great Lakes Region ◽  
Cloud Band ◽  
Wave Trough ◽  
Long Wave ◽  
Lake Effect ◽  
Concurrent Events

AbstractThe downwind shores of the Laurentian Great Lakes region often receive prolific amounts of lake-effect snowfall during the cold season (October–March). The location and intensity of this snowfall can be influenced by upper-tropospheric features such as short-wave troughs. A 7-yr cold-season climatology of 500-hPa short-wave troughs was developed for the Great Lakes region. A total of 607 short-wave troughs were identified, with an average of approximately 87 short waves per cold season. Five classes of short-wave troughs were identified on the basis of their movement through the Great Lakes region. This short-wave trough dataset was subsequently compared with the lake-effect cloud-band climatology created by N. F. Laird et al. in 2017 to determine how frequently short-wave troughs occurred concurrently with lake-effect cloud bands. Of the 607 short-wave troughs identified, 380 were concurrent with lake-effect clouds. Over 65% of these 380 short-wave troughs occurred with a lake-effect cloud band on at least four of the five Great Lakes. Short-wave troughs that rotated around the base of a long-wave trough were found to have the highest frequency of concurrence. In general, concurrence was most likely during the middle cold-season months. Further, Lake Michigan featured the highest number of concurrent events, and Lake Erie featured the fewest. It is evident that short-wave troughs are a ubiquitous feature near the Great Lakes during the cold season and have the potential to impart substantial impacts on lake-effect snowbands.

scholarly journals Investigating diversity of pathogenic microbes in commercial bait trade water

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5468 ◽  
Author(s):  
Andrew R. Mahon ◽  
Dean J. Horton ◽  
Deric R. Learman ◽  
Lucas R. Nathan ◽  
Christopher L. Jerde
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Hypervariable Region ◽  
Environmental Dna ◽  
Taxonomic Diversity ◽  
Aquatic Systems ◽  
Rrna Gene ◽  
Great Lakes Region ◽  
Pathogen Diversity ◽  
Important Pathway

The recreational bait trade is a potential pathway for pathogen introduction and spread when anglers dump bait shop sourced water into aquatic systems. Despite this possibility, and previous recognition of the importance of the bait trade in the spread of aquatic invasive species (AIS), to date there has been no region wide survey documenting pathogens in retail bait shops. In this study, we analyzed 96 environmental DNA samples from retail bait shops around the Great Lakes region to identify pathogens, targeting the V4 hypervariable region of the 16S rRNA gene. Additionally, we used samples from one site in Lake Michigan as a comparison to pathogen diversity and abundance in natural aquatic systems. Our results identified nine different groups of pathogens in the bait shop samples, including those that pose risks to both humans and fish species. Compared to wild sourced samples, the bait shops had higher relative abundance and greater taxonomic diversity. These findings suggest that the bait trade represents a potentially important pathway that could introduce and spread pathogens throughout the Great Lakes region. Improving pathogen screening and angler outreach should be used in combination to aid in preventing the future spread of high risk pathogens.

scholarly journals Palimpsest tunnel valleys: evidence for relative timing of advances in an interlobate area of the Laurentide ice sheet

1999 ◽  
Vol 28 ◽  
pp. 47-52 ◽  
Author(s):  
Alan E. Kehew ◽  
Linda P. Nicks ◽  
W. Thomas Straw
Keyword(s):  
North America ◽  
Lake Michigan ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Great Lakes Region ◽  
Relative Timing ◽  
Outburst Flood ◽  
Flow Lines ◽  
Lake Michigan Lobe ◽  
East West

AbstractDuring retreat from the lateWisconsinan maximum advance in the Great Lakes region of North America, the Laurentide ice sheet margin became distinctly lobate. The Lake Michigan, Saginaw, and Huron—Erie lobes converged in southern Michigan and Indiana, U.S.A. to form a complex interlobate region. Some time after the glacial maximum, the Lake Michigan lobe advanced over landscapes previously formed by the Saginaw lobe. This can be explained by an asynchronous advance of the Lake Michigan lobe during a Saginaw lobe retreat or by an increase in size of the Lake Michigan lobe relative to the Saginaw lobe during a synchronous readvance.Cross-cutting relationships in southwestern Michigan, including palimpsest tunnel valleys, document the overriding of Saginaw lobe terrain. Deep, generally straight trenches parallel to glacial flow lines with hummocky, irregular sides and bottoms are interpreted as tunnel valleys. Saginaw lobe tunnel valleys trend northeast—southwest and Lake Michigan lobe tunnel valleys generally trend east—west.At some time after a Saginaw lobe retreat in southern Michigan, the drumlinized landscape was overridden by an advance of the Lake Michigan lobe to an ice-marginal position at the Tekonsha moraine. Saginaw lobe tunnel valleys in the overridden area were completely filled with ice and debris from the Saginaw lobe retreat at the time of the Lake Michigan lobe advance. Supraglacial and proglacial sediments were deposited over the buried valleys by the Lake Michigan lobe, sometimes by meltwater streams that flowed at high angles to the trends of the valleys. After entrenchment of the Kalamazoo River valley, probably by a subglacial outburst flood, short tributaries were cut nearly at right angles across and through the debris and ice within several buried Saginaw lobe tunnel valleys. After the retreat of the Lake Michigan lobe, subsequent melting of ice in the palimpsest tunnel valleys exhumed the valleys, creating the cross-cutting relationships with the Lake Michigan lobe deposits.

scholarly journals Examination of Nudging Schemes in the Simulation of Meteorology for Use in Air Quality Experiments: Application in the Great Lakes Region

2019 ◽  
Vol 58 (11) ◽  
pp. 2421-2436 ◽  
Author(s):  
M. Talat Odman ◽  
Andrew T. White ◽  
Kevin Doty ◽  
Richard T. McNider ◽  
Arastoo Pour-Biazar ◽  
...  
Keyword(s):  
Air Quality ◽  
Great Lakes ◽  
Large Scale ◽  
Lake Michigan ◽  
Forecast Errors ◽  
Great Lakes Region ◽  
Air Quality Model ◽  
Quality Model ◽  
Four Dimensional Data Assimilation ◽  
The Impact

AbstractHigh levels of ozone have been observed along the shores of Lake Michigan for the last 40 years. Models continue to struggle in their ability to replicate ozone behavior in the region. In the retrospective way in which models are used in air quality regulation development, nudging or four-dimensional data assimilation (FDDA) of the large-scale environment is important for constraining model forecast errors. Here, paths for incorporating large-scale meteorological conditions but retaining model mesoscale structure are evaluated. For the July 2011 case studied here, iterative FDDA strategies did not improve mesoscale performance in the Great Lakes region in terms of diurnal trends or monthly averaged statistics, with overestimations of nighttime wind speed remaining as an issue. Two vertical nudging strategies were evaluated for their effects on the development of nocturnal low-level jets (LLJ) and their impacts on air quality simulations. Nudging only above the planetary boundary layer, which has been a standard option in many air quality simulations, significantly dampened the amplitude of LLJ relative to nudging only above a height of 2 km. While the LLJ was preserved with nudging only above 2 km, there was some deterioration in wind performance when compared with profiler networks above the jet between 500 m and 2 km. In examining the impact of nudging strategies on air quality performance of the Community Multiscale Air Quality model, it was found that performance was improved for the case of nudging above 2 km. This result may reflect the importance of the LLJ in transport or perhaps a change in mixing in the models.

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