Journal of Quaternary Science最新文献

The sediment signature of glacial erosion products exported from Hudson Strait to the Labrador Sea during Hudson Strait Heinrich (HS-H) events is evaluated using four distinct proxies: paired δ¹⁸Ο and δ¹³C data on the carbonate fraction, εNd and U–Pb isotopes in the silicate fraction, the mineral composition of the <2 mm bulk sediment fraction, and the lithologic composition of the >2 mm granules. Most detrital carbonate was eroded from Ordovician limestones on the floor of Hudson Strait. Silicate components were derived largely from Paleoproterozoic metamorphic and igneous bedrock, mostly on southern Baffin Island. A five-component sediment unmixing model shows that HS-H sediments were predominantly from Hudson Strait, whereas intervening sediment in the SW Labrador Sea has a predominant signature from Labrador but includes some detrital carbonate. Carbonate derived from the Western Basin and red sandstone granules from Keewatin are most abundant in the early part of HS-H 1, 2, and 4. Sediment budgets imply 10–15 m deepening of Hudson Strait over the last glacial cycle. The magnitude and longevity of detrital carbonate transport by icebergs during HS-H events require the inmixing of debris throughout the entire ice stream as it crossed the Abloviak sill.

Submarine landslides can generate tsunamis and pose risks to underwater infrastructure, but a lack of direct observations of such slides hinders our understanding of their development and hazard potential. Studying the morphology of past slides can offer insights into their preconditioning and failure. Here, new high-quality 2D and 3D seismic data were used to determine, for the first time, the extent and morphology of the Stad Slide (~0.4 Ma) on the northeast Atlantic margin. With a volume of ~4300 km³ and a maximum thickness of ~360 m, we reveal that this slide is the largest by volume on the proximal North Sea Fan and amongst the largest known megaslides globally. Its large volume was likely facilitated by retrogressive development along layers of glacimarine and contouritic sediment. The broad timing of the Stad Slide aligns with enhanced glacial sedimentation in this region, which is likely to have preconditioned failure by increasing overpressure in underlying sediments. The slide headwalls are infilled by an ~200 m-thick contourite drift that may have formed the weak layer for subsequent sliding on the North Sea Fan.

How fast is Planet Earth being eroded? How much of this erosion is “natural”, and how much has it accelerated due to human action? More than a century ago, Sherlock (1922) claimed that the amount of sediment moved by humankind exceeded that of any other geomorphic agent. But was he right? The question has been much debated in the years since then (Hooke, 2000; Syvitski et al., 2005; Wilkinson, 2005; Giosan et al., 2017). Alongside numerical modelling, two principal empirical approaches have been adopted in attempts to answer this question. The first involves the measurement of contemporary rates of sediment flux (i.e., sediment transport) via different agencies. Flux of sediment reflects landscape stability and instability, whether of climatic, tectonic or human origin, or some combination. Transporting agencies include glacier ice and the wind (mainly aeolian dust), but globally, the dominant means of sediment movement from land to sea is via rivers, as suspended or dissolved load (Gibbs, 1970; Douglas, 1990; Milliman,1990). Studies have ranged in spatial scale from measurement of experimental soil erosion plots under different land cover types (e.g., Rapp, 1975), through small catchment monitoring (Boardman et al., 1990), to analysis of sediment discharge from major river basins like the Yangtse and Ganges (Walling and Webb, 1983; Summerfield and Hulton, 1994). The alternative approach is historical, commonly involving the examination of sedimentary “archives” in lakes, river valleys and estuaries to establish longer-term rates of change. The papers in this joint virtual special issue (VSI) of Geoarchaeology and Journal of Quaternary Science adopt this second strategy via a series of empirical-historical case studies that cover a range of different environments and timescales (Table 1). It is an approach based on the assumption that at some point in the past, human impact on erosion rates was minimal relative to natural agencies, and that this provides a baseline for assessing any subsequent increase of anthropogenic causation. In regions such as Europe and South Asia, this baseline is believed to date to mid-Holocene times, whereas it continued into the late Holocene in areas such as temperate North America (van Vliet-Lanoë et al., 1992; Dearing and Jones, 2003; Hoffmann et al., 2010).

While a shared theme underpins this joint special issue, that of soil erosion, and the study of the complex interplay between climate and anthropogenic mechanisms, the allocation or “badging” of articles as either Geoarchaeology or Journal of Quaternary Science was based on the extent to which colleagues explicitly engaged with archaeological phenomena in their studies. For example, van Zon et al.'s (2025) assessment of the role of Roman road

The Holocene history of Australia's climate is surprisingly poorly understood. This is, in part, because of the relatively weak forcing of Holocene climate versus that of the late Pleistocene. However, it is commonly suggested that eastern Australia dried during the mid- to late-Holocene and that this was in response to increased activity in the El Niño–Southern Oscillation (ENSO), in particular, the intensification of the El Niño phase of ENSO. While this has been inferred from numerous locations, data from K'gari (a subtropical sand island adjacent to the east coast) was amongst the first used to develop this hypothesis and features heavily in the discussion of ENSO intensification. This study examines published and new data from three ≥4.5 m deep K'gari lakes that demonstrate a strong drying event during the middle Holocene (from 7640 to 5600 cal a BP), followed by a wetter late Holocene climate. This contrasts somewhat with previous arguments about K'gari's history that suggest a late Holocene drying. In turn, this indicates a need to re-evaluate the notion that ENSO intensification drove late-Holocene drying in the region. It also indicates that even large, deep lakes on K'gari, which are iconic landmarks with substantial cultural, ecological and economic values, are vulnerable to drying.

Understanding postglacial ontogeny in Arctic lakes helps contextualize modern-day climatic change. We used sediment cores to characterize ecological succession in three south-central Baffin Island lakes from deglaciation (c. 7–8k cal a BP) to present. Trends in diatom (Bacillariophyceae) and chironomid (Diptera: Chironomidae) assemblages were compared between two small lakes (depth ≤ 12 m, area ≤ 0.04 km²) and the north-western lagoonal system of Nettilling Lake, the largest freshwater lake in the Canadian Arctic Archipelago (sampling depth = 3 m, total area = 5543 km²). Ecological trajectories differed between the small lakes despite morphological similarities. The northern, lower elevation, small lake showed expected acidification and oligotrophication, while the southern, higher elevation lake experienced hydrologic disturbance likely associated with permafrost degradation. The Nettilling Lake core did not show clear ontogenetic processes, but the high sedimentation rate from approx 6.7 to 5.9k cal a BP (likely from glacial melt) obscured in-depth analysis of subsequent changes. While the composition of chironomid assemblages varied between lakes, all three lakes showed a minor shift from Tanytarsini to Orthocladiinae taxa over their development, which could reflect ontogenetic changes to resource availability. The different trajectory experienced by each study lake highlights the relevance of catchment properties in structuring lake development.

Future projections of climate change in the subtropics suggest warming and drying, while evidence from warm periods in the past shows increases in subtropical temperatures and precipitation. Eastern Australia is subject to interannual hydroclimate drivers and has experienced extreme flooding and droughts in recent years. To understand how the changes to the mean global conditions may affect sensitive environments, such as the wetlands in this region, baseline records of mean temperatures, especially since and during the Last Glacial Maximum (LGM), are vital. Several palaeoenvironment records exist from the coastal sand islands of Minjerribah (North Stradbroke Island) and K'gari (Fraser Island), south-east Queensland. However, these records appear to show divergent responses to climate change. Whilst there are a variety of proxies used for environmental reconstruction (e.g., pollen, charcoal, dust flux), there are relatively few continuous records of quantitative temperature, which limits our understanding of the causes of environmental change. Presented here is a palaeoclimate reconstruction spanning the LGM to Holocene, utilising glycerol dialkyl glycerol tetraethers (GDGT), for Broutha Waterhole, a subtropical perched wetland in the Cooloola Sand Mass, Queensland, Australia, located between Minjerribah and K'gari. The GDGT-based palaeotemperature reconstruction features a temperature minimum of 17.0°C (~4.3°C maximum cooling) during the LGM, which is very close to the palaeotemperature recorded from K'gari and consistent with the Australia-wide temperature range. A progressively warming temperature during the deglacial is interrupted by a temperature decline (0.8°C–1.6°C) coincident with the Antarctic Cold Reversal (ACR), followed by a stable warm Holocene. It should be noted that there are possibilities of hiatuses of different periods at Cooloola Sand Mass compared to K'gari and Minjerribah, which may imply different control on the sediment deposition. This study provides a palaeotemperature record through the LGM and deglacial period that contributes to the limited quantitative temperature data in the subtropics.

We report 43 new ¹⁰Be exposure ages and six ²⁶Al/¹⁰Be measurements from replicates from a small piedmont mountain glacier located at Cape Farewell (south Greenland) and temperature anomalies estimated from equilibrium-line altitude (ELA) changes derived from 3D glacier reconstruction carried out using the ‘GlaRe’ toolbox. Both ELA-derived temperature estimations and climate conditions documented from the transient simulation TraCE-21ka help us to explore the causes of glacier changes during the investigated period. Exposure ages span from the Oldest Dryas to the Late Holocene, revealing that the GrIS retreat in this valley permitted the individualisation or formation of a mountain glacier early in the Lateglacial. Interestingly, four of the six ²⁶Al/¹⁰Be ratios come from samples located on the oldest moraines do not reveal inheritance. The two other ratios suggest inheritance up to 6 ka. The oldest moraine combining a frontal and a lateral remain is dated to 18.4 ± 0.8 ka. Between 18 ka and ~14.7 ka, the glacier experienced a significant retreat interrupted by at least three minor advances or stillstands. We did not find any moraine formed either during the Younger Dryas, or during the Early and the Mid Holocene. The largest Holocene glacier advance occurred ~4.4 ka. Two other younger moraines were formed at ~2.9 ka and probably during the LIA. Temperatures of 3.3°C and 1.7°C colder than today may explain the glacier extent during the Lateglacial and the Holocene, respectively. Complementary dry regional climate conditions estimated from TraCE-21ka simulations during the Early Holocene may explain why the glacier was smaller than during the Late Holocene.