Boreas最新文献

{"title":"Holocene relative shore-level changes and development of the Ģipka lagoon in the western Gulf of Riga","authors":"Alar Rosentau,&nbsp;Ieva Grudzinska,&nbsp;Edyta Kalińska,&nbsp;Helena Alexanderson,&nbsp;Valdis Bērziņš,&nbsp;Aija Ceriņa,&nbsp;Laimdota Kalniņa,&nbsp;Jānis Karušs,&nbsp;Kristaps Lamsters,&nbsp;Merle Muru,&nbsp;Māris Nartišs,&nbsp;Līga Paparde,&nbsp;Tiit Hang","doi":"10.1111/bor.12628","DOIUrl":"10.1111/bor.12628","url":null,"abstract":"<p>Holocene relative shore-level changes and development of the Ģipka palaeolagoon in the western Gulf of Riga are reconstructed using multiproxy analyses by combining litho-, biostratigraphical and chronological data with remote sensing and geophysical data. The results show the development of the Ģipka basin from the Ancylus Lake/Initial Litorina Sea coastal zone (before <i>c.</i> 9.1 cal. ka BP) to coastal fen (<i>c.</i> 9.1 to 8.4 cal. ka BP) and gradual development of the Litorina Sea lagoon (<i>c.</i> 8.4 to 4.8 cal. ka BP) and its transition to a freshwater coastal lake (<i>c.</i> 4.8 to 4.6 cal. ka BP), fen (<i>c.</i> 4.6 to 4.2 cal. ka BP), and river floodplain (since <i>c.</i> 4.2 cal. ka BP). The highest shorelines of the Ancylus Lake and Litorina Sea were mapped at an elevation of 12–11 and 9 m a.s.l., respectively. A new relative shore level (RSL) curve for the western Gulf of Riga was constructed based on RSL data from the Ģipka area and from nearby Ruhnu Island studied earlier. The reconstruction shows that the beginning of the last marine transgression in the western Gulf of Riga started at <i>c.</i> 8.4 cal. ka BP, and concurred with the 1.9 m RSL rise event recorded from the North Sea basin. Diatom analysis results indicate the existence of the Ģipka lagoon between <i>c.</i> 7.7 and 4.8 cal. ka BP, with the highest salinity <i>c.</i> 6.1 cal. ka BP. During the existence of the brackish lagoon, settlement sites of the Neolithic hunter–gatherer groups existed on the shores of the lagoon in the period <i>c.</i> 6.0 to 5.0 cal. ka BP.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 4","pages":"517-537"},"PeriodicalIF":2.2,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12628","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47165649","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":"Variations in Holocene fire activity and its controls in the Ningshao Plain, eastern China","authors":"Konglan Shao,&nbsp;Jianping Zhang,&nbsp;Hongbo Zheng,&nbsp;Zhaoyan Gu,&nbsp;Bing Xu,&nbsp;Qing Yang,&nbsp;Keyang He,&nbsp;Huayu Lu","doi":"10.1111/bor.12627","DOIUrl":"10.1111/bor.12627","url":null,"abstract":"<p>Extensive fires pose catastrophic threats to both human and natural ecosystems. Understanding the history of fire, particularly Holocene palaeofire activity in densely populated areas, is essential for predicting future fire risks and developing effective fire management policies. The complexity of fire activity is influenced by various factors, including climate and anthropogenic activities. In this study, we analysed microcharcoal from the top 35.36 m of a well-dated sediment core HMD1401 in Ningshao Plain, eastern China. We combined our findings with phytolith and diatom evidence to obtain a comprehensive understanding of variations in Holocene fire activity and its controls. The results showed that there was higher fire activity during the early and late Holocene and less fire activity during the mid-Holocene. More frequent fire occurred from <i>c.</i> 10 000–7000 cal. a BP and was primarily caused by abundant biomass and high seasonal flammability due to increased annual temperature and precipitation and warm but dry winter climate. Fire occurrences between <i>c.</i> 7000–2000 cal. a BP remained at a low level, except for the periods <i>c.</i> 5900–5600 cal. a BP and <i>c.</i> 5300 cal. a BP, which may have been caused by extreme climate events. The impact of fire caused by human activity was significantly enhanced during the last two millennia.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 4","pages":"507-516"},"PeriodicalIF":2.2,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12627","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48646873","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 deglaciation of Upernavik trough, West Greenland, and its Holocene sediment infill: processes and provenance","authors":"Jens Weiser,&nbsp;Jürgen Titschack,&nbsp;Dierk Hebbeln","doi":"10.1111/bor.12626","DOIUrl":"10.1111/bor.12626","url":null,"abstract":"<p>Under glacial climates, continental ice sheets such as, e.g., the Greenland Ice Sheet, extended onto the continental shelves and often carved out deep cross-shelf troughs. The sedimentary infill of such troughs commonly is a product of the complex interactions between the ice sheets, largely driving sediment input into the ocean, and the surrounding water masses. Off West Greenland, research has focused on the Disko and Uummannaq troughs, leaving the northerly adjacent Upernavik trough relatively understudied. Hence, neither the chronology of deglaciation nor the details of its postglacial infill are sufficiently well understood. Here, we combine computed tomography image-derived information with geochemical and granulometric data from four sediment cores recovered from the Upernavik trough that point to (i) deglaciation of the mid-shelf probably around 13.4 cal. ka BP that was most likely driven by a northward advection of warmer Atlantic waters during the Bølling–Allerød, (ii) the presence of widespread mass wasting around 8 cal. ka BP on the inner shelf and (iii) the complex interplay between various modes of sediment input, transport and deposition under hemipelagic sedimentation afterwards. While this interplay complicates provenance studies, we identify two major sediment delivery mechanisms that control transport and deposition from four sediment source areas. Through the Early Holocene the relative contributions of sediments from the various sources changed from a predominantly local origin to more southerly sources, mainly driven by decreasing input from the local sources. The integration of relative sediment source contributions with varying sedimentation rates challenges previous studies postulating intensified sediment delivery from the south through a greater influence of the West Greenland Current and highlights the need for the integration of sediment input and transport mechanisms into provenance studies in the area.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 3","pages":"314-340"},"PeriodicalIF":2.2,"publicationDate":"2023-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12626","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49466174","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":"Spatial interpretation of high-resolution environmental proxy data of the Middle Pleistocene Palaeolithic faunal kill site Schöningen 13 II-4, Germany","authors":"Brigitte Urban,&nbsp;Kim J. Krahn,&nbsp;Thomas Kasper,&nbsp;Alejandro García-Moreno,&nbsp;Jarod M. Hutson,&nbsp;Aritza Villaluenga,&nbsp;Elaine Turner,&nbsp;Sabine Gaudzinski-Windheuser,&nbsp;Dalia Farghaly,&nbsp;Mario Tucci,&nbsp;Antje Schwalb","doi":"10.1111/bor.12619","DOIUrl":"10.1111/bor.12619","url":null,"abstract":"<p>To spatially characterize the palaeolakeshore environment at the archaeological kill site Schöningen 13 II-4 of the Middle Pleistocene Reinsdorf sequence, in-depth palynological, geochemical, aquatic microfossil and archaeological analyses were undertaken on sediment sections with an average thickness of about 15 cm, concordantly overlain by faunal remains, dominated by horse, from the unique ‘Spear Horizon’ layers of the 1995 excavation campaign. The data reveal a distinctive lake level drop, documented by the change from a carbonate-rich lake marl to a carbonate-free organic mud with increased carbon content and decreasing C/N, Si/Al, Si/K and Fe/Al ratios, indicating a higher pedogenic supply of organic matter and drier conditions at the site. Compared with older, similar transitional phases of lake level changes occurring within the Reinsdorf sequence, it is important that these youngest sediments are undisturbed, indicating continuous development. Ostracod and diatom analyses indicate a lowering water level with higher salinities and rich aquatic vegetation. Mesorheophilic ostracod species along with tychoplanktic diatom taxa point to flowing waters and turbulence at the lakeshore, presumably related to spring-fed streams originating from nearby highlands. Palynological results reveal a very diverse zonal vegetation pattern around the palaeolakeshore considering an area of investigation of approximately 50 × 75 m and a tessellated type of regional vegetation during the formation of the archaeological horizons. On topographically lower elevated areas, birch groves and taxa favouring wet, marshy conditions such as Cyperaceae, indicative of terrestrialization, were predominating, while other stands of this transitional phase reveal a very dry, grass-dominated steppe woodland favouring a rich wildlife with a striking number of megaherbivores. Our results suggest that the lithological differences of the ‘Spear Horizon’ layers containing the archaeological finds were due to their respective topographical situation and that the layers were deposited almost simultaneously during the beginning of the lake level drop. Human activities seem to have concentrated in sparsely vegetated areas along the palaeolakeshore, rather than in areas of adjacent denser birch swamp forest stands.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 3","pages":"440-458"},"PeriodicalIF":2.2,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12619","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49536103","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":"Obliquity-driven mountain permafrost-related fluvial magnetic susceptibility cycles in the Quaternary mid-latitude long-term (2.5 Ma) fluvial Maros Fan in the Pannonian Basin","authors":"Zoltán Püspöki,&nbsp;Philip L. Gibbard,&nbsp;László Ferenc Kiss,&nbsp;Richard W. McIntosh,&nbsp;Edit Thamó-Bozsó,&nbsp;Zita Krassay,&nbsp;Bálint Szappanos,&nbsp;Vera Maigut,&nbsp;Péter Kovács,&nbsp;Dominik Karácsony,&nbsp;Ferenc Stercel,&nbsp;Ferenc Visnovitz,&nbsp;Krisztina Demény,&nbsp;László Bereczki,&nbsp;Teodóra Szőcs,&nbsp;Ágnes Rotár-Szalkai,&nbsp;Tamás Fancsik","doi":"10.1111/bor.12618","DOIUrl":"10.1111/bor.12618","url":null,"abstract":"<p>Magnetic susceptibility (MS) of the Quaternary long-term mid-latitude Maros fluvial fan (Pannonian Basin) was recorded to understand the stratigraphical features of source-proximal fluvial depositional settings. Three fully cored 500-m-deep boreholes were sampled at 0.5-m intervals; low-field and frequency dependent MS were measured, and complementary hysteresis and SEM-EDAX investigations were performed on selected samples. Logged susceptibility data were also used to log correlations established by a simultaneous comparison of wireline log and laboratory measurements. Time-series analyses of the susceptibility records reveal a ~41-ka and ~100-ka cyclicity. Towards the source-distal sections the intensity of the ~41-ka cycles decreases, while that of the ~100-ka cycles remains strong. Stratigraphical and spectral similarities were observed between the Maros fluvial fan and Chinese loess records; however, based on complementary magnetic data, the magnetic phase of the Maros Fan sections is related to the detrital magnetite that originates from the catchment during early postglacial permafrost degradations. The amplification of the ~41-ka cycles can be attributed to the very high susceptibility values in source-proximal settings and to the special stratigraphical feature of the distributive fluvial systems. This comprises the increased avulsion frequency on the fluvial fans in ‘glacial recession periods’, in concert with the ‘early postglacial’ occurrence of the permafrost-related magnetite originating from the catchment. As a local phenomenon, this is significant since it records the obliquity-driven variations in permafrost development in a catchment. However, fluvial and alluvial fans are widespread depositional landforms within the Eurasian mountain range and were possibly the same during the Quaternary deglaciations. Thus, obliquity-driven magnetic susceptibility variations in source-proximal fan deposits attached or adjacent to regions of loess deposition should also be considered when scanning for potential source material of aeolian deposits.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 3","pages":"402-426"},"PeriodicalIF":2.2,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12618","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43714572","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":"Depositional history of peatland pines (Pinus sylvestris L.) in NW Enontekiö, Finnish Lapland: implications for Middle Holocene drought and temperature fluctuations","authors":"Samuli Helama,&nbsp;Hannu Herva,&nbsp;Joonas Uusitalo,&nbsp;Andy Moir,&nbsp;Kari Mielikäinen,&nbsp;Pekka Nöjd,&nbsp;Markku Oinonen,&nbsp;Raimo Sutinen","doi":"10.1111/bor.12616","DOIUrl":"10.1111/bor.12616","url":null,"abstract":"<p>High altitude and latitude findings of subfossil peatland pine trees were unearthed from the region of NW Finnish Lapland and dated by ¹⁴C and tree-ring methods. The depositional history of the trees illustrated two distinct peatland pine phases dated to Middle Holocene intervals 4900–4400 and 4100–3400 cal. a BC. It seems evident that both thermal and hydroclimatic fluctuations have played roles of varying importance in the establishment of this pine population and its demise. The presence of these pines, from a site ~60 km north of the coniferous timberline and conditions ~1 °C and 100 degree-days colder than those at the present-day timberline, concurs with previous studies demonstrating the association between the high-latitude summer-temperature cooling and circumpolar timberline retreat since the Middle Holocene due to Milankovitch forcing. On the other hand, the peatland pine recruitment was made possible by drier than present surface conditions during the previously reconstructed Middle Holocene drought anomaly (Hyvärinen-Alhonen event). Our data suggest this event was not continuous but reached its two-phase climax during the peatland pine phases, with an interruption of several centuries with moister surface conditions between 4400 and 4100 cal. a BC. The findings highlight the sensitivity of well-dated peatland tree assemblages in terms of recording past climatic evolution and events and the need for new collections from north and south Fennoscandia and the Baltic region, for more detailed analyses over extended time intervals and regions.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 3","pages":"427-439"},"PeriodicalIF":2.2,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12616","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44967077","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":"Timing and maximum flood level of the Early Holocene glacial lake Nedre Glomsjø outburst flood, Norway","authors":"Fredrik Høgaas,&nbsp;Louise Hansen,&nbsp;Ivar Berthling,&nbsp;Martin Klug,&nbsp;Oddvar Longva,&nbsp;Helle Daling Nannestad,&nbsp;Lars Olsen,&nbsp;Anders Romundset","doi":"10.1111/bor.12615","DOIUrl":"10.1111/bor.12615","url":null,"abstract":"<p>This study discusses the timing and maximum flood level of the Nedre Glomsjø outburst flood, Norway, based on sediment records retrieved from 15 bog and lake basins located close to the purported maximum flooded level. The sediment records in 12 of the basins consist of a distinct light-coloured silty bed that is correlated to the outburst-flood-deposited ‘Romerike Silt Bed’ identified elsewhere in the region. The silt bed is recorded in basins up to a certain elevation and is absent above this level. The new maximum flood level inferred from the basin sediment records exceeds the established landform-induced palaeostage indicators by 5–10 m. The data indicate a higher maximum flood level and larger inundation area than previously suggested and highlight the importance of acquiring a wide range of geological data when reconstructing palaeofloods. Radiocarbon dates of terrestrial macrofossils found stratigraphically above and below the Romerike Silt Bed suggest that the glacial lake Nedre Glomsjø outburst flood occurred between 10.5 and 10.3 cal. ka BP. The new and well-constrained timing of the outburst flood is beneficial for reconstructing regional deglaciation and provides a precise age for the Romerike Silt Bed chronostratigraphical marker, which is of value for studies in SE Norway and adjacent regions.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 3","pages":"295-313"},"PeriodicalIF":2.2,"publicationDate":"2023-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12615","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45591866","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":"Sedimentary architecture and glacial hydrodynamic significance of the stratified Oak Ridges Moraine, southern Ontario, Canada","authors":"David R. Sharpe,&nbsp;Hazen A. J. Russell","doi":"10.1111/bor.12612","DOIUrl":"10.1111/bor.12612","url":null,"abstract":"<p>High-quality subsurface data provide new insights into the formation of Oak Ridges Moraine (ORM), an ~80 km³ sequence of stratified meltwater deposits resting &gt;200 m above adjacent Lake Ontario. The ORM sedimentary succession comprises a three-part regional architecture: (i) ~north–south channel sand–gravel; (ii) channel-capping rhythmites; and (iii) east–west ridge sediments. The ORM depositional sequence overlies a regional unconformity with a cross-cutting channel network resulting from ~north–south meltwater floods that transitioned progressively (falling stage) from a ~NNE to ENE flow direction (parallels Lake Ontario depression). Seismic profiles delineate the channels and channel fill characteristics of bank-to-bank channel sedimentation of thick gradational gravel–sand–mud sequences. Channel-capping mud (~100–236 rhythmites) within multiple channels beneath the ORM landform mark a widespread interval of low-energy, seasonally controlled subglacial pond deposition. During this quiescent period ice-sheet thickness adjusted to flood-induced stretching/thinning and re-profiled slopes. New ice gradients led to east–west flow and deposition of the overlying third element, a sequence of high-energy confined esker–fan sediments along ORM ridge. Close, sequential timing (~329 varve years) of channel, basin and ridge-forming architectural elements supports naming this assemblage the ORM formation. Proposed ORM floods are analogous to Icelandic jökulhlaups based on the size, geometry and sedimentology. The observed rhythmite interval between flood events represents a short period (~236 years) of regional meltwater storage prior to east–west ORM flooding. The ORM channel and overlying esker-fan sediment ridge represent two closely timed meltwater drainage events rather than formation by coalescing ice streams. The scale and timing of the ORM flood events are linked to rapid sea-level rise, ~13.5 ka BP. This high-resolution ORM sedimentological record may provide insights into depositional and glaciogenic controls of other large, stratified moraines. The ORM data indicate deposition in response to hydrodynamic events (outbreak floods, re-profiled ice) rather than direct climate forcing.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 3","pages":"341-380"},"PeriodicalIF":2.2,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12612","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49486053","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 Langeland Fault System unravelled: Quaternary fault reactivation along an elevated basement block between the North German and Norwegian–Danish basins","authors":"Niklas Ahlrichs,&nbsp;Christian Hübscher,&nbsp;Theis Raaschou Andersen,&nbsp;Jonas Preine,&nbsp;Laura Bogner,&nbsp;Wiebke Schäfer","doi":"10.1111/bor.12614","DOIUrl":"10.1111/bor.12614","url":null,"abstract":"<p>The reactivation of faults and possible impact on barrier integrity marks a critical aspect for investigations on subsurface usage capabilities. Glacial isostatic adjustments, originating from repeated Quaternary glaciations of northern Europe, cause tectonic stresses on pre-existing fault systems and structural elements of the North German and Norwegian–Danish basins. Notably, our current understanding of the dynamics and scales of glacially induced fault reactivation is rather limited. A high-resolution 2D seismic data set recently acquired offshore northeastern Langeland Island allows the investigation of a fault and graben system termed the Langeland Fault System. Seismo-stratigraphic interpretation of reflection seismic data in combination with diffraction imaging unravels the spatial character of the Langeland Fault System along an elevated basement block of the Ringkøbing–Fyn High. In combination with sediment echosounder data, the data set helps to visualize the continuation of deep-rooted faults up to the sea floor. Initial Mesozoic faulting occurred during the Triassic. Late Cretaceous inversion reactivated a basement fault flanking the southern border of the elevated basement block of the Ringkøbing–Fyn High while inversion is absent in the Langeland Fault System. Here, normal faulting occurred in the Maastrichtian–Danian. We show that a glacial or postglacial fault reactivation occurred within the Langeland Fault System, as evident by the propagation of the faults from the deeper subsurface up to the sea floor, dissecting glacial and postglacial successions. Our findings suggest that the Langeland Fault System was reactivated over a length scale of a minimum of 8.5 km. We discuss the causes for this Quaternary fault reactivations in the context of glacially induced faulting and the present-day stress field. The combination of imaging techniques with different penetration depths and vertical resolution used in this study is rarely realized in the hinterland. It can therefore be speculated that many more inherited, deep-rooted faults were reactivated in Pleistocene glaciated regions.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 3","pages":"381-401"},"PeriodicalIF":2.2,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12614","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47006714","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":"Landsystem analysis of a tropical moraine-dammed supraglacial lake, Llaca Lake, Cordillera Blanca, Perú","authors":"Rodrigo Alberto Narro Pérez,&nbsp;Carolyn H. Eyles,&nbsp;Rebecca E. Lee,&nbsp;Luzmila Dàvila Röller,&nbsp;John C. Maclachlan","doi":"10.1111/bor.12611","DOIUrl":"10.1111/bor.12611","url":null,"abstract":"<p>Tropical glaciers of the Cordillera Blanca, Perú are rapidly thinning and retreating as a result of climate warming. The retreat of these glaciers along narrow linear bedrock valleys has increased the number and size of moraine-dammed glacial lakes formed in the valleys. This study aims to identify the geomorphological and sedimentological characteristics of an enlarging moraine-dammed supraglacial lake (Llaca Lake) in the Cordillera Blanca. Field-based sedimentological observations and geomorphological mapping were combined with remotely sensed data and a photogrammetric model derived from aerial surveys by an uncrewed aerial vehicle to identify landform-sediment assemblages. The geomorphological and sedimentological characteristics of Llaca Lake are synthesized into three landsystem zones: Zone 1: distal portions of Llaca Lake and the latero-frontal moraine; Zone 2: the central zone of ice-cored hummocks; and Zone 3: the active glacier margin. These zones are differentiated based on the spatial distribution of landforms, sediments, and active geomorphological processes. This is the first study to describe the landform-sediment assemblages in a tropical moraine-dammed supraglacial lake system and provides a framework for further landsystem element analysis of these growing supraglacial lakes in rapidly deglaciating high-altitude environments.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"52 2","pages":"272-293"},"PeriodicalIF":2.2,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12611","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42143226","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}