The Nipissing phase of ancestral Lakes Michigan, Huron, and Superior was the last pre-modern highstand of the upper Great Lakes. Reconstructions of past lake-level change and glacial isostatic adjustment (GIA), as well as activation and abandonment of outlets, is dependent on an understanding of the elevation of the lake at each outlet. More than 100 years of study has established the gross elevation of the Nipissing phase at each outlet, but the mixing of geomorphic and sedimentologic data has produced interpreted outlet elevations varying by at least several meters. Vibracore facies, optically stimulated luminescence and radiocarbon age control, and ground-penetrating radar transects from new and published studies were collected to determine peak Nipissing water-level elevations for the Port Huron (Lake Huron), Chicago (Lake Michigan), and Sault (Lake Superior) outlets. Contemporary elevations are 183.3, 182.1, and 195.7 m (International Great Lakes Datum of 1985 [IGLD85]), respectively. These data and published relative hydrographs were combined to produce one residual hydrograph for the Port Huron outlet that best defines the rise, peak, and rapid fall of the Nipissing phase from 6000–3500 calendar years ago. Establishing accurate elevations at the only present-day unregulated outlet of the Great Lakes and the only ancient outlet that has played a critical role in draining the upper Great Lakes since the middle Holocene is a critical step to better understand GIA and water-level change geologically and historically. The geologic context may provide the insight required for water managers to make informed decisions to best manage the largest freshwater system in the world.

Well-developed simple, stabilized parabolic dunes that are oriented to the east and southeast form the inland portion of a dune complex that extends ~32 km east-west across the southern shoreline of Lake Michigan in northwest Indiana. To better understand shoreline evolution during the Nipissing and post-Nipissing phases of Lake Michigan, subsurface sedimentology and radiocarbon ages from interdunal wetlands are considered with optical ages from nearby dunes within the landward portion of this area known as the Tolleston Beach. In the east, the once expansive Great Marsh had developed during the lake-level fall from the Nipissing peak (~4500 years ago). Units of eolian sand found within vibracores from the Great Marsh indicate that dunes formed and began migrating into the wetlands 4200–4400 years ago. In the west, newly formed dunes migrated along the shoreline while small interdunal wetlands formed shortly thereafter. Optical ages from two individual dunes indicate that this relict dune system stabilized by ~3500 years ago. Six samples collected from each of the two dunes yield optical ages that overlap at two standard errors. However, variations in individual ages detect episodic processes of sand movement that distinguish between the timing of landform migration and stabilization. Optical ages collected at the base of the slipface are interpreted as the age of landform stabilization. This study indicates that, with focused field-to-lab strategies, optical dating can provide a more robust chronology of shoreline development than previously considered; correlating eolian activity to wetland development and lake-level change in the Great Lakes.

Abstract Holocene sediments from three deep boreholes from Long Point, a 35-km-long sandy foreland on the Canadian side of eastern Lake Erie, display a consistent coarsening-upward trend from sheltered-water clays and silts to well-sorted shoreface sands. This trend persists in spite of the documented record of lake-level rise, due primarily to postglacial isostatic rebound of the Niagara River outlet. To resolve this contradiction within the context of shoreline evolutionary trends in eastern Lake Erie, sediment data from the boreholes are analyzed in combination with data from other sources. The analysis suggests that the sedimentary sequence is linked to the history of the Long Point foreland and its precursors. The resulting evolutionary model, supported by relict shore features, postulates that Long Point began as a north-south-trending cuspate peninsula, once linked to the ancestral Presque Isle spit on the United States side. The location of the feature was controlled by the Norfolk moraine, a cross-lake ridge of glacial origin. As lake levels rose, the foreland retreated northward with the shoreline as a whole, becoming smaller and more rounded but with well-developed recurves extending northeast. Around 5 to 4 ka, an abrupt rise in lake levels, related to resumption of drainage from the Nipissing Phase in the Upper Great Lakes into the Erie basin, resulted in inundation of most of the ancestral foreland. When the lake later fell to previous levels, presumably due to widening of the Niagara River outlet, the foreland commenced its present east-west orientation. At present, the distal portions of the spit are prograding southward, while the proximal areas are still retreating northward; in other words, the feature is slowly rotating clockwise. The pattern of landward retreat of parts of the foreland over sheltered (lagoonal) deposits and the rotation of the distal portions are also noted in the two other north-shore forelands. Point Pelee and Pointe-aux-Pins, and comparison is made with the transgressive marine barrier islands of the United States east coast.

Paleocurrents, facies, and thickness variations suggest that volcanic and sedimentary rocks of the lower Huronian succession accumulated in an easterly-trending fault-bounded trough. The upper Huronian, here taken to include the glaciogenic Gowganda Formation and younger Huronian units, is much more widespread and records deposition under conditions of more general downwarping of the crust. In the Lake Superior region, rocks of the Chocolay Group, which includes tillites and extensive orthoquartzites, are considered to be part of this depositional phase. Paleocurrents in both the Huronian Supergroup and Chocolay Group are generally eastward-directed during these two depositional phases. A strong deformational event next affected rocks of the Lake Huron region. This event is dated at about 2.1 Ga by contemporaneous intrusion of the Nipissing diabase. There is some evidence that much of the Huronian Supergroup was semilithified during this phase of deformation (McGregor phase). A similar tectonic episode may be recorded on the south shore of Lake Superior by intrusion of a porphyritic red granite about 2.0 Ga ago and by deformation and uplift of rocks of the Chocolay Group prior to deposition of the Menominee Group. The name Michigan phase is proposed for this event. In Minnesota, diabase dykes of similar age to the Nipissing diabase of Ontario were apparently intruded before deposition of the Menominee Group. The next depositional episode is characterised, in the Lake Superior region, by deposition of basal conglomerate and orthoquartzite followed by iron-formation. Equivalent rocks are not known in the Lake Huron region which may have been weakly emergent in the aftermath of the McGregor phase. In the Lake Superior region, the final phase of recorded early Proterozoic sedimentary history is represented by a succession of carbonaceous mudstones followed in a coarsening-upward sequence by turbidites. This phase may be represented in the Lake Huron area by mudstones and proximal turbidites of the Whitewater Group, preserved uniquely in the Sudbury Basin. Turbidites of the Whitewater Group were transported westward; there is some evidence of similar transport directions in the corresponding rocks in the Lake Superior region, but significant amounts of clastic detritus were drawn from the north and south margins of the basin. Subsequent deformation and low pressure, intermediate temperature metamorphism during the Penokean orogeny affected early Proterozoic rocks throughout the northern Great Lakes region. By analogy with other Proterozoic and Phanerozoic depositional basins, the sedimentary and tectonic history of early Proterozoic rocks of the northern Great Lakes area is tentatively interpreted in terms of the aulacogen model; a corollary of this interpretation is that the aulacogen opened into an ocean lying somewhere to the east, in the area now occupied by the Grenville province.

This study focuses on the geomorphology and geochronology of dunes formed on three sandy barrier systems at Clark, Europe and Kangaroo Lakes in Wisconsin's Door Peninsula. The Lake Michigan shoreline in the peninsula contains abundant evidence for fluctuations in lake level with paleo-shoreline features that lie up to ~7 m above the present shoreline. Dunes are not very common along the Lake Michigan shoreline in Wisconsin, but the three bay barriers studied contain beach ridges that were buried by varying depths of eolian sand in the form of low relief sandsheets as well as parabolic and transverse dunes that have relief of up to 21 m. The purpose of this study was to document when the barriers formed and when the subsequent eolian activity occurred. The chronology presented here for barrier emplacement and dune development is based on 65 optically stimulated luminescence (OSL) samples which were collected from littoral sediment in the barriers (n = 17) and the overlying eolian sand (n = 48). Sediment samples were collected using bucket augers or a vibracoring device at depths ranging from 0.5 to 4.1 m below the ground surface. The OSL ages show that barriers in each of the study sites were constructed between ~5.9 and 3.9 ka, corresponding closely to the Nipissing high lake phase. OSL ages falling between 3.3 and 2.5 ka at the Kangaroo Lake site suggest the portion of the barrier closest to Lake Michigan formed during the Algoma phase. The majority of the eolian ages fall into two primary groups that overlap with or are slightly younger than the ages acquired from the barriers. These results suggest eolian activity ended between 4.5 and 3.7 (n = 20 ages) and 2.5 and 1.8 (n = 11 ages) ka. Both geomorphic and geochronological evidence suggests that dune development occurred rapidly when sand supply increased as lake levels fell following these two transgressive events.

Strandlines and related features representing former high glacial-lake levels possibly related to the Glenwood and Calumet phases of glacial Lake Chicago were identified from Oceana County north to Benzie County in the northwestern lower peninsula of Michigan. Lacustrine features occur as far as 25 km inland from the Lake Michigan shore at altitudes above the rebounded water planes of glacial Lake Algonquin and the Nipissing Great Lakes identified by earlier investigators. In order to determine if the water planes identified in this study and those of previous investigators represent the Glenwood and/or Calumet phases, water-plane altitudes are compared with a height/distance curve for the highest level of the Lake Algonquin water plane constructed by J. W. Goldthwait. The Goldthwait curve north of his zero isobase indicates the nature of glacial isostasy for the northern Lake Michigan basin following the development of the Glenwood and Calumet phases. The rebounded water planes of both the Glenwood and Calumet phases should follow exponential curves similar to that of Lake Algonquin but at higher altitudes. The water-plane data were projected onto a vertical plane oriented perpendicular to Goldthwait’s Lake Algonquin isobases in the northern part of the Lake Michigan basin and parallel to the axis of Lake Michigan in the southern part of the basin. From Ludington north to Frankfort, Michigan, the array of water-plane altitudes is diffuse but has an upper boundary that corresponds to a theoretical Glenwood II water plane. Only two sites occur at elevations high enough to be attributed to a Glenwood I water plane. Lacustrine features that occur at lower altitudes within the array, but above the Algonquin level, are within range of a theoretical Calumet water plane. Correlation of water-plane data with either the Glenwood or Calumet phase will probably remain unclear until ages are determined for many of the features.

The types and spatial distribution of subsurface sedimentary deposits in the Calumet and Toleston Beaches of ancestral Lake Michigan were studied to better understand the evolution of the southeastern shore of Lake Michigan. Deposits of eight depositional environments were recognized: (1) dune, (2) foreshore, (3) upper shoreface, (4) lower shoreface, (5) offshore, (6) back-barrier lacustrine, (7) paludal, and (8) glacigenic. The Calumet Beach formed at the end of a rise in lake level following the Two Creeks phase, a time period of low lake level in the Lake Michigan basin, to the Calumet level. This trasgressive event was primarily erosional and produced a ravinement throughout the study area. Locally, however, relief on the underlying till of the Lake Border Moraine was instrumental in the preservation of nearshore sediments. Progradation of the Calumet shoreline produced a vertical stacking of shallow-water coastal sediments over deeper water deposits. Lakeward translation of the shoreline occurred for an unknown period of time, until the altitude of the lake dropped to the level of the Chippewa phase of ancestral Lake Michigan. Unlike the transgression from the Two Creeks level to the Calumet level, the post-Chippewa transgression to the Nipissing I level was dominantly depositional. This transgressive event is recorded in an ascending sequence of back-barrier lacustrine, dune, and foreshore deposits in the western part of the study area and by the onlap of the toe of the Calumet dune and beach complex by back-barrier lacustrine, palustrine, and dune sediments.

Abstract Lake Michigan is the world’s sixth largest freshwater lake and has many features in common with oceanic settings, albeit at a smaller scale. All of the constructional features typical of ocean coasts can be found along the shore of Lake Michigan, and it has a shelf-slope system where coastwise rectification of currents, coastal downwelling jets, Coriolis veering of lake currents, benthic nepheloid layer, and density currents have been observed. Unlike ocean coasts, however, the wave climate is predominantly mild, and only a very small lunar tide exists, although other (quasi) periodic water-level fluctuations such as seiches and edge waves do occur. Another significant difference is the occurrence of quasicyclical climatically induced lake-level fluctuations of as much as 2 m (6.6 ft) that greatly influence the way that coastal sediments accumulate. Lastly, the Lake Michigan coast during the late Wisconsin and Holocene experienced multiple noncyclic transgressive and regressive events. Lake levels have been as much as 18 m (60 ft) higher and 60 m (200 ft), or more, lower than present, and changes have commonly occurred at rates several magnitudes greater than the most rapid eustatic sea level changes. In this chapter, we will show how hydrodynamic processes, cyclic and noncyclic lake-level changes, and the way in which sediments are supplied to the lake have interacted to shape the architecture of sedimentary deposits along the coast and in the deep basins. We will summarize the results of our own work, but we are also indebted to many researchers whose work is included in this narrative.