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We present data on molluscan fauna within the L3 loess unit (and partially within the S3 paleosol) from the key loess section of Veliki Surduk in Serbia. The section correlates to Marine Isotope Stage (MIS) 8 and late MIS 9 and, thus, spans the time frame from ~350 to 250 ka. The Veliki Surduk loess–paleosol sequence (LPS) is located on the northwestern margin of the Titel loess plateau and comprises ~30 m of sediments. Our focus is on a 5.4 m thick sedimentary interval, which was sampled at 20 cm increments, each sample covering approximately 2 ky. Nine mollusk species were identified in the loess sequence: Granaria frumentum, Helicopsis striata, Pupilla triplicata, Chondrula tridens, Pupilla muscorum, Succinella oblonga, Punctum pygmaeum, Vallonia costata, and Vitrina pellucida, as well as a few unidentified slug taxa (Limacidae, Agriolimacidae, and Milacidae). The majority of the snail assemblage occurs at the transition between MIS 9 and MIS 8, suggesting a mostly dry climate and an open and steppe-like habitat. The fauna identified in the upper part of the paleosol layer S3, below the L3 unit, indicated aridification. [ABSTRACT FROM AUTHOR]

We report on pollen, plant macrofossils, and associated lithostratigraphy of a sediment core extracted from the base of Silver Lake, a kettle lake in northern Lower Michigan, USA, which reveal a complex deglacial scenario for ice block melting and lake formation, and subsequent plant colonization. Complementary multivariate statistical and squared chord distance analyses of the pollen data support these interpretations. The basal radiocarbon age from the core (17 540 cal years BP) is rejected as being anomalously old, based on biostratigraphic anomalies in the core and the date's incongruity with respect to the accepted regional deglaciation chronology. We reason that this erroneous age estimate resulted from the redeposition of middle-Wisconsin-age fossils by the ice sheet, mixed with the remains of plants that existed as the kettle lake formed at ca. 10 940 cal years BP by ice block ablation. Thereafter, the kettle lake became a reliable repository of Holocene-age fossils, documenting a mature boreal forest that existed until 10 640 cal years BP, followed by a pine-dominated mixed forest, an early variant of the mixed conifer-hardwood forest that persists to the present day. Our study demonstrates that researchers investigating kettle lakes, a common depositional archive for plant fossils in deglaciated landscapes, should exercise caution in interpreting the basal (Late Pleistocene/early Holocene-age) part of lake sediment cores. Key words: deglaciation, Holocene, kettle lakes, Michigan, pollen, radiocarbon dating. Nous rendons compte des pollens, des macrofossiles de plantes et de la lithostratigraphie associee d'une carotte de sediments extraite de la base du lac Silver, un lac de kettle situe dans le nord du bas Michigan (Etats-Unis), qui revelent un scenario de deglaciation complexe pour la fonte de blocs de glace et la formation de lacs, et la colonisation subsequente par des plantes. Des analyses statistiques multivariables et du carre de la distance de cordes complementaires des donnees sur le pollen appuient ces interpretations. L'age au carbone radioactif basal obtenu pour la carotte (17 540 a etal. BP) est rejete parce qu'il est anormalement vieux, a la lumiere d'anomalies biostratigraphiques dans la carotte et de l'incongruite de cet age par rapport a la chronologie de deglaciation regionale acceptee. Nous interpretons cet age estime errone comme etant le resultat du re-depot de fossiles d'age wisconsinien moyen par l'inlandsis, melanges aux restes de plantes qui existaient au moment de la formation du lac de kettle vers 10 940 a etal. BP par ablation de blocs de glace. Par la suite, le lac de kettle est devenu un centre de depot fiable de fossiles d'age holocene, qui documentent la foret boreale mature qui existait jusqu'a 10 640 a etal. BP, suivie d'une foret mixte dominee par les pins, une variante precoce de la foret mixte a coniferes et feuillus qui persiste a ce jour. L'etude demontre que les chercheurs qui etudient les lacs de kettle, une archive repandue de fossiles de plantes dans des paysages de deglaciation, devraient faire preuve de prudence dans l'interpretation de la partie basale (d'age pleistocene tardif a holocene precoce) de carottes de sediments de lac. [Traduit par la Redaction] Mots-cles : deglaciation, Holocene, lacs de kettle, Michigan, pollen, datation au carbone radioactif., Introduction Researchers are becoming increasingly aware of the challenges and intricacies of reconstructing terminal Pleistocene environments, including elucidating the timing of deglaciation events and the stages of landscape evolution at [...]

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.

Large parts of the upper Midwest, USA were impacted by permafrost during the Last Glacial Maximum (LGM). Even though permafrost persisted as the Laurentide Ice Sheet began to recede, direct age control of this interval is largely lacking. To better temporally constrain the permafrost interval in western Wisconsin, we identified two sites, outside the Late Wisconsin (MIS 2) glacial limit, that contain relict, ice‐wedge pseudomorphs, initially interpreted to be sand wedges, hosted within well‐drained outwash deposits. The pre‐Wisconsin (>MIS 5) host material commonly displays up‐turned bedding near the contact with the wedges, indicative of well‐formed features. The wedges are filled with well‐sorted, gravel‐free, medium and fine sands, and lack evidence of post‐formational disturbance, pointing to an aeolian sand infill and confirming them as sand wedges. Ventifacts on nearby uplands attest to windy conditions here in the past. Optically stimulated luminescence (OSL) ages on five sand wedges indicate that they filled with sand between c. 19.3 and 18.3 ka at the southerly site and between c. 15.1 and 14.7 ka at the northerly site, which is closer to the LGM margin. Sand wedges at the latter site were wider and had more complex morphologies, possibly suggesting a longer interval of formation and/or more intense permafrost. We also examined a site along a ridge crest, between the two wedge sites, which displayed interbedded loess and sand, dated by OSL to 12.7 ka. Together, these results point to dry, cold, windy conditions in west‐central Wisconsin, within 100 km of the LGM limit. At this time, aeolian sands were being transported across a landscape with (at least scattered) permafrost. The OSL results suggest multiple phases, or perhaps time‐transgressive, sand‐wedge formation, associated with permafrost between c. 19 and 15 ka, with dry, windy (and likely, cold) conditions persisting until at least 12.7 ka. [ABSTRACT FROM AUTHOR]

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1467-8306.2006.00517.x Byline: Randall J. Schaetzl (*), Sharon Anderson (*) Keywords: pedology; soil genesis; soil geomorphology Author Affiliation: (*)Department of Geography, University of Wisconsin-Madison