Boreas最新文献

{"title":"Drivers of glacially induced fault reactivation in the Baltic Sea sector of the Tornquist Fan","authors":"Elisabeth Seidel,&nbsp;Holger Steffen,&nbsp;Rebekka Steffen,&nbsp;Niklas Ahlrichs,&nbsp;Christian Hübscher","doi":"10.1111/bor.12689","DOIUrl":"https://doi.org/10.1111/bor.12689","url":null,"abstract":"<p>We analyse the effect of Quaternary glaciations on the complex tectonic pattern within the southwestern Baltic Sea, a sector of the transition zone from the East European Craton to the West European Platform. This area comprises the Caledonian Trans–European Suture Zone in the south and the Tornquist Zone in the north. Multiple fault zones in between, with different strike and dip angles, and characters (normal, thrust/reverse, strike-slip), document like scars the alternately transpressional and transtensional stress activities since the Palaeozoic. We determine the strike directions and dip angles of more than 40 potential glacially reactivated faults identified in 2D marine reflection seismic data. Finite element simulations of different glacial isostatic adjustment models provide glacially induced Coulomb failure stress changes (ΔCFS) at the faults over time, starting 200 000 years ago (200 ka, Saalian phase) up to 1000 years into the future. Assuming strike-slip or thrust/reverse background stresses, a potential reactivation of each fault is analysed. The detected reactivation phases are related to the waxing and waning ice masses (Late Saalian ice advances: <i>c.</i> 170–135 ka ago; Weichselian ice advances: 70–60, 45–38, 26–14 ka ago) and point to an activation in front of the ice margin. Comparing the ΔCFS results of the individual faults laterally and over time, we found that the location of the fault, depending on its position during a glacial maximum, has an important effect on its reactivation potential. The closer a fault was located to the former ice margin, the higher was the glacially induced stress during the ice retreat. Based on earlier findings in Germany and Denmark, glacially triggered faults are a typical consequence of the Fennoscandian glaciation throughout northern central Europe, and this also applies to future glaciation phases.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 2","pages":"220-245"},"PeriodicalIF":2.4,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12689","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A synthesis of luminescence and 14C dated dust mass accumulation rates for loess-palaeosol sequences from the Middle Danube Basin","authors":"Zoran M. Perić,&nbsp;Milica G. Radaković,&nbsp;Rastko S. Marković,&nbsp;Slobodan B. Marković","doi":"10.1111/bor.12696","DOIUrl":"https://doi.org/10.1111/bor.12696","url":null,"abstract":"<p>The Middle Danube (Carpathian) Basin is considered to encompass some of the thickest and most complete records of aeolian dust deposition in Europe, covering the last two glacial–interglacial cycles. In this study, independent, published chronologies based on absolute dating methods were compiled for 34 loess-palaeosol sequences and modelled using Bayesian statistics. Mass accumulation rates (MARs) calculated from the Bayesian age models range from 50 to 1922 g m⁻² a⁻¹ with a mean value of 317±35 g m⁻² a⁻¹. The glacial–interglacial changes of the MAR estimates only partially agree with the accepted dust deposition model, where high accumulation rates are observed during the cold glacial stages, while low values are typical for the warmer interglacial periods. There is a rapid increase of MAR values during Marine Isotope Stage (MIS) 2, with the highest deposition in most cases observed ~25–18 ka. During MIS 3, the dust deposition was 1.8 times higher than during MIS 4. Regionally, the MARs appear to be highest in the northern part of the Middle Danube Basin, showing decreasing values towards the south. However, due to a variety of factors such as low dating resolution, age distribution, and biases in the dating method, it is debatable whether these results are representative estimates of atmospheric dust activity in the Middle Danube Basin during MIS 5–MIS 1.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 2","pages":"179-201"},"PeriodicalIF":2.4,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12696","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochronological investigations at the maximum extent of the Fennoscandian Ice Sheet during the Late Weichselian glaciation in northern Germany","authors":"Nikolas Krauß,&nbsp;Andreas Börner,&nbsp;Michael Kenzler","doi":"10.1111/bor.12695","DOIUrl":"https://doi.org/10.1111/bor.12695","url":null,"abstract":"<p>This paper investigates the time-transgressive evolution of the Fennoscandian Ice Sheet (FIS) during the Late Weichselian glaciation. Recent models of the Last Glacial Maximum (LGM) strongly challenge a synchronous development of the FIS in the SW Baltic Sea area. Especially in northern Germany, a time-transgressive LGM is controversial. We present a new set of optically stimulated luminescence (OSL) ages, from sediments deposited at locations previously ascribed to the LGM main stationary line, from which numerical age data have not been published so far. The aim of this study was to contribute to the research on the maximum Weichselian ice extent in northern Germany, and to close the gap between Denmark in the north and the area in Germany and Poland in the SE, for which numerical age data of the LGM extent of the FIS are available. Samples were taken from sandur deposits proximal to the former ice margin. In total nine OSL samples were taken and analysed on quasi-single-grain level, taking into account possible effects of insufficient bleaching of sample material. With an average age of ~23±1 ka, the samples indicate LGM sandur formation during Marine Isotope Stage (MIS) 2. Our dating provides new insights into Late Weichselian (MIS 2, 27–11.7 ka) ice-sheet dynamics and strongly challenge a synchronous development of the FIS in the SW Baltic Sea area. The integration of our results into regional models argues for a small-scale asynchronous extent of the last FIS in northern Germany.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 2","pages":"246-257"},"PeriodicalIF":2.4,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12695","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An inventory of subglacial overdeepenings in southern Germany and Austria","authors":"Lukas Gegg,&nbsp;Bernhard C. Salcher,&nbsp;Thomas Pollhammer,&nbsp;Denis Cohen,&nbsp;Urs H. Fischer,&nbsp;Angela Landgraf","doi":"10.1111/bor.12693","DOIUrl":"https://doi.org/10.1111/bor.12693","url":null,"abstract":"<p>Subglacial overdeepenings are of interest for a number of applied and academic reasons, for example as groundwater reservoirs or as sedimentary archives of environmental change. Thus, efforts have been made to compile and morphometrically analyse such features on a large scale. While this includes several prominent studies focusing on the western part of the European Alps and their foreland, their eastern part lacks information. We present an inventory of &gt;100 individual overdeepened basins in southern Germany and Austria compiled from heterogeneous sources. These basins are typically incised ~200 m (max. ~1000 m) below ground surface and ~20 km (max. ~100 km) long, and thus of similar dimensions as overdeepenings in the western (Swiss) Alps and foreland. We observe a positive correlation of overdeepening area and depth with catchment size and both peak and average elevations, although large and deep basins also occur in small catchments. Generally, large overdeepenings are restricted to inner-Alpine fault zones or the primarily weak foreland Molasse. Especially in inner-Alpine settings, longitudinal profiles are highly irregular. In the eastern Alpine foreland, individual basins are frequently arranged in a radial pattern, a morphology that is not typical of the western foreland, and is a result of less constrained ice flow. On the valley scale, the depth of overdeepened basins correlates with modelled ice-flow parameters, thickness and basal velocity at peak glacial conditions. Together with their occurrence in low-elevation reaches, this suggests a rapid formation over a few millennia at most. On a smaller, local scale, basin depth is highly irregular. Finally, the existence of several generations of (similarly) large foreland overdeepenings, sometimes superimposed, indicates that these basins do not grow progressively over consecutive glacial cycles but that a negative feedback, likely related to the freezing of supercooled basal water, limits their dimensions.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 4","pages":"527-541"},"PeriodicalIF":2.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12693","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145341563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of the structural framework of the North German Basin on Pleistocene tunnel-valley formation","authors":"Jörg Lang,&nbsp;Anke Bebiolka,&nbsp;Vera Noack,&nbsp;Julia Schützke,&nbsp;Sarah Weihmann,&nbsp;Sonja Breuer","doi":"10.1111/bor.12694","DOIUrl":"https://doi.org/10.1111/bor.12694","url":null,"abstract":"<p>Tunnel valleys are impressive subglacial erosional landforms and may attain depths of almost 600 m. Climatic and glaciological factors exert the primary control on tunnel-valley formation. Furthermore, regional geological features, e.g. faults and salt structures, have been suggested as controlling factors for tunnel-valley formation. To improve the understanding of the impact of these geological factors on tunnel-valley incision, we compare the distribution and orientations of buried Pleistocene tunnel valleys in the North German Basin with regional geological features, such as basin geometry and infill, faults and salt structures. Our analysis shows that deep tunnel valleys are restricted to areas with thick erodible Cenozoic deposits. The correlation between the trends of tunnel valleys, faults and salt structures varies between the analysed regions. The orientations of tunnel valleys commonly follow the trends of faults and salt structures in regions where the structural trend is NNW–SSE to east–west and ice-flow directions were approximately parallel to this trend. However, correlations are rarely observed if the regional structural trend is NW–SE to WNW–ESE and ice advances occurred thus normal or oblique to the regional fault trend. Potential future tunnel-valley incision is regarded as a major challenge for the long-term safety of radioactive waste repositories because incision may reach depths under consideration for repositories. The presence and orientations of faults and salt structures, however, do not provide consistent indicators for future tunnel-valley incision.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 4","pages":"542-566"},"PeriodicalIF":2.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12694","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145341562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-proxy reconstruction of Lateglacial and Holocene mountain vegetation dynamics in Uri, Central Switzerland","authors":"Ursula Huonder,&nbsp;Laura Dziomber,&nbsp;Erika Gobet,&nbsp;Carolina Senn,&nbsp;Petra Zahajská,&nbsp;Willy Tinner,&nbsp;Christoph Schwörer","doi":"10.1111/bor.12691","DOIUrl":"https://doi.org/10.1111/bor.12691","url":null,"abstract":"<p>In the context of climate change, a long-term perspective is essential to understand future trajectories of mountain vegetation. We analysed the sediment record of Golzerensee (1411 m a.s.l.), a mountain lake in the transitional zone between the montane and subalpine vegetation belt in Uri, Central Switzerland. We reconstructed past vegetation responses to anthropogenic impact, fire activity and climatic changes dating back to <i>c</i>. 14 550 cal. a BP using pollen, stomata, macrofossil and microcharcoal analyses. The tree line, composed of <i>Betula</i> and <i>Pinus sylvestris</i>, reached Golzerensee during the Allerød <i>c</i>. 13 200 years ago, but tundra vegetation re-expanded during the Younger Dryas cooling (12 800–11 700 cal. a BP). With the rapid temperature increase at the onset of the Holocene, a closed forest established within a few decades around the study site. Concurrently, temperate taxa (<i>Ulmus</i>, <i>Tilia</i>, <i>Acer</i>, <i>Corylus avellana</i>) increased in the lowlands, likely reaching the elevation of the lake. <i>Abies alba</i> established locally during the Holocene Thermal Maximum (HTM) at 9600 cal. a BP and dominated closed, montane forests, delaying the westward expansion of <i>Picea abies</i> that established only from <i>c</i>. 7700 cal. a BP onwards. The concomitant occurrence of cultural indicator taxa, as well as an increase in charcoal influx and fungal dung spore concentrations suggest that human impact has facilitated the expansion of <i>Picea abies</i> by negatively affecting important competitors such as <i>Abies alba</i> through fire and browsing disturbance. With rising temperatures due to current climate change, <i>Abies alba</i> and other temperate species may regain their former relevance, leading to diverse mixed forests that were abundant during the HTM <i>c</i>. 10 000–5000 cal. a BP. However, future forest composition and landscape diversity will also be influenced by browsing disturbance and land use management.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 2","pages":"202-219"},"PeriodicalIF":2.4,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12691","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ribbed moraines formed during deglaciation of the Icelandic Ice Sheet: implications for ice-stream dynamics","authors":"Nína Aradóttir,&nbsp;Ívar Örn Benediktsson,&nbsp;Erla Guðný Helgadóttir,&nbsp;Ólafur Ingólfsson,&nbsp;Skafti Brynjólfsson,&nbsp;Wesley R. Farnsworth","doi":"10.1111/bor.12690","DOIUrl":"https://doi.org/10.1111/bor.12690","url":null,"abstract":"<p>Investigations of the geomorphological fingerprints of palaeo-ice streams are essential for enhancing our understanding of ice-stream behaviour. Cross-cutting flowsets of palaeo-ice streams, during and following the Last Glacial Maximum, have been suggested in northeast Iceland based on the mapping of streamlined subglacial bedforms (SSBs). To increase our understanding of the dynamics of the Icelandic Ice Sheet (IIS) during deglaciation, we investigate transverse ridges, together with glacifluvial and ice-marginal landforms, within the largest flowset. The main emphasis is on the transverse ridges, which are primarily interpreted as ribbed moraines – the first to be described in Iceland. Morphological data are combined with sedimentological analyses of the ribbed moraines. Our results show that the ribbed moraines are composed of pre-existing material, often exhibiting a base of stratified glacifluvial sediments draped with subglacial till. Deformation and thrust structures within both units suggest compressional flow during the formation of the ridges. Our results suggest the ribbed moraines develop due to velocity gradients under the lateral shear margin of an ice stream based on their distribution and often oblique orientation in relation to SSBs. The ribbed moraines superimpose and thus post-date the SSBs, signifying the waning stage of ice streaming. We suggest that the ridges formed during ice-stream shutdown following the Younger Dryas and/or Preboreal re-advances. Eskers and ice-marginal landforms imply channelized water drainage during the final deglaciation interrupted by short-lived re-advances. This study has implications for the style of deglaciation associated with ice streaming in the northeastern part of the IIS. We characterize the role of ribbed moraines within the ice sheet and identify directions for future work.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 3","pages":"328-350"},"PeriodicalIF":2.4,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12690","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"De Geer moraine internal architecture based on sedimentological and geophysical investigations and implications for ice-marginal reconstructions","authors":"Gwyneth E. Rivers,&nbsp;Robert D. Storrar,&nbsp;Antti E. K. Ojala,&nbsp;Joni Mäkinen,&nbsp;Camilla Holmroos,&nbsp;Naomi Holmes","doi":"10.1111/bor.12692","DOIUrl":"https://doi.org/10.1111/bor.12692","url":null,"abstract":"<p>De Geer moraines (DGMs) may act as valuable ice margin indicators; however, to date, their variable mode of formation has presented challenges for this utility. Morphometric investigations provide useful insights into formation processes, which can be developed using sedimentological and geophysical methods. Here we present sedimentological and ground penetrating radar (GPR) data of DGMs located in southwest Finland. Individual lithofacies were identified and interpreted using sediment architectural elements. These were correlated with neighbouring GPR radargrams and extrapolated across the wider study area. Generally, internal architecture presents a multi-phase structure with lower units representing subglacial traction till and ice margin infill deposits, truncated by a larger prominent push unit, which is then successively deformed via the overriding of active ice. Significantly, there are notable differences between proximal and distal structures, with proximal sides characterized by silts, clays, and diamicton with laminae, stratification and thrust planes, and distal sides characterized by poorly consolidated diamicton and proglacial water current reworkings. Internal architecture of both prominent and intermediate ridges is very similar, reflecting similar formation processes, however, slight differences also reflect inter-seasonal variations. Based on our findings, we present an integrated conceptual model for the genesis of DGMs whereby inter-seasonal ridge forming processes occur within a sub-aqueous ice-marginal environment. Our model highlights that DGMs can be subcategorized as: (i) sediment deposition at an unstable margin during summer calving, and/or (ii) sediment pushing at a stabilized margin during a winter re-advance. We do not find evidence of crevasse filling as a mechanism for DGM formation. We propose a landform assemblage classification whereby ‘De Geer terrain’ is used to describe series of parallel ridges arranged in a typical washboard-like configuration. This classification identifies all DGMs derived within a sub-aqueous ice-marginal environment, whilst also capturing the equifinal characteristics between individual landforms.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 4","pages":"687-710"},"PeriodicalIF":2.9,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12692","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145341619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increased aeolian activity linked to Neoglacial cooling and glacier advance in southern Greenland","authors":"Nicolaj K. Larsen,&nbsp;Marie-Louise Siggaard-Andersen,&nbsp;Jan-Pieter Buylaert,&nbsp;Andrew S. Murray,&nbsp;Jesper Olsen,&nbsp;Anthony Ruter,&nbsp;Kristian K. Kjeldsen,&nbsp;Anders A. Bjørk,&nbsp;Naja Mikkelsen,&nbsp;Kurt H. Kjær","doi":"10.1111/bor.12688","DOIUrl":"https://doi.org/10.1111/bor.12688","url":null,"abstract":"<p>Wind activity is a powerful force that shapes the landscapes of deserts, coastal areas, and regions adjacent to ice sheets, and it has significant implications for human settlement. In southern Greenland, it has been proposed that the increased wind and soil erosion observed around Norse settlements (~985–1450 CE) were caused by overgrazing by animals, which ultimately contributed to the decline of the Norse culture. Alternatively, some studies have linked the observed intensification of aeolian activity to changes in large-scale atmospheric circulation patterns in the North Atlantic. However, the timing and impact of this increased aeolian activity in southern Greenland remain uncertain due to a lack of well-dated records. In this study, we use a lake record and optically stimulated luminescence (OSL) dating of adjacent dunes to reconstruct the Holocene history of aeolian activity at Igaliku Kujalleq (Søndre Igaliku) in southern Greenland. Our findings indicate two periods of intensified aeolian activity over the past 10 000 years: from ~500 to 1200 CE and ~1450 CE. Importantly, the peak aeolian activity observed in the Igaliku Kujalleq records was unrelated to Norse activities and their decline. Instead, we suggest that changes in the North Atlantic atmospheric circulation pattern combined with Neoglacial glacier advances led to increased katabatic wind activity and triggered increased aeolian activity from large outwash plains.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 3","pages":"382-394"},"PeriodicalIF":2.4,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12688","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responses of shallow subarctic ponds to a warming climate in the Anthropocene: a palaeolimnological perspective from the Hudson Bay Lowlands, Canada","authors":"Connor Nishikawa,&nbsp;Andrew S. Medeiros,&nbsp;Jennifer Eamer,&nbsp;Brent B. Wolfe","doi":"10.1111/bor.12685","DOIUrl":"https://doi.org/10.1111/bor.12685","url":null,"abstract":"<p>Arctic ecotones contain dynamic freshwater ecosystems where aquatic biota vary across these transitions and as such can be especially susceptible to environmental change. Here, we examine the palaeoecology of two ponds in the ecotonal Hudson Bay Lowlands, subarctic Canada, to understand how aquatic biota have responded in an increasingly climate-stressed Anthropocene, and to better anticipate future changes. Using a multi-proxy palaeolimnological approach, we reconstruct past environmental conditions through the examination of subfossil chironomids (Diptera: Chironomidae) and compare these records to organic carbon and nitrogen elemental and isotope composition, and previously published cellulose-inferred lake water oxygen isotope records. Despite their close proximity, we found different chironomid assemblages in each pond that reflected differences in hydrological trajectories since 1940; an isolated pond exposed to evaporative stress showed an increasingly littoral chironomid assemblage, while a nearby basin that began receiving waters from a channel fen lost semi-terrestrial taxa associated with flooded grassy margins that became more permanently submerged. Even though large catchment-mediated changes resulted in a shift in some chironomids of both ponds, chironomid-based palaeo-temperature reconstructions demonstrated similar warming trends. Shifts in the ecology of subarctic lakes and ponds are expected to increase as the effects of climate change become more severe.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 3","pages":"370-381"},"PeriodicalIF":2.4,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12685","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144647809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}