Late Wisconsinan drift stratigraphy of the Saginaw Ice Lobe in south-central Michigan

Pollen and macrofossil evidence for the nature of the vegetation during glacial and interglacial periods in the regions south of the Wisconsinan ice margin is still very scarce. Modern opinions concerning these problems are therefore predominantly derived from geological evidence only or are extrapolated from pollen studies of late Wisconsinan deposits. Now for the first time pollen and macrofossil analyses are available from south-central Illinois covering the Holocene, the entire Wisconsinan, and most probably also Sangamonian and late Illinoian time. The cores studied came from three lakes, which originated as kettle holes in glacial drift of Illinoian age near Vandalia, Fayette County. The Wisconsinan ice sheet approached the sites from the the north to within about 60 km distance only.One of the profiles (Pittsburg Basin) probably reaches back to the late Illinoian (zone 1), which was characterized by forests with muchPicea. Zone 2, most likely of Sangamonian age, represents a period of species-rich deciduous forests, which must have been similar to the ones that thrive today south and southeast of the prairie peninsula. During the entire Wisconsinan (14C dates ranging from 38,000 to 21,000 BP) thermophilous deciduous trees likeQuercus, Carya, andUlmusoccurred in the region, although temporarily accompanied by tree genera with a more northerly modern distribution, such asPicea, which entered and then left south-central Illinois during the Woodfordian. Thus it is evident that arctic climatic conditions did not prevail in the lowlands of south-central Illinois (about 38°30′ lat) during the Wisconsinan, even at the time of the maximum glaciation, the Woodfordian. The Wisconsinan was, however, not a period of continuous forest. The pollen assemblages of zone 3 (Altonian) indicate prairie with stands of trees, and in zone 4 the relatively abundantArtemisiapollen indicates the existence of open vegetation and stands of deciduous trees,Picea, andPinus. True tundra may have existed north of the sites, but if so its pollen rain apparently is marked by pollen from nearby stands of trees. After the disappearance ofPinusandPiceaat about 14,000 BP (estimated!), there developed a mosaic of prairies and stands ofQuercus, Carya, and other deciduous tree genera (zone 5). This type of vegetation persisted until it was destroyed by cultivation during the 19th and 20th century. Major vegetational changes are not indicated in the pollen diagram for the late Wisconsinan and the Holocene.The dating of zones 1 and 2 is problematical because the sediments are beyond the14C range and because of the lack of stratigraphic evidence. The zones dated as Illinoian and Sangamonian could also represent just a Wisconsinan stadial and interstadial. This possibility, however, seems to be contradicted by the late glacial and interglacial character of the forest vegetation of that time.

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Late Wisconsinan ice-flow reconstruction for the central Great Lakes region

Canadian Journal of Earth Sciences ◽

10.1139/e85-097 ◽

1985 ◽

Vol 22 (6) ◽

pp. 935-940 ◽

Cited By ~ 6

Author(s):

Stephen Irving Dworkin ◽

Grahame J. Larson ◽

G. William Monaghan

Keyword(s):

Lake Michigan ◽

Source Area ◽

Heavy Mineral ◽

Lake Huron ◽

Georgian Bay ◽

South Central ◽

Mineral Assemblages ◽

Specific Source ◽

Late Wisconsinan ◽

Lake Michigan Lobe

Late Wisconsinan tills from the lower peninsula of Michigan can be differentiated with respect to the Lake Michigan, Saginaw, and Huron–Erie lobes on the basis of their heavy-mineral assemblages. Using discriminant analysis, the heavy-mineral assemblages can also be associated with specific source areas on the Canadian Shield. These associations suggest that (1) the Lake Michigan Lobe flowed southwestward across a region north of Lake Huron and then into southwestern Michigan; (2) the Saginaw Lobe flowed southwestward across a region northwest of Georgian Bay and then into south-central Michigan; and (3) the Huron–Erie Lobe flowed southwestward across a region north of Georgian Bay and then southward into southeastern Michigan.Comparison of the heavy-mineral assemblages of tills from southeastern Michigan with those from younger tills just south of Lake Huron indicates that a significant westward shift in source area occurred during the retreat of the Huron–Erie Lobe from southeastern Michigan.

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Radiocarbon Ages of Soils and Charcoal in Late Wisconsinan Loess, South-Central Nebraska

Quaternary Research ◽

10.1006/qres.1993.1006 ◽

1993 ◽

Vol 39 (1) ◽

pp. 55-58 ◽

Cited By ~ 24

Author(s):

David W. May ◽

Steven R. Holen

Keyword(s):

Organic Matter ◽

Great Plains ◽

Bulk Sample ◽

River Valley ◽

South Central ◽

Republican River ◽

Late Wisconsinan ◽

The U.S ◽

Bt Horizon

AbstractThe Farmdale Soil occurs below late Wisconsinan loess throughout the U.S. Midwest. At the La Sena site in the central Great Plains, humates in the Farmdale Interstadial Soil have a corrected age of 21,000 yr B.P. Humates in a buried Bt horizon and a bulk sample of overlying loess 2.5 m above the Farmdale Interstadial Soil have ages of 17,000 and 19,000 yr B.P., respectively. In the Republican River Valley Picea (spruce) charcoal is common in the lower meter of Peoria loess. Near Bloomington, Nebraska, humates from burned organic matter only 60 cm above the base of Peoria loess have a corrected age of ca. 19,000 yr B.P.

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Raised Shoreline Phenomena and Postglacial Emergence in South-Central Newfoundland

Géographie physique et Quaternaire ◽

10.7202/032475ar ◽

2007 ◽

Vol 36 (1-2) ◽

pp. 165-174 ◽

Cited By ~ 4

Author(s):

C. M. Tucker ◽

D. A. Leckie ◽

S. B. McCann

Keyword(s):

Sea Level ◽

Interglacial Period ◽

Last Interglacial ◽

Regional Pattern ◽

South Central ◽

Last Interglacial Period ◽

Late Wisconsinan ◽

Raised Beaches

ABSTRACT Two types of raised marine shoreline features occur in the Burin-Hermitage area of southern Newfoundland marine benches cut in bedrock, and terraces and beaches developed in unconsolidated materials. Most of the benches are older than Late Wisconsinan, and a horizontal rock shoreline at 4.5 ± 1.5 m, which occurs throughout the region, was probably formed in the last interglacial period. Raised deltas and coastal outwash deposits graded to former sea level positions, which define the Late Wisconsinan marine limit across the northern part of the study area, are correlated with terraces and raised beaches further south on the Burin Peninsula. The elevations of these features are used to define the regional pattern of postglacial emergence. More than 30 m of emergence has occurred in the northwest, but the extreme southern part of the region is undergoing submergence.

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Morphology and Composition of Two Late Wisconsinan Soils Forming in Till and Lacustrine Deposits, Scarborough Bluffs Area, South-Central Ontario

Géographie physique et Quaternaire ◽

10.7202/032611ar ◽

2007 ◽

Vol 39 (3) ◽

pp. 307-314 ◽

Cited By ~ 3

Author(s):

William C. Mahaney

Keyword(s):

Chemical Properties ◽

Parent Material ◽

Mineral Contents ◽

Parent Materials ◽

Lacustrine Deposits ◽

South Central ◽

Primary Mineral ◽

Physical Attributes ◽

Late Wisconsinan ◽

Sand And Gravel

ABSTRACT Halton Till and Glacial Lake Iroquois lacustrine sand and gravel deposits are the major surficial materials exposed at the surface of Scarborough Bluffs in South-Central Ontario. Luvisols formed in these deposits have different morphologies, including depth of weathering, complexity of horizonation, and strength of structural grades which result from parent material differences and pedogenesis. Particle size variations between the two paleosols result, in part, from different modes of deposition, and show that variable amounts of clay were produced pedogenically in the two systems. Clay mineral genesis, involving the transformation of illite and illitesmectite to vermiculite, appears to be restricted to the Iroquois sand paleosol, while some chloritization of illite occurs in both profiles. Changes in the primary mineral contents in the two paleosols suggest a similar magnitude of weathering in both systems. Distributions of vermiculite and dithionite-extractable Fe suggest some preweathering effects in the Halton Till paleosol. Morphological, mineralogical and some soil chemical properties are closely related to the physical attributes of the two different parent materials (till vs lacustrine sand and gravel).

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Late Wisconsinan glacial history in the Bonaparte Lake map area, south-central British Columbia: implications for glacial transport and mineral exploration1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.2Earth Sciences Sector Contribution Number: 20100093.

Canadian Journal of Earth Sciences ◽

10.1139/e10-100 ◽

2011 ◽

Vol 48 (6) ◽

pp. 1091-1111 ◽

Cited By ~ 16

Author(s):

A. Plouffe ◽

J.M. Bednarski ◽

C.A. Huscroft ◽

R.G. Anderson ◽

S.J. McCuaig

Keyword(s):

British Columbia ◽

Mountain Pine Beetle ◽

Mineral Exploration ◽

Source Region ◽

Mineralogical Composition ◽

Glacial History ◽

Ice Flow ◽

Glacial Sediments ◽

South Central ◽

Late Wisconsinan

This study is centred on the Bonaparte Lake map area located in the southern Interior Plateau of south-central British Columbia. The reconstruction of the Late Wisconsinan glacial history of this part of the southern sector of the Cordilleran Ice Sheet incorporates (i) the analysis and interpretation of landforms of various scales, (ii) the sedimentology and stratigraphy of glacial sediments, and (iii) the geochemical and mineralogical composition of till and analysis of regional glacial dispersal of these components. The onset of the last glacial event was initiated by ice advancing westerly and southwesterly into the study area from an alpine source region located in the Cariboo Mountains. As glaciation intensified, ice from the Coast Mountains coalesced with the Cariboo Mountain ice over the Interior Plateau and developed into an ice divide around 52° north latitude, which resulted in ice flow to be diverted to a southerly direction over the study area. The two dominant ice-flow directions produced palimpsest dispersal that was measured by three tracers in till including thorianite grains and terbium concentrations in the heavy mineral fraction, and granitoid pebble percentage. The two main phases of ice flow identified within our study area have significant implications for mineral exploration that uses mineral tracing in glacial sediments, especially in the area underlain by the highly prospective Quesnel Terrane.

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Timing and extent of Late Pleistocene glaciation in the Chugach Mountains, Alaska

Quaternary Research ◽

10.1017/qua.2020.106 ◽

2021 ◽

pp. 1-20

Author(s):

Joshua D. Valentino ◽

Lewis A. Owen ◽

James A. Spotila ◽

Jason M. Cesta ◽

Marc W. Caffee

Keyword(s):

Equilibrium Line Altitude ◽

Glacial Retreat ◽

Last Glacial Period ◽

Geomorphic Mapping ◽

Last Glacial ◽

South Central ◽

Reconstructed Temperature ◽

Late Wisconsinan ◽

Temperature Depression ◽

The Last Glacial

Abstract Geomorphic mapping, landform and sediment analysis, and cosmogenic 10Be and 36Cl ages from erratics, moraine boulders, and glacially polished bedrock help define the timing of the Wisconsinan glaciations in the Chugach Mountains of south-central Alaska. The maximum extent of glaciation in the Chugach Mountains during the last glacial period (marine isotope stages [MIS] 5d through 2) occurred at ~50 ka during MIS 3. In the Williwaw Lakes valley and Thompson Pass areas of the Chugach Mountains, moraines date to ~26.7 ± 2.4, 25.4 ± 2.4, 18.8 ± 1.6, 19.3 ± 1.7, and 17.3 ± 1.5 ka, representing times of glacial retreat. These data suggest that glaciers retreated later in the Chugach Mountain than in other regions of Alaska. Reconstructed equilibrium-line altitude depressions range from 400 to 430 m for late Wisconsinan glacial advances in the Chugach Mountains, representing a possible temperature depression of 2.1–2.3°C. These reconstructed temperature depressions suggest that climate was warmer in this part of Alaska than in many other regions throughout Alaska and elsewhere in the world during the global last glacial maximum.

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Depositional systems and seismic stratigraphy of a Quaternary basin: north Okanagan Valley, British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/e96-069 ◽

1996 ◽

Vol 33 (6) ◽

pp. 917-927 ◽

Cited By ~ 17

Author(s):

S. Vanderburgh ◽

M. C. Roberts

Keyword(s):

British Columbia ◽

Systems Approach ◽

Alluvial Fan ◽

Seismic Profiles ◽

The North ◽

South Central ◽

Depositional Systems ◽

Late Wisconsinan ◽

Okanagan Valley ◽

Basin Fill

Seismic and core data from north Okanagan Valley, a deep (~700 m of fill), elongate (~3 km wide by 45 km long) basin located in the Cordillera of south-central British Columbia, reveal a thick sequence of fine and coarse elastics. The architecture of the basin fill was delineated using 16 km of high-resolution, reflection seismic profiles, and 30 lithologic logs. Using a depositional systems approach, four systems were identified: subglacial fluvial, glaciolacustrine, alluvial fan, and channel. The subglacial fluvial system consists of a basal suite of compact, stratified to poorly stratified coarse clastics deposited beneath glacial ice under high hydrostatic pressure. Older sediments were almost completely excavated from the basin fill during periods of maximum subglacial flow during Late Wisconsinan glaciation. One of the outcomes of this study is that it lends support to the notion that Late Wisconsinan glaciers were capable of almost totally eroding older Pleistocene basin deposits while depositing thick sequences of subglacial fluvial sediments. During deglaciation, the basin was occupied by a lake in which laminated silt and clay were deposited (glaciolacustrine system). The wedge-shaped alluvial fan system interfingers with the finer clastics of the basin fill. Incised into the upper part of the basin fill are channel sediments forming the channel depositional system. Two stages in the evolution of the north Okanagan basin were identified: in the first stage (~10 ka), lake sediments were rapidly accumulating coeval with the formation of alluvial fans and fan deltas; the second stage shows the present-day architecture of the basin fill.

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CHRONOLOGY OF LATE WISCONSINAN LAURENTIDE ICE SHEET ADVANCE AND RETREAT NEAR ITS MAXIMUM LIMIT, SOUTH-CENTRAL INDIANA

10.1130/abs/2016nc-274951 ◽

2016 ◽

Author(s):

Henry M. Loope ◽

◽

Brandon Curry ◽

Thomas V. Lowell ◽

G. William Monaghan ◽

...

Keyword(s):

Ice Sheet ◽

Laurentide Ice Sheet ◽

South Central ◽

Late Wisconsinan ◽

Maximum Limit

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Evidence for recent groundwater flow through Late Wisconsinan till near Toronto, Ontario

Canadian Geotechnical Journal ◽

10.1139/t96-080-302 ◽

1996 ◽

Vol 33 (4) ◽

pp. 538-555 ◽

Cited By ~ 21

Author(s):

R E Gerber ◽

K WF Howard

Keyword(s):

Hydraulic Conductivity ◽

Pore Water ◽

Drilling Fluid ◽

Pore Waters ◽

Near Surface ◽

Degree Of Protection ◽

Core Samples ◽

South Central ◽

Vertical Hydraulic Conductivity ◽

Late Wisconsinan

The Northern till is a thick (~50 m) Late Winsconsinan diamict unit that occurs throughout south-central Ontario. The till has generally been regarded as massive and uniform, with a very low vertical hydraulic conductivity. It is similar to many other till units of mid-continental North American glaciated terrain in that it is believed to inhibit recharge to underlying aquifers and afford a high degree of protection to these aquifers from surface and near-surface sources of contamination. Standard methods of estimating hydraulic conductivity (K) for the Northern till, such as laboratory testing of core samples (other studies) and risingfalling head field piezometer tests (this study and other studies), characteristically yield values on the order of 1011 to 109 m/s. Typically, these values indicate advective traveltimes through the till on the order of hundreds to thousands of years. In contrast, isotopic evidence (2H, 18O, and 3H) from till pore waters indicates the presence of modern (post-1952) waters at depths of up to 50 m, suggesting either that certain facies of the till are considerably more permeable or that minor sand lenses or hydrogeologically active secondary permeability structures are locally important. In some areas, vertical flow velocities may approach 1 m/year. By comparing pore-water isotopic data from cores acquired using mud (sodium bentonite) and dry rotary methods, this study further demonstrates that representative pore-water samples can be obtained using a drilling fluid providing care is taken in preparing core samples for analysis. Key words: till, aquitard, permeability, recharge, contaminant transport, isotopes.

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