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In this paper we introduce the term 'loess pyramid' for an unusual form of relief in thick loess deposits. From a distance, the loess pyramid resembles a haystack; this is why it is known as 'the haystack' by the local residents. Its erosional origin is conditional, occurring only where loess deposits are thick and gully erosion changes direction significantly. We describe a loess pyramid on a thick loess section near the Tisa (Tisza) River in Titel province, Serbia. The pyramid has a maximum altitude of 111.6 m, a width of 82 m and a length of 52 m. It is framed by two smaller gullies that belong to one hydrological system, but each has different morphological properties. The gullies output directly to the floodplain of the Tisa River, which cut the escarpment that the pyramid is set within. Given the relatively small number of references from the international and geomorphological literature on such landforms, this study represents an interesting contribution to the geomorphology of loess landscapes.

We introduce, characterize, and interpret the geomorphic history of a relict, Pleistocene-aged delta of the Chippewa River in central Lower Michigan. The broad, sandy Chippewa delta developed into various stages of Glacial Lake Saginaw, between ca. ≈ 17 and 15 ka·BP (calibrated ages). Although the delta was first identified in 1955 on a statewide glacial geology map, neither its extent nor its Pleistocene history had been previously determined. The delta is typically forested, owing to its wet, sandy soils, which stand out against the agricultural fields of the surrounding, loamy lake plain sediments. The delta heads near the city of Mt Pleasant and extends eastward onto the Saginaw Lowlands, i.e., the plain of Glacial Lake Saginaw. Data from 3285 water well logs, 180 hand augered sites, and 185 points randomly located in a GIS on two-storied (sand over loam) soils were used to determine the extent, textural properties, and thickness of the delta. The delta is ≈ 18 km wide and ≈ 38 km long and is sandy throughout. Deltaic sediments from neighboring rivers that also drained into Glacial Lake Saginaw merge with the lower Chippewa delta, obscuring its boundary there. The delta is thickest near the delta's head and in the center, but thins to 1–2 m or less on its eastern margins. Mean thicknesses are 2.3–2.9 m, suggestive of a thin sediment body, frequently impacted by the waves and fluctuating waters of the lakes. Although beach ridges are only weakly expressed across the delta because of the sandy sediment, the coarsest parts of the delta are generally coincident with some of these inferred former shorezones and have a broad, incised channel that formed while lake levels were low. The thick upper delta generally lies above the relict shorelines of Glacial Lakes Saginaw and Arkona (≈ 17.1 to ≈ 16 ka·BP), whereas most of the thin, distal delta is associated with Glacial Lake Warren (≈ 15 ka·BP). Together, these data suggest that the Chippewa delta formed and prograded as lake levels in the Saginaw Lowlands alternated and episodically fell. The result is a delta that is comparatively thin, expansive, and sandy. In some places, these sands have subsequently been reworked into fields of small parabolic dunes. [ABSTRACT FROM AUTHOR]

Hillslope position has long been important in soil geomorphology. At the scale of county-level soil maps, more soil boundaries are based on topography than any other soil-forming factor. However, the inability to accurately delineate topographic breaks across hillslope--either due to lack of sufficient topographic resolution or the proper technology to develop and/or model them--hinders soil mapping efforts. In this research, we developed a decision tree model for classifying hillslope position, which was calibrated and validated using the observations of soil scientists in the field. Different decision tree structures were tested with classification breaks based on calibration groups' mean midpoints, median midpoints, and fuzzy membership. The final model objectively and quantitatively classifies the five major hillslope positions and performs well on different landscapes, making it suitable for efficient application to large areal extents. The resulting maps of hillslope position represent base maps that can be used to (i) improve research on toposequences by providing explicit definitions of each hillslope element's location, (ii) facilitate the disaggregation of soil map unit complexes, and (iii) identify map unit inclusions that occur due to subtle topographic variation. Base maps developed by the model can also help identify areas of possible inaccuracies in soil maps, especially where soil boundaries cross topographic breaks. Predictions from the model enable the mapper to better place soil map unit boundaries at locations where defendable landscape breaks exist. [ABSTRACT FROM AUTHOR]

Abstract: We present textural and thickness data on loess from 125 upland sites in west-central Wisconsin, which confirm that most of this loess was derived from the sandy outwash surfaces of the Chippewa River and its tributaries, which drained the Chippewa Lobe of the Laurentide front during the Wisconsin glaciation (MIS 2). On bedrock uplands southeast of the widest outwash surfaces in the Chippewa River valley, this loess attains thicknesses >5m. OSL ages on this loess constrain the advance of the Laurentide ice from the Lake Superior basin and into west-central Wisconsin, at which time its meltwater started flowing down the Chippewa drainage. The oldest MAR OSL age, 23.8ka, from basal loess on bedrock, agrees with the established, but otherwise weakly constrained, regional glacial chronology. Basal ages from four other sites range from 13.2 to 18.5ka, pointing to the likelihood that these sites remained geomorphically unstable and did not accumulate loess until considerably later in the loess depositional interval. Other OSL ages from this loess, taken higher in the stratigraphic column but below the depth of pedoturbation, range to nearly 13ka, suggesting that the Chippewa River valley may have remained a loess source for several millennia. [Copyright &y& Elsevier]

This paper provides the complete list of papers that were read and discussed in graduate seminars run in 1998 and 2001 by Professor Donald Johnson of the University of Illinois. A literature sleuth, Professor Johnson’s courses provide insight into what he thought were the major papers and books that helped guide and advance the fields of soil geomorphology in particular, and geomorphology in general. To his list I have taken the liberty of adding some papers that he either missed or was too modest to include, i.e. some of his own! Delving into the deep literature is hard work. I hope that this paper shows the appreciation that I have for the effort that Professor Johnson put into this task, over many years. In this era of rapid knowledge and literature expansion, it is also my hope that this list helps budding (and seasoned) geomorphologists to delve into the classic literature. [ABSTRACT FROM AUTHOR]

Abstract: We present the first study of the distribution, genesis and paleoenvironmental significance of late Pleistocene loess in northeastern Wisconsin and adjacent parts of Michigan''s Upper Peninsula. Loess here is commonly 25–70cm thick. Upland areas that were deglaciated early and remained geomorphically stable preferentially accumulated loess by providing sites that were efficient at trapping and retaining eolian sediment. Data from 419 such sites indicate that the loess was mainly derived from proglacial outwash plains and, to a lesser extent, hummocky end moraines within and near the region, particularly those toward the east of the loess deposits. Most of the loess was transported on katabatic winds coming off the ice sheet, which entrained and transported both silt and fine sands. The loess fines markedly, and is better sorted, distal to these source regions. Only minimal amounts of loess were deposited in this area via westerly winds. This research (1) reinforces the observation that outwash plains and end moraines can be significant loess sources, (2) provides evidence for katabatic winds as significant eolian transport vectors, and (3) demonstrates that the loess record may be variously preserved across landscapes, depending on where and when geomorphically stable sites became available for loess accumulation. [Copyright &y& Elsevier]

Many important geomorphic and ecological attributes center on soil water content, especially over long timescales. In this paper we present an ordinally based index, intended to generally reflect the amount of water that a soil supplies to plants under natural conditions, over long timescales. The Natural Soil Drainage Index (DI) ranges from o for the driest soils (e.g., those shallow to bedrock in a desert) to 99 (open water). The Dl is primarily derived from a soil's taxonomic subgroup classification, which is a reflection of its long-term wetness. Because the Dl assumes that soils in drier climates and with deeper water tables have less plant-useable water, taxonomic indicators such as soil moisture regime and natural drainage class figure prominently in the "base" DI formulation. Additional factors that can impact soil water content, quality, and/or availability (e.g., texture), when also reflected in taxonomy, are quantified and added to or subtracted from the base DI to arrive at a final Dl value. In GIS applications, map unit slope gradient can be added as an additional variable. The index has myriad applications in forestry, ecology, geomorphology, and environmental modeling, especially when examined spatially; we provide some examples in this paper. The DI has great potential for many landscape-scale modeling and GIS applications where soil water content is an important variable. DI values for all soils currently classified by the NRCS can be accessed from pull-down menus on the DI web site: http://www.drainageindex.msu.edu/. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents textural, geochemical, mineralogical, soils, and geomorphic data on the sediments of the Grayling Fingers region of northern Lower Michigan. The Fingers are mainly comprised of glaciofluvial sediment, capped by sandy till. The focus of this research is a thin silty cap that overlies the till and outwash; data presented here suggest that it is local-source loess, derived from the Port Huron outwash plain and its down-river extension, the Mainstee River valley. The silt is geochemically and texturally unlike the glacial sediments that underlie it and is located only on the flattest parts of the Finger uplands and in the bottoms of upland, dry kettles. On sloping sites, the silty cap is absent. The silt was probably deposited on the Fingers during the Port Huron meltwater event; a loess deposit roughly 90 km down the Manistee River valley has a comparable origin. Data suggest that the loess was only able to persist on upland surfaces that were either closed depressions (currently, dry kettles) or flat because of erosion during and after loess deposition. Deep, low-order tributary gullies (almost ubiquitous on Finger sideslopes) could only have formed by runoff, and soil data from them confirm that the end of gully formation (and hence, the end of runoff) was contemporaneous with the stabilization of the outwash surfaces in the lowlands. Therefore, runoff from the Finger uplands during the loess depositional event is the likely reason for the absence of loess at sites in the Fingers. Because of the sandy nature and high permeability of the Fingers'' sediments, runoff on this scale could only have occurred under frozen ground conditions. Frozen ground and windy conditions in the Fingers at the time of the Port Huron advance is likely because the area would have been surrounded by ice on roughly three sides. This research (1) shows that outwash plains and meltwater streams of only medium size can be significant loess sources and (2) is the first to present evidence for frozen ground conditions in this part of the upper Midwest. [Copyright &y& Elsevier]

Two Woodfordian glaciated regions in Wisconsin were analyzed to determine the impact of variable loess thickness and contrasting till texture on soil pattern and landscape properties. Each region consisted of a ground moraine/end moraine/outwash plain landform sequence. Data were compiled from soil and topographic maps. In addition to using standard methods of soilscape analysis. I used a natural soil drainage index, calculated from taxonomic data, to determine regional variability and pattern of soil wetness. Results indicate that soilscape variation within each region was large. There were no statistically significant differences, therefore, that could be attributed to known soil- forming processes or to parent material variability. Stratifying the data by geomorphic subregion rather than by region reduced the within-unit soil variability and resulted in numerous significant soilscape differences between subregions. The implication is that soilscape variability is large at the regional scale but converges rapidly with decreasing size of study area. [ABSTRACT FROM AUTHOR]