Glacial landsystems and dynamics of the Saginaw Lobe of the Laurentide Ice Sheet, Michigan, USA (original) (raw)
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Annals of Glaciology, 1999
During 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 ...
Geomorphology, 2008
This study focuses on the upper part of the Muskegon River system in north-central Lower Michigan and is the first to reconstruct the post-glacial history of fluvial landform development in the core of North America's Great Lakes region. Results indicate that the upper Muskegon River valley contains four alluvial terraces and numerous paleomeanders. Radiocarbon dating of peats within these old channels provides a good chronology for stream behavior and landform development. The T-4 terrace is a paired Pleistocene outwash/lacustrine surface that probably formed about 12,500 years ago. The T-3 terrace is a fill-strath surface that was cut between about 12,000 and perhaps 9500 years ago. The geometry of macromeanders on this surface suggests that stream discharge was ∼ 8 times greater than during the Holocene. The Pleistocene/Holocene transition is marked by a major period of downcutting that likely began as the climate warmed/dried and sediment yield diminished. This period of downcutting potentially lasted through the drier middle Holocene, creating a 6-m-high escarpment in the valley. The Muskegon River then began to aggrade when the climate became wetter. Subsequently the river again incised, creating the paired T-2 terrace, about 3400 years ago when the climate became still wetter. T-2 paleomeanders indicate that stream discharge at this time was consistent with the modern river. In the past 2500 years, the stream has constructed a poorly defined complex of T-1 terraces. These surfaces likely formed due to complex response associated with more variable climate. This study demonstrates that the upper Muskegon River has a similar post-glacial history as streams on deglacial and periglacial landscapes elsewhere in the world.
Annals of The Association of American Geographers, 2009
We identified, mapped, and characterized a widespread area (>1,020 km 2) of patterned ground in the Saginaw Lowlands of Michigan, a wet, flat plain composed of waterlain tills, lacustrine deposits, or both. The polygonal patterned ground is interpreted as a possible relict permafrost feature, formed in the Late Wisconsin when this area was proximal to the Laurentide ice sheet. Cold-air drainage off the ice sheet might have pooled in the Saginaw Lowlands, which sloped toward the ice margin, possibly creating widespread but short-lived permafrost on this glacial lake plain. The majority of the polygons occur between the Glacial Lake Warren strandline (∼14.8 cal. ka) and the shoreline of Glacial Lake Elkton (∼14.3 cal. ka), providing a relative age bracket for the patterned ground. Most of the polygons formed in dense, wet, silt loam soils on flat-lying sites and take the form of reticulate nets with polygon long axes of 150 to 160 m and short axes of 60 to 90 m. Interpolygon swales, often shown as dark curvilinears on aerial photographs, are typically slightly lower than are the polygon centers they bound. Some portions of these interpolygon swales are infilled with gravel-free, sandy loam sediments. The subtle morphology and sedimentological characteristics of the patterned ground in the Saginaw Lowlands suggest that thermokarst erosion, rather than ice-wedge replacement, was the dominant geomorphic process associated with the degradation of the Late-Wisconsin permafrost in the study area and, therefore, was primarily responsible for the soil patterns seen there today.
Genesis of streamlined landforms and flow history of the Green Bay Lobe, Wisconsin, USA
Sedimentary Geology, 1997
The distribution of streamlined landforms in southeastern Wisconsin suggests that drumlins and flutes formed during several phases of the Green Bay Lobe between 18 and 14,000 BP. The largest group of drumlins formed during a still-stand of the ice margin during the Johnstown phase, presumably about 18-16,000 BP. Flutes and smaller drumlins are superimposed on larger forms, and larger drumlins are remolded. This indicates that drumlin modification continued during retreat. Three fields containing smaller drumlins formed after ice re-advanced a short distance or stabilized during the Green Lake, Rush Lake, and St. Anna phases about 16-14,000 BP.
2017
In association with an undergraduate Honors Seminar at Michigan State University, we studied two small kame deltas in north-central Lower Michigan. These recently identified deltas provide clear evidence for a previously unknown proglacial lake (Glacial Lake Roscommon) in this large basin located in an interlobate upland. Our first goal was to document and characterize the geomorphology of these deltas. Because both deltas are tied to ice-contact ridges that mark the former position of the retreating ice margin within the lake, our second goal was to establish the age of one of the deltas, thereby constraining the timing of ice retreat in this part of Michigan, for which little information currently exists. Both deltas are composed of well-sorted fine and medium sands with little gravel, and have broad, nearly flat surfaces and comparatively steep fronts. Samples taken from the upper 1.5 m of the deltas show little spatial variation in texture, aside from a general fining toward the...
Postglacial Landscape Evolution of Northeastern Lower Michigan, Interpreted from Soils and Sediments
Annals of the Association of American Geographers, 2000
In this study, we used spatial data on soils, near-surface stratigraphy, and paleotopography to reinterpret part of the Late Pleistocene history of northeastern (NE) lower Michigan. We determined the relationships between various soil series and their likely sedimentary environments. Maps of these soil series for two counties in NE lower Michigan were then prepared within a geographic information system (GIS) to interpret the spatial patterns of the sedimentary environments on the paleolandscape which had been "downwarped" within a GIS to account for isostatic rebound. Our primary finding centers on the origin and distribution of clayey, lacustrine sediments in the region. These clays are found in swales between drumlins and on ground moraines. They occur, however, at elevations up to 60 m above any previously known paleolake. Although it is widely known that low-lying, clay-dominated areas near the Lake Huron and Lake Michigan basins were inundated by paleolakes in the Late Pleistocene, thick deposits of lacustrine sediments between drumlins in the high interior of this region suggest that it, too, was periodically submerged between 11,200 and 13,000 yrs B.P. Additionally, the crests of these drumlins are covered with 50-100 cm of sediment that appears to have been water-worked at some time in the past, overlying a denser, less altered till. We argue that a previously unknown lake, or series of interconnected lakes, existed across the uplands of this landscape. Stratified silts and clays were deposited beneath this water body, which was ponded between the Port Huron moraine to the south and an advancing, stagnant, or retreating ice margin to the north and east, and may have discharged to the south across a low section of the moraine. Our findings underscore the complex interactions among ice sheets, meltwater, and preexisting landscapes during final deglaciation, and should assist those who seek to understand and explain modern soil and biotic patterns on those landscapes. We hope that our preliminary findings facilitate further hypothesis generation and testing regarding this lake(s), this landscape, and their coevolution.
Quaternary Science Reviews, 2005
The dynamics of the late Wisconsin Lake Michigan Lobe of the Laurentide Ice Sheet, as interpreted by sediment-landform assemblages along its southeastern margin, are consistent with fast flow driven by high subglacial pore pressures. A major advance of the Lake Michigan Lobe terminated at the Kalamazoo Moraine, where proglacial glaciotectonic activity, marginal stagnation, and release of subglacial meltwater marked the extent of the advance. A large portion of the Valparaiso ''Moraine'', west of the Kalamazoo Moraine, is actually a drumlinized, till-capped upland plain rather than an ice-marginal landform assemblage. Lacustrine sediment, underlying the surficial diamicton in the Valparaiso upland, is glaciotectonically deformed to a depth of 10 m. The deformed interval consists of folded sandy and silty lacustrine sediment, which is in places sharply truncated by the overlying diamicton. Decoupling of the glacier from its bed is suggested by a discontinous thin bed of sand at the base of the diamicton, and by the sharp truncation of deformed lacustrine sediment. The association of drumlins, proglacial and subglacial deformation, marginal stagnation, and major ice-marginal outwash-fan deposition are indicative of fast flow, perhaps in a surge. These characteristics are consistent with a terrestrial ice-stream model for the Lake Michigan Lobe. r