Connecting changes in erosion and vegetation is necessary for predicting topographic and ecologic change in thawing permafrost landscapes. Formerly periglacial landscapes serve as potential analogs for understanding modern permafrost landscape change, yet compared to paleoenvironmental records at these sites, less is known about concurrent geomorphic processes, particularly their rates and relationships to climate change. Here, we target sediments preserved in a central Appalachian peat bog to reconstruct sedimentation across the last deglacial warming. We use ground-penetrating radar and geochemistry of cored bog sediments to quantify sedimentation timing, style, and provenance. Using 14C dating of sedimentary and geochemical shifts, we connect depositional changes to global climate and local vegetation change. We show that deglacial warming promoted deep soil disturbances via solifluction at ca. 14 ka. In contrast, relatively wetter conditions from ca. 10–9 ka promoted shallow disturbance of hillslopes via slopewash, which corresponds to a time of vegetation change. Our results highlight climate-modulated erosion depth and processes in periglacial and post-periglacial landscapes. The existence of similar erosion and vegetation records preserved regionally implies these dynamics were pervasive across unglaciated Appalachian highlands, aiding in reconstructing erosion responses to warming at a resolution with implications for predicting high-latitude landscape responses to disturbance.

During Lateglacial cold periods, permafrost developed throughout Scotland, sediment-mantled slopes were extensively modified by solifluction and other forms of periglacial mass movement, large-scale sorted patterned ground formed on plateaux, and enhanced rockfall resulted in talus accumulation below cliffs. Most rock-slope failures occurred within five millennia following ice-sheet deglaciation, with many probably triggered by uplift-induced earthquakes; numerous debris-free scarps represent sites where Lateglacial rockslide debris was excavated by glaciers during the Younger Dryas Stade (∼12.9–11.7 ka). Sandar and outwash fans deposited by glacial rivers during ice-sheet retreat were incised to form high-level terraces. Under the cool temperate but relatively stable climate of the Holocene, solifluction and patterned ground formation continued to operate on high ground, though accumulation of high-level aeolian deposits on most mountains was terminated by erosion during the Little Ice Age. Drift-mantled slopes and talus slopes have been extensively eroded by translational failures and debris flows, the latter depositing debris cones on upland valley floors. The incidence of Holocene rockslides has been much lower than during the Lateglacial period. Dating of alluvial deposits and low Holocene terraces suggests no consistent pattern of Holocene floodplain evolution: incision has apparently dominated in the Highlands, aggradation in the lowlands, and floodplains in the Southern Uplands have asynchronous histories of incision and aggradation. Studies of floodplain behaviour over the past 200–300 years suggest that though major floods rework the floodplains of braided and piedmont rivers, there is no tendency towards net floodplain aggradation or incision. Most valley-side alluvial fans accumulated episodically in the last 4000 years, many in response to lowering of hillslope stability by woodland clearance. For many postglacial landsystems, disentangling the effects of declining paraglacial sediment supply, climate change and local influences (extreme rainstorm events or anthropogenic impacts) remains challenging.

Identification of bouldery landforms in mountains and correctly understanding their formative processes play an important role in reconstructing the geomorphic history of a region. We propose that blocks were liberated by frost cracking and wedging of cliff walls during the last glacial period. However, we further suggest and test four hypotheses comprising different scenarios for preconditioning by chemical weathering and subsequent block transport using terrain analysis, characterization of boulders, and 10Be exposure dating. Frost shattering from the backing cliff produced the boulders since the beginning of the last glacial period (~80 ka), and gelifluction transported them downslope throughout the last glacial period. Their activity then entered a dormant phase at the beginning of the Holocene. Distribution patterns of exposure ages of tors and block streams are similar to those of previous studies, implying that bouldery landscapes in the southern Korean Peninsula were likely to be formed by similar processes under periglacial conditions. The timing of active periods in transport of block streams corresponds well with the cold periods identified in regional and global climate proxy records. Interestingly, the activity of block streams in the study area reached a maximum during Marine Oxygen Isotope Stage 3 to 2 when the growth rate of nearby speleothems was lowest.

The major climatic variations that have affected the summit slopes of the higher Apennine massifs in the last 6000 yr are shown in alternating layers of organic matter-rich soils and alluvial, glacial and periglacial sediments. The burial of the soils, triggered by environmental–climatic variations, took place in several phases. For the last 3000 yr chronological correlations can be drawn between phases of glacial advance, scree and alluvial sedimentation and development of periglacial features. During some periods, the slopes were covered by vegetation up to 2700 m and beyond, while in other phases the same slopes were subject to glacial advances and periglacial processes, and alluvial sediments were deposited on the high plateaus. Around 5740–5590, 1560–1370 and 1300–970 cal yr B.P., organic matter-rich soils formed on slopes currently subject to periglacial and glacial processes; the mean annual temperature must therefore have been higher than at present. Furthermore, on the basis of the variations in the elevation of the lower limit reached by gelifraction, it can be concluded that the oscillations in the minimum winter temperatures could have ranged between 3.0°C lower (ca. 790–150 cal yr B.P.) and 1.2°C higher (ca. 5740–5590 cal yr B.P.) than present minimum winter temperatures. During the last 3000 yr the cold phases recorded by the Calderone Glacier advance in the Apennines essentially match basically the phases of glacial advance in the Alps.

A lake sediment core from the Uinta Mountains of northern Utah was analyzed to constrain the timing of late Holocene periglacial activity. Records of numerous physical properties were converted to time series spanning the past 5300 years using a depth-age model based on four AMS 14C dates. Long-term decreases in organic content and increases in bulk density attest to increasing inputs of clastic sediment. Abundance of mineral P, signaling physical bedrock weathering, reaches maximum values ca. 2900, 2150, and 1400 cal yr BP, coincident with finer median grain size and a shift toward darker red sediment. These peaks, interpreted as signals of periglacial activity, align with pulses of rock glacier activity in Colorado determined from lichenometry. The youngest peak coincides with lichenometric ages previously determined for periglacial deposits upstream from the lake. A pulse of renewed periglacial activity ca. 400 cal yr BP represents the Little Ice Age. The late 20th century witnessed extremely high values of organic matter and biogenic silica, and unprecedented low values of C:N, reflecting greatly enhanced in-lake productivity, likely due to disturbance in the watershed.

The formation of segregated ice is of fundamental importance to a broad range of permafrost and periglacial features and phenomena. Models have been developed to account for the microscopic interactions that drive water migration, and predict key macroscopic characteristics of ice lenses, such as their spacings and thicknesses. For a given set of sediment properties, the temperature difference between the growing and incipient lenses is shown here to depend primarily on the ratio between the effective stress and the temperature deviation from bulk melting at the farthest extent of pore ice. This suggests that observed spacing between ice lenses in frozen soils, or traces of lenses in soils that once contained segregated ice, might be used to constrain the combinations of effective stress and temperature gradient that were present near the time and location at which the lower lens in each pair was initiated. The thickness of each lens has the potential to contain even more information since it depends additionally on the rate of temperature change and the permeability of the sediment at the onset of freezing. However, these complicating factors make it more difficult to interpret thickness data in terms of current or former soil conditions.

One of the distinguished efforts of A.L. Washburn was to reconstruct mean annual air temperature using periglacial features as climate indicators. This paper reviews existing periglacial indicators and proposes a strategy to improve their thermal resolution based on recent periglacial process studies, with a focus on solifluction and thermal contraction cracking and associated landforms/structures. Landforms resulting from solifluction reflect both the depth subjected to freeze–thaw and the thickness of frost-susceptible soils. The thickness of a solifluction structure can be used to infer the dominant freeze–thaw regime and minimum seasonal frost depth. Ice-wedge pseudomorphs have limited potential as a climate indicator because (1) they mainly reflect extreme winter temperatures, (2) their thermal thresholds depend on the host material, and (3) they need to be distinguished from frost wedges of other origin produced under different thermal and/or material conditions. Monitoring studies of currently active ice wedges suggest that ice-wedge cracking requires a combination of low temperature and large temperature gradients in the frozen active layer. Further field monitoring of periglacial processes and their controlling factors under various climate conditions and in various materials are needed, however, to improve the resolution of periglacial paleoclimate indicators.

Periglacial conditions beyond the Wisconsin glacial limit produced wind-transverse corrugations in east-central Pennsylvania. The corrugations are low, linear ridges typically several hundred meters long, 10–30 m wide, and 3–8 m above the local slope. They are composed of matrix-supported diamictons. Depending upon landscape position, the corrugations form welts, step and risers, or ground-ice-scar ramparts. The average direction normal to the corrugations is clustered at 118°/298°, similar to the late Wisconsin or early Holocene wind direction of 284° measured from a nearby fossil dune field. But the corrugations were neither eroded nor deposited by wind. Rather, they record nivation beside snow that accumulated in wind-transverse patterns. Their wide distribution implies that the region was treeless during the late Wisconsin maximum. Present discontinuities in these and other periglacial features suggest wasting of ice-rich fill in upland valleys, with consequent widening of stream channels and fan growth, at the end of periglacial time.

Recent accounts suggest that periglacial processes are unimportant for large-scale landscape evolution and that true large-scale periglacial landscapes are rare or non-existent. The lack of a large-scale topographical fingerprint due to periglacial processes may be considered of little relevance, as linear process–landscape development relationships rarely can be substantiated. Instead, periglacial landscapes may be classified in terms of specific landform associations. We propose “cryo-conditioning”, defined as the interaction of cryotic surface and subsurface thermal regimes and geomorphic processes, as an overarching concept linking landform and landscape evolution in cold regions. By focusing on the controls on processes, this concept circumvents scaling problems in interpreting long-term landscape evolution derived from short-term processes. It also contributes to an unambiguous conceptualization of periglacial geomorphology. We propose that the development of several key elements in the Norwegian geomorphic landscape can be explained in terms of cryo-conditioning.

At two localities adjacent to Hatherton Glacier, Darwin Mountains, a thick glacio-lacustrine sequence underlies the main diamictite facies of the Darwin Tillite (Metschel Tillite), and at one of these locations a glacio-lacustrine sequence also conformably overlies the diamictite. These deposits record the initial advance and final retreat of the Gondwana ice cap. Other, pro- and periglacial phases within these sequences record several minor advances and retreats of the ice sheet. Carbonaceous sediments above and below the main diamictite phase show that vegetation was established near the ice margin, suggesting that present-day ice margin temperatures are colder than those experienced during the Permo-Carboniferous (Gondwana) glaciation. It appears that there was little or no erosion of the Devonian Taylor Group which underlies the glacial sequence. The apparent erosional nature of the contact between the Permo-Carboniferous glacial sequence and the overlying Permian coal measures is attributed to surface winnowing of unconsolidated tills and locally the units are conformable.

Deposits of windblown sand up to 4 m thick on the Torridon Sandstone massif of An Teallach are shown to be of predominantly niveo-aeolian origin, a form of sedimentation hitherto unrecognised in upland Britain. Sand grains weathered from bedrock and from exposed clasts on plateau areas are blown on to the winter snowpack on surrounding slopes. When the snow melts, the grains are lowered on to the underlying vegetation, which traps the sand and thus allows a stable deposit to accumulate. The deposits formed in this way are massive, poorly sorted and coarser than most aeolian deposits, comprising mainly medium sand (212–600μm) with a substantial proportion of coarse sand and even very small pebbles. The coarseness and poor sorting of the sands reflect the size of grains available for transportation, the strength of the wind, short transport distances and admixture of different grades of sand during deposition. Sand accumulation began in the Early Flandrian before c. 7900 BP, but was eventually much reduced by the establishment of vegetation cover over the plateau source area. Recent disruption of this vegetation cover triggered either by increased storminess or overgrazing resulted in extensive erosion of sand deposits on the plateau and their redeposition on surrounding slopes. Niveo-aeolian deposition continues on lee slopes at present, but is offset by erosion of unvegetated scarps at the margins of the deposits.