Pleistocene periglacial activity in eastern Australia was widespread and has been predicted to have extended along much of the east coast. This paper describes block deposits in the New England Tablelands, Australia, as far north as 30°S. These deposits are characterized by openwork blocks on slopes below the angle of repose. The deposits are positioned where frost cracking was significant and range in area up to 8 ha. Surface exposure dating using the cosmogenic nuclide 36Cl from four block deposits indicate all sites were active late during the last glacial cycle, with a concentration of activity between 15–30 ka. Modern temperature measurements from block deposits highlight the importance of local topography for promoting freezing. Periglacial deposits are likely to have been more extensive than previously recognized at these northern limits, and mean annual temperature more than 8°C colder than today.

Surface exposure dating was applied to erosional shorelines associated with the Angliers lake level that marks an important stage of Lake Ojibway. The distribution of 15 10Be ages from five sites shows a main group (10 samples) of coherent 10Be ages yielding a mean age of 9.9±0.7 ka that assigns the development of this lake level to the early part of the Lake Ojibway history. A smaller group (3 samples) is part of a more scattered distribution of older 10Be ages (with 2 outliers) that points to an inheritance of cosmogenic isotopes from a previous exposure, revealing an apparent mean age of 15.8±0.9 ka that is incompatible with the Ojibway inundation and the regional deglaciation. Our results provide the first direct 10Be chronology on the sequence of lake levels in the Ojibway basin, which includes the lake stage presumably associated with the confluence and subsequent drainage of Lakes Agassiz and Ojibway. This study demonstrates the potential of this approach to date glacial lake shorelines and underlies the importance of obtaining additional chronological constraints on the Agassiz-Ojibway shoreline sequence to confidently assign a particular lake stage and/or lake-level drawdown to a specific time interval of the deglaciation.

The Ziegler Reservoir fossil site near Snowmass Village, Colorado (USA), provides a unique opportunity to reconstruct high-altitude paleoenvironmental conditions in the Rocky Mountains during the Last Interglacial Period. We used four different techniques to establish a chronological framework for the site. Radiocarbon dating of lake organics, bone collagen, and shell carbonate, and in situ cosmogenic 10Be and 26Al ages on a boulder on the crest of a moraine that impounded the lake suggest that the ages of the sediments that hosted the fossils are between ~140 ka and >45 ka. Uranium-series ages of vertebrate remains generally fall within these bounds, but extremely low uranium concentrations and evidence of open-system behavior limit their utility. Optically stimulated luminescence (OSL) ages (n = 18) obtained from fine-grained quartz maintain stratigraphic order, were replicable, and provide reliable ages for the lake sediments. Analysis of the equivalent dose (DE) dispersion of the OSL samples showed that the sediments were fully bleached prior to deposition and low scatter suggests that eolian processes were likely the dominant transport mechanism for fine-grained sediments into the lake. The resulting ages show that the fossil-bearing sediments span the latest part of Marine Oxygen Isotope Stage (MIS) 6, all of MIS 5 and MIS 4, and the earliest part of MIS 3.

Weathering can be used as a highly effective relative age indicator. One such application involves etching of hornblende grains in soils. Etching increases with time (duration) and decreases with depth in soils and surficial sediments. Other variables, related to intensity of weathering and soil formation, are generally held as constant as possible so as to only minimally influence the time–etching relationship. Our study focuses on one of the variables usually held constant–climate–by examining hornblende etching and quartz/feldspar ratios in soils of similar age but varying degrees of development due to climatic factors. We examined the assumption that the degree of etching varies as a function of soil development, even in soils of similar age. The Spodosols we studied form a climate-mediated development sequence on a 13,000-yr-old outwash plain in Michigan. Their pedogenic development was compared to weathering-related data from the same soils. In general, soils data paralleled weathering data. Hornblende etching was most pronounced in the A and E horizons, and decreased rapidly with depth. Quartz/feldspar ratios showed similar but more variable trends. In the two most weakly developed soils, the Q/F ratio was nearly constant with depth, implying that this ratio may not be as effective a measure as are etching data for minimally weathered soils. Our data indicate that hornblende etching should not be used as a stand-alone relative age indicator, especially in young soils and in contexts where the degree of pedogenic variability on the geomorphic surface is large.

One of the major issues in (palaeo-) climatology is the response of Antarctic ice sheets to global climate changes. Antarctic ice volume has varied in the past but the extent and timing of these fluctuations are not well known. In this study, we address the question of amplitude and timing of past Antarctic ice level changes by surface exposure dating using in situ produced cosmogenic nuclides (10Be and 21Ne). The study area lies in the Ricker Hills, a nunatak at the boundary of the East Antarctic Ice Sheet in southern Victoria Land. By determining exposure ages of erratic boulders from glacial drifts we directly date East Antarctic Ice Sheet variations. Erosion-corrected neon and beryllium exposure ages indicate that a major ice advance reaching elevations of about 500 m above present ice levels occurred between 1.125 and 1.375 million years before present. Subsequent ice fluctuations were of lesser extent but timing is difficult as all erratic boulders from related deposits show complex exposure histories. Sample-specific erosion rates were on the order of 20–45 cm Ma-1 for a quartzite and 10–65 cm Ma-1 for a sandstone boulder and imply that the modern cold, arid climate has persisted since at least the early Pleistocene.

We present 21Ne exposure ages of erosional glaciogenic rock surfaces on nunataks in northern Victoria Land, Antarctica: i) in the Prince Albert Mountains and ii) near Mesa Range. These nunataks are located directly at the margin of the polar plateau and therefore provide an immediate record of ice volume changes of the East Antarctic Ice Sheet, not biased by ice shelf grounding or narrow valley sections downstream the outlet glaciers. The sampling locations overlook the present ice surface by less than 200 m, but were last covered by ice 3.5 Ma bp (minimum age, not corrected for erosion). This strongly indicates that the ice sheet has not been substantially thicker than today since at least the early Pliocene, which supports the hypothesis of a stable East Antarctic Ice Sheet. First absolute ages are reported for the alpine topography above the erosive trimline that typically marks the upper limit of glacial activity in northern Victoria Land. Unexpectedly low nuclide concentrations suggest that erosion rates on the alpine topography are considerably higher due to the steep slopes than those affecting flat erosional surfaces carrying Antarctic tors.

The question of how stable the climate in Antarctica has been during the last few million years compared to the rest of the planet is still controversial. This study attempts to add new information to the discussion by reconstructing the timing and spatial extent of glacial advances in northern Victoria Land over tens of thousands to millions of years. In Terra Nova Bay region, surface exposure ages and erosion rates of glacially rounded bedrock and glacial erratics have been determined using the cosmogenic nuclides 3He, 10Be and 21Ne. Three morphological units have been analysed. They yield minimum ages of 11 to 34 ka, 309 ka, and 2.6 Ma, respectively. Erosion rates were as low as 20 cm Ma−1 since middle Pliocene time. Taking erosion into account, the oldest surface is 5.3 Ma old. Pleistocene glacier advances had considerable extent, reaching up to 780 m above modern ice levels, but have been restricted to the valleys since at least mid-Pliocene. The existence of landscapes of mid-Pliocene age in northern Victoria Land implies that the climatic stability of the McMurdo Dry Valleys is not unique within the Transantarctic Mountains, but rather the expression of a constantly cold and hyperarid climate regime in entire Victoria Land.