Alan F. Arbogast

Reconstructing the geomorphic evolution of large coastal dunes along the southeastern shore of Lake Michigan

Abstract Coastal dunes are common along the eastern shore of Lake Michigan, with the most common being large (>30 m high), parabolic dunes that mantle lake terraces south of Manistee, MI. Although these dunes are an important resource in Michigan, and thus intensely managed by various state agencies, their geomorphic history is poorly understood. This study examines four sites near Holland, MI, through stratigraphic and radiocarbon analyses and is the most detailed geomorphic reconstruction conducted of coastal parabolic dunes in the region. Results from this study could benefit the environmental agencies in their management of the coastal dune ecosystem. Deposition of Eolian sand apparently began ∼5500 cal. years BP (i.e., during the Nipissing high stand). Most (∼75%) dune building occurred between ∼4000 and 2500 cal. years BP but was punctuated by brief periods of stability that resulted in the development of Entisols (A/C horizonation). Entisol burial occurred because the sand supply apparently increased during both the receding and rising lake levels. Subsequently, each dune stabilized for ∼2000 years, allowing the formation of Inceptisols (i.e., A/E/Bs/C horizonation). This interval of dune stability correlates with sites south of Holland and occurred while Lake Michigan fluctuated slowly and the beach potentially prograded. These combined variables of slow fluctuation and potential beach progradation hypothetically protected the dunes from wave erosion. Dunes near Holland became active again ∼1000–500 cal. years BP and grew both vertically and laterally. This activity intensified in the past 500 cal. years BP and hypothetically occurred due to recession of the lake shore such that wave erosion at the modern bluff base resumed. Results from this study indicate that coastal dunes along Lake Michigan are similar to many coastal dunes around the world, including those along the intermediate beaches in SE Australia.

Late‐Quaternary Landscape Response to Environmental Change in South‐Central Kansas

The central Great Plains is an excellent place to study late-Quaternary geomorphic responses to climatic fluctuations because the landscape is easily disturbed and deposits contain abundant paleoenvironmental information. Although much research has already been conducted, studies are needed that correlate a variety of geomorphic responses to environmental change at specific sites. This paper presents a paleoenvironmental and geomorphic reconstruction for the Great Bend Sand Prairie, a mosaic of sand sheets and dune fields in south-central Kansas. Results indicate that two stratigraphic units dominate the upland geology. Late-Wisconsin deposits consist of poorly sorted sand, silt, and clay that probably accumulated in a low-energy fluvial environment. Eolian deposition of loess also occurred, but most silt was integrated with the alluvium. Intact deposits of loess are widely scattered. All sediments contain well developed soils, indicating extended surface stability. Macrofossil and isotopic (δ13C) evidenc...

Maximum-limiting ages of Lake Michigan coastal dunes: Their correlation with Holocene lake level history

Coastal geomorphology along the Great Lakes has long been linked with lake-level history. Some of the most spectacular landforms along the eastern shore of Lake Michigan are high-relief dunes that mantle lake terraces. It has been assumed that these dunes developed during the Nipissing high stand of ancestral Lake Michigan. This hypothesis was tested through stratigraphic analyses and radiocarbon dating of buried soils at four sites between Manistee and Grand Haven, Michigan. At each site, thick deposits of eolian sand overlie late-Pleistocene lacustrine sands. Moderately developed Spodosols (Entic Haplorthods) formed in the uppermost part of the lake sediments are buried by thick dune sand at three sites. At the fourth locality, a similar soil occurs in a very thin (1.3 m) unit of eolian sand buried deep within a dune. These soils indicate long-term (∼ 4,000 years) stability of the lake deposits following subaerial exposure. Radiocarbon dating of charcoal in the buried sola indicates massive dune construction began between 4,900 and 4,500 cal. yr B.P. at the Nordhouse Dunes site, between 4,300 and 3,900 cal. yr B.P. at the Jackson and Nugent Quarries, and between 3,300 to 2,900 cal. yr B.P. at Rosy Mound. Given these ages, it can be concluded that dune building at one site occurred during the Nipissing high stand but that the other dunes developed later. Although lake levels generally fell after the Nipissing, it appears that dune construction may have resulted from small increases in lake level and destabilization of lake-terrace bluffs.

Widespread middle Holocene dune formation in the eastern Upper Peninsula of Michigan and the relationship to climate and outlet-controlled lake level

Dating of five widely spaced (noncoastal) dunes in eastern upper Michigan by optically stimulated luminescence of quartz establishes that eolian sand was last mobilized between ca. 7 and 5.5 ka in the region. Although this interval corresponds to the drier Altithermal- Hypsithermal period, climate alone may not have been sufficiently arid to cause dune formation in this area. Instead, it appears that dune formation may also be linked to depressed water tables, associated with outlet-controlled low levels in Lakes Michigan and Superior. Following dune stabilization, peat began to accumulate in interdune areas ca. 4.4 ka.

CONCURRENT STABILIZATION OF SOME INTERIOR DUNE FIELDS IN MICHIGAN

Inland dunes occur over a large part of east-central lower Michigan, where they mantle glaciolacustrine and outwash surfaces that were exposed around 12,000 yrs. B.P. The dunes are parabolic, with northwest-oriented limbs, and occur in swampy landscapes, suggesting that paleoclimatic conditions at the time of their formation were much drier and possibly windier. In order to determine whether the dunes stabilized concurrently or randomly in time and space, surface soils were studied on 30 dunes in the area and quantitatively analyzed for relative differences. Soils data from the dunes indicate concurrent stabilization, following a period of regional mobilization of aeolian sand. Surface soils have formed by podzolization, in uniform parent materials, and are morphologically similar throughout the area. All the soils are weakly developed, with subtle variations on a A-E-Bs-BC-C horizonation sequence. Munsell colors of Bs horizons are remarkably uniform, with 27 of 30 sites exhibiting values of 4 and chromas...

Post-Nipissing Origin of a Backdune Complex along the Southeastern Shore of Lake Michigan

Relatively low (<25 m) parabolic dunes and dune ridges occur inland of massive parabolic dunes in many dune complexes along the southeastern shore of Lake Michigan. The major study of these backdunes (Tagues, 1946) concluded, based on field criteria, that they were older than the massive parabolic dunes and originate at the Calumet and Algonquin stages of ancestral Lake Michigan (~14-10 ka). Younger ages are indicated by this study in which Optically Stimulated Luminescense (OSL) ages were obtained from the crest of three backdunes southwest of Holland, Michigan. All ages are within statistical error of each other and indicate dune stabilization at ~4 ka. Similarities in surface soil development throughout the backdunes support the conclusion that they all stabilized at about the same time. Radiocarbon ages from paleosols indicate that the massive parabolic dunes were active at 4 ka and that this activity persisted after the back dunes had stabilized. In the Holland area, dune growth and migration occurred in a broad zone, including both back and massive parabolic dunes, immediately after the rise to and drop from Nipissing II high lake levels but became confined to a narrower zone closer to shore after ~4 ka.

Estimating the Time Since Final Stabilization of a Perched Dune Field Along Lake Superior

The Nodaway dune field is perched along Lake Superior in Upper Michigan. This study uses absolute and relative-age dating methods to test the hypothesis that the dune field finally stabilized after the Nipissing high stand, about 4,000 years ago. Surface soils on snouts of all dunes are moderately developed Spodosols, indicating that dunes stabilized within a few hundred years of each other. One thermoluminescence date provided an age of 8 ka from soil parent material, but is probably overestimated due to residual thermoluminescence. Subsequent optical stimulated luminescence and accelerator mass spectrometry age estimates indicate that the most recent accumulation of sand occurred between ˜3.7 and 3.0 ka. This interval suggests one of three possibilities: 1) that the dune field was reactivated during the Algoma high stand and then stabilized; 2) that the dune field stabilized gradually, probably as sand supply diminished after the Nipissing high stand; and 3) that a combination of these two processes occurred.

AGE ESTIMATES OF INLAND DUNES IN EAST-CENTRAL LOWER MICHIGAN USING SOILS DATA

Extensive deposits of eolian sand occur deep (>50 km) within the interior of east-central lower Michigan. These dunes are most common in the Saginaw lowland where they are parabolic, with limbs oriented northwesterly. Their presence on densely forested landscapes indicates that paleoenvironmental conditions differed sufficiently for dune formation to have occurred. In a previous study, Arbogast et al. (1997) illustrated that surface soils in the northwestern part of the Saginaw dune field were morphologically similar, consisting of weakly developed Spodosols (A/E/Bs/C horizonation). Thus, these dunes must have stabilized concurrently following regional mobilization of eolian sand. In this study, we present soils data from dunes in the southeastern part of the Saginaw dune field. Surface soils were analyzed at 19 sites in the Deford State Game Area in Tuscola County. Morphologically, the soils within the Deford area are similar (A/E/Bs/C horizonation), indicating that Deford dunes stabilized concurrently. ...

LATE QUATERNARY EVOLUTION OF A LUNETTE IN THE CENTRAL GREAT PLAINS: WILSON RIDGE, KANSAS

Lunettes are aeolian dunes that form on the downwind margins of playas. Although common on the Southern High Plains and elsewhere, they are poorly understood. Geomorphic and stratigraphic investigations at Wilson Ridge in the central Great Plains of Kansas reveal a complex late Quaternary history, with episodic deflation of the playa and sedimentation on the lakes southern margin. Ten stratigraphic units are present, five of late Wisconsinan age and five related to Holocene events. Woodfordian deposits consist of silt and fine sand containing crushed gastropods. Late Wisconsinan sedimentation was interrupted when a well-developed soil formed around 17,000 yr B.P., a period of high water in the playa. Pleistocene and Holocene deposits are separated by another well-developed paleosol on the south side of the dune and by an unconformity on the north slope. Although Holocene sediments are texturally similar to older deposits, they lack gastropods, suggesting arid conditions in the playa. Early Holocene insta...

Developing Online Geography Courses: Experiences from Michigan State University.

Abstract During academic year 1999–2000, the Geography Department at Michigan State University (MSU) launched a program of online geography courses. Since then, four undergraduate online geography courses have been collectively developed and delivered to over 4,500 domestic and international students in association with MSUs Virtual University Design and Technology (vuDAT). The creation of each virtual course has taught valuable lessons concerning course development and administration; interactions with students have shed insight on course structure, content, and instruction. This article addresses development, management, and pedagogic concerns pertinent to the operation of online geography courses and offers suggestions to others who wish to develop online courses. Preliminary evidence on the effectiveness of these courses is also presented.