Boreas最新文献

{"title":"Summer temperatures from the Middle Pleistocene site Schöningen 13 II, northern Germany, determined from subfossil chironomid assemblages","authors":"Sonja Rigterink,&nbsp;Kim J. Krahn,&nbsp;Bartosz Kotrys,&nbsp;Brigitte Urban,&nbsp;Oliver Heiri,&nbsp;Falko Turner,&nbsp;Andre Pannes,&nbsp;Antje Schwalb","doi":"10.1111/bor.12658","DOIUrl":"10.1111/bor.12658","url":null,"abstract":"<p>We present the first climatic and environmental reconstruction based on subfossil chironomid head capsules from the Middle Pleistocene Reinsdorf sequence, Schöningen, northern Germany, corresponding to Marine Isotope Stage 9e-a. The sequence is characterized by interglacial forest successions followed by alternating woodland and steppe phases. Higher levels of runoff formed lacustrine habitats during post-interglacial, cool steppe (woodland) phases. These were characterized by diverse chironomid assemblages with up to 27 chironomid morphotypes occurring simultaneously. Warmer forest phases were mostly void of chironomids when the site Schöningen 13 II fell dry owing to higher vegetational coverage and therefore lower runoff. Transitional periods between woodland and steppe phases show higher abundances of profundal, bottom-dwelling chironomid taxa, suggesting oligo-mesotrophic aquatic conditions, while steppe phases are dominated by shallow-lake taxa with higher tolerance to increasing productivity. We applied temperature inference models to the chironomid assemblages based on a Swiss–Norwegian and a Swiss–Norwegian–Polish chironomid–temperature calibration data set to reconstruct mean July air temperatures for the Reinsdorf sequence. The Swiss–Norwegian–Polish training set (TS) seems better suited owing to a longer temperature gradient and the presence of the dominant taxon, <i>Propsilocerus lacustris</i>-type, which is missing from the Swiss–Norwegian TS. In sections of the record with low taxon richness (Shannon index &lt;2) and a dominance of <i>P. lacustris</i>-type, indicating increased nutrient impact, summer temperatures may have been overestimated by the Swiss–Norwegian–Polish TS. In the other sections, the chironomid-based reconstructions based on the Swiss–Norwegian–Polish TS were in line with ostracod and plant remains-based temperature reconstructions, suggesting summer temperatures of the post-interglacial Reinsdorf oscillations between 16.5 and 22 °C. Our results show that summer air temperatures were lower during warmer, wetter transitional zones (−0.5–0.2 °C colder/warmer than today) and increasing during cooler, dry steppe phases (1 °C warmer than today), most likely caused by higher continentality.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 4","pages":"525-542"},"PeriodicalIF":2.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12658","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140700111","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":"Chironomidae-based inference model for mean July air temperature reconstructions in the eastern Baltic area","authors":"Varvara Bakumenko,&nbsp;Anneli Poska,&nbsp;Mateusz Płóciennik,&nbsp;Neringa Gasteviciene,&nbsp;Bartosz Kotrys,&nbsp;Tomi P. Luoto,&nbsp;Simon Belle,&nbsp;Siim Veski","doi":"10.1111/bor.12655","DOIUrl":"10.1111/bor.12655","url":null,"abstract":"<p>Here we present a new eastern Baltic Chironomidae training set (TS) containing 35 sites that was collected and merged with neighbouring published Finnish (82 lakes) and northern part of the Polish (nine lakes) TSs. Chironomidae, non-biting midges, are known to be strongly responsive to the July air temperature and are widely used to infer palaeotemperature. Several modern analogue-based TSs necessary for calibrating the relationships between mean July air temperature (MJAT) and chironomids are available for Europe. However, none of these is representative of the transitional climate typical for eastern Baltic (Estonia, Latvia, Lithuania). The Finno–Baltic–Polish TS contains 121 sites and covers a geographically continuous 70–50°N latitudinal and 7 °C (12.1–19.2 °C) MJAT gradient. Canonical correspondence analysis revealed that, among the tested environmental variables (pH, water depth, dissolved oxygen, MJAT), the MJAT explains the highest amount of variation, both for the eastern Baltic separately and the Finno–Baltic–Polish TSs. The weighted averaging–partial least squares-based cross-validation test reveals that the Finno–Baltic–Polish TS has a low root mean square error of prediction (0.7 °C) confirming the high reliability of the TS. The temperature optima of the taxa included in the new Finno–Baltic–Polish TS and widely used Swiss–Norwegian TS were examined. The observed dissimilarities can be attributed to the differences in the temperature ranges represented by the TS, the taxonomic identification level, the general cosmopolitan taxa distribution patterns and the influence of TS-specific geographic position, climatic or environmental conditions. The new Finno–Baltic–Polish TS adds to the knowledge on the modern distribution of Chironomidae taxa and widens the geographical area of reliable Chironomid-based MJAT reconstructions into the eastern European lowland.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 3","pages":"401-414"},"PeriodicalIF":2.4,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12655","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140387608","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":"Younger Dryas and Early Holocene ice-margin dynamics in northwest Russia","authors":"Benjamin M. Boyes,&nbsp;Danni M. Pearce,&nbsp;Lorna D. Linch,&nbsp;David J. Nash","doi":"10.1111/bor.12653","DOIUrl":"https://doi.org/10.1111/bor.12653","url":null,"abstract":"<p>The dynamics of the last Fennoscandian Ice Sheet (FIS) are relatively well constrained in the Nordic countries. Ice-sheet dynamics in NW Russia, however, are comparatively less well understood owing to the scale and resolution of existing studies. New large-scale glacial geomorphological datasets from NW Russia based on high-resolution remotely sensed imagery allow for an independent reassessment of the extent and dynamics of the FIS during the Younger Dryas and Early Holocene (<i>c.</i> 12.9–10 ka) in NW Russia. The reconstruction provides a more detailed link between geomorphological expressions of palaeoglaciation than previous proposals. Rather than a continuous Younger Dryas ice marginal zone (IMZ) stretching from Finland to northern Norway, the geomorphological signature of NW Russia reveals 14 IMZs that document discrete stationary ice-margin positions (possibly standstill and/or readvance events) during the overall retreat. The relative age sequence of the IMZs, supported by an updated numerical age database, suggests that they formed time-transgressively during the Younger Dryas and Early Holocene rather than contemporaneously. Moreover, specific landform assemblages reveal contrasting glacial landsystems in NW Russia: (i) a northern subpolar glacial landsystem; and (ii) a southern temperate glacial landsystem. The model presented herein provides robust empirical constraints for testing and validating numerical ice-sheet models and understanding ice-sheet responses to rapid climate change.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 3","pages":"376-400"},"PeriodicalIF":2.4,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12653","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141624343","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":"Patterns of glacio-isostatic adjustment in mainland Scotland: new data from western central Scotland, proximal to the zone of maximum rebound","authors":"David E. Smith,&nbsp;Callum R. Firth,&nbsp;James Rose","doi":"10.1111/bor.12650","DOIUrl":"https://doi.org/10.1111/bor.12650","url":null,"abstract":"<p>The results of geomorphological mapping and survey of Lateglacial and Holocene displaced shorelines in the Clyde estuary and around Loch Lomond, western central Scotland are described. On the basis of morphology, sedimentology, altitude and radiocarbon dating, four discrete shorelines are identified and are correlated with previously identified Scottish displaced shorelines. The shoreline formerly referred to as the Main Postglacial Shoreline is renamed the Menteith Shoreline. This body of data, combined with data on displaced shorelines for Scotland as a whole has been analysed using Gaussian quadratic trend surface analysis in order to determine the centre of glacio-isostatic displacement for each shoreline. These Gaussian models of palaeo-relative sea-level suggest that the zone of greatest displacement lay NNW of Loch Lomond in the Lateglacial then moved SSE to the region of Loch Lomond during the Holocene and the Clyde in the Late Holocene. The factors responsible for the movement of the zone of greatest uplift are discussed, including temporal variations in the ice-sheet thickness, variations in water load in the adjacent sea-lochs and neotectonic processes. Comparison is made with glacial isostatic adjustment (GIA) models. A sensitivity analysis has been carried out on the use of Gaussian trend surface analysis glacio-isostatic modelling and this is included in the research evaluation, and reported in full in the Supporting Information files, along with the raw data used throughout this study.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 2","pages":"262-281"},"PeriodicalIF":2.2,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12650","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140351705","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":"Multi-proxy palaeoenvironmental reconstruction of the Skagerrak from the Lateglacial to Middle Holocene","authors":"Emma Ownsworth,&nbsp;Matthias Moros,&nbsp;Jeremy Lloyd,&nbsp;Ole Bennike,&nbsp;Jørn Bo Jensen,&nbsp;Thomas Blanz,&nbsp;David Selby","doi":"10.1111/bor.12652","DOIUrl":"10.1111/bor.12652","url":null,"abstract":"<p>This study uses a multiproxy approach including the first use of ¹⁸⁷Os/¹⁸⁸Os, %C_37:4 biomarkers, carbonate content, sedimentological grain size, geochemical X-ray fluorescence and microfossil benthic foraminifera species combined with radiocarbon dating, measured on six cores from across the Skagerrak, in order to study the Lateglacial to Middle Holocene history of the area. A new chronostratigraphic framework is developed based on the appearance of specific benthic foraminifera species along with changes in carbonate/X-ray fluorescence and grain size data. This allowed the correlation of cores based on a series of radiocarbon dated tie points. Analysing the cores together reveals several events recorded in the Skagerrak including: (i) an increased freshwater input (bracketed between 13.3 and 11.3 cal. ka BP) signified by radiogenic ¹⁸⁷Os/¹⁸⁸Os values, high %C_37:4 values and an increase in sand content; (ii) the Glomma drainage event, signified by a sudden appearance of <i>Valvulineria</i> as well as higher %C_37:4; and (iii) the opening of the Danish Straits and English Channel leading to the development of modern-day conditions and circulation patterns in the Skagerrak, signified by the appearance of <i>Hyalinea balthica</i> and a fall in %C_37:4.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 3","pages":"360-375"},"PeriodicalIF":2.4,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12652","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139840181","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":"Re-investigation of the Bispingen palaeolake sediment succession (northern Germany) reveals that the Last Interglacial (Eemian) in northern-central Europe lasted at least ~15 000 years","authors":"Stefan Lauterbach,&nbsp;Frank H. Neumann,&nbsp;Rik Tjallingii,&nbsp;Achim Brauer","doi":"10.1111/bor.12649","DOIUrl":"10.1111/bor.12649","url":null,"abstract":"<p>Investigating past interglacial climatic and environmental changes can enhance our understanding of the natural rates and ranges of climate variability under interglacial boundary conditions. However, comparing past interglacial palaeoclimate records from different regions and archives is often complicated by differing and uncertain chronologies. For instance, the duration of the Last Interglacial in Europe is still controversial as southern European palaeoclimate records suggest a duration of ~16 500–18 000 years, while a length of only ~11 000 years in northern-central Europe was previously inferred from the analysis of partly annually laminated (varved) palaeolake sediments recovered at Bispingen, northern Germany. To resolve this discrepancy, we here present sediment microfacies, geochemistry and pollen data from a new sediment core from the Bispingen palaeolake sediment succession, covering the entire Last Interglacial (Eemian) and the earliest part of the Last Glacial (Weichselian). In particular, we provide evidence that the duration of the Last Interglacial at Bispingen must have been hitherto underestimated due to the investigation of an incomplete sediment core. Using microscopic varve counting and sedimentation rate estimates for non-varved sections on the new sediment core, we show that the Eemian in northern-central Europe probably lasted at least ~15 000 years, about 4000 years longer than previously thought. This new duration estimate is in much better agreement with results from southern European palaeoclimate records, clarifying the enigma of a steep trans-European vegetation gradient for several millennia at the end of the Last Interglacial.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 2","pages":"243-261"},"PeriodicalIF":2.2,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12649","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139843698","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":"Recent hummock establishment in the margin of a subarctic fen, Finnish Lapland","authors":"Olivia Kuuri-Riutta,&nbsp;Elmiina Pilkama,&nbsp;Susanna Salminen-Paatero,&nbsp;Camille Vögeli,&nbsp;Edward A. D. Mitchell,&nbsp;Annalea Lohila,&nbsp;Eeva-Stiina Tuittila,&nbsp;Minna Väliranta","doi":"10.1111/bor.12651","DOIUrl":"10.1111/bor.12651","url":null,"abstract":"<p>Northern fens, that host unique biota and form a remarkable carbon stock, are sensitive to changes in the moisture balance and, therefore, may be strongly affected by climatic fluctuations. However, long-term monitoring and palaeoecological studies of fens are relatively rare and, as a result, their responses to past and current climatic fluctuations are poorly known. In this study, we examined the recent vegetation change as well as changes in testate amoeba communities in the mire margin of a subarctic fen in Finnish Lapland with four peat profiles. Testate amoebae were used as indicators of past fluctuations in water table depth. The vegetation showed a drastic shift from sedge-dominated fen to <i>Sphagnum</i>-dominated communities during the late 20th and the early 21st centuries. This shift was accompanied by a turnover in the testate amoeba community. Testate amoeba-based water table reconstructions indicated recent drying. This may be due to the lowering of the water table either from accelerated <i>Sphagnum</i> increment or enhanced evaporation. The observed hummock establishment concurs with the documented hemisphere-wide expansion trend of hummock communities in fens. This change may strengthen the carbon sink and storage capacity of these peatlands, which could be viewed as a welcome negative feedback process to the ongoing climate warming. However, the change also poses a threat to biodiversity since fens are not only species-rich habitats but are also endangered ecosystems.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 2","pages":"282-295"},"PeriodicalIF":2.2,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12651","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139870976","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":"Exploring the potential of rock surface luminescence from glacial sediments: dating and transport history","authors":"Eike F. Rades,&nbsp;Reza Sohbati,&nbsp;Helena Alexanderson,&nbsp;Mayank Jain,&nbsp;Andrew S. Murray","doi":"10.1111/bor.12648","DOIUrl":"https://doi.org/10.1111/bor.12648","url":null,"abstract":"<p>The dating of moraine deposits can present challenges to standard geochronological methods; terrestrial cosmogenic nuclide (TCN), sediment luminescence and radiocarbon dating may suffer from problems of incomplete resetting (by inheritance, intermittent cover/exposure, transport under unfavourable conditions) and/or a lack of suitable (organic) material. Rock surface luminescence burial dating (RSLBD) offers an alternative approach with considerable potential in dating moraines. In RSLBD, large cobbles/boulders are targeted, rather than smaller grains usually used in luminescence dating. The age limit of RSLBD is much higher than that of radiocarbon dating, and rocks are much more readily available than organic material. In contrast to TCN dating, the effect of exposure prior to deposition can be measured. In this study, we sampled a broad selection of primarily granitic boulders of various sizes and shapes (e.g. different degrees of roundness and sphericity) from the Vimmerby Moraine, a prominent and accessible feature in southern Sweden dated using TCN to 14.4±0.9 ka. Our study was designed to test whether morphological characteristics can be used to discriminate in favour of the most light-exposed boulders and minimize measurements of non-exposed boulders. As expected, not all RSLBD ages can be attributed to the same depositional event, but the majority of the resulting ages provide a mean age of 13.0±1.5 ka, consistent with the cosmogenic nuclide dating of the Vimmerby Moraine. Despite the apparently successful TCN study, the luminescence–depth profiles measured in the buried surfaces of the sampled clasts indicate that &gt;50% of these moraine boulders were exposed to light (and cosmic radiation) before final deposition, implying some (presumably small) TCN inheritance; seven of the 16 boulders identified as light exposed were sufficiently bleached to be useful for RSLBD. These results and their implications in regard to transport and deposition of the sampled cobbles are critically discussed and evaluated.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 2","pages":"227-242"},"PeriodicalIF":2.2,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12648","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140351639","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 relationship between the loess stratigraphy in the Vojvodina region of northern Serbia and the Saalian and Rissian Stage glaciations – a review","authors":"Slobodan B. Marković,&nbsp;Philip D. Hughes,&nbsp;Randall Schaetzl,&nbsp;Philip L. Gibbard,&nbsp;Qingzhen Hao,&nbsp;Milica G. Radaković,&nbsp;Jef Vandenberghe,&nbsp;Igor Obreht,&nbsp;György Sipos,&nbsp;Christian Laag,&nbsp;Milivoj B. Gavrilov,&nbsp;Aleksandar Antić,&nbsp;Rastko S. Marković,&nbsp;Petar Krsmanović,&nbsp;Kaja Fenn,&nbsp;Tin Lukić,&nbsp;Zoran M. Perić","doi":"10.1111/bor.12646","DOIUrl":"10.1111/bor.12646","url":null,"abstract":"<p>The regional loess stratigraphy in the Vojvodina region, in the southeastern Carpathian Basin, has often been successfully correlated to the global palaeoclimate. This is a quasi-continuous sedimentary record that provides detailed environmental reconstruction during the last four glacial/interglacial cycles. In this study, we present a standardized loess stratigraphy and illustrate how it correlates with the marine oxygen isotope and Chinese loess stratigraphical records. We argue that the loess stratigraphy in Vojvodina region is an important link in the integration of European terrestrial stratigraphical schemes and the deep-sea stratigraphical model. We highlight how the loess record can better illustrate terrestrial environmental change through multiple glacial cycles than other records, such as glacial records. The investigated loess record enables direct links to be made between the loess sediments and their glacial sources. This reveals evidence of glaciations during every glacial cycle of the Saalian Stage complex, equivalent to Marine Isotope Stage (MIS) 10, 8 and 6. Therefore, Serbian loess has the potential to provide a direct link between terrestrial glaciations and wider records of global climate change, which is an enigma for many other continental records. These loess records display a strong relationship with the intensity of European glaciations during different glacial cycles. Loess sedimentation rates are highest in the most intensive European glaciation of the Saalian complex (MIS 6) and much lower during the weaker ‘missing’ glaciations equivalent to MIS 8 and 10. A key observation from the Vojvodina loess is the gradual increase in interglacial aridity through the late Middle Pleistocene. The explanation for the progressively increasing aridity in the investigated region at this time is still unclear. However, this trend is consistent with the idea of the Saalian complex as representing a 400 ka mega glacial cycle modulated by shorter classic 100 ka glacial cycles.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 4","pages":"577-592"},"PeriodicalIF":2.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12646","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139526083","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 integrated geological characterization of the Mid-Pleistocene to Holocene geology of the Sørlige Nordsjø II offshore wind site, southern North Sea","authors":"Hannah E. Petrie,&nbsp;Christian H. Eide,&nbsp;Haflidi Haflidason,&nbsp;Jo Brendryen,&nbsp;Timothy Watton","doi":"10.1111/bor.12647","DOIUrl":"10.1111/bor.12647","url":null,"abstract":"<p>Subsurface deposits in recently glaciated marine areas are highly heterogeneous, representing a range of glacial and postglacial environments and processes including glacitectonism, overconsolidation, fluvial and lacustrine deposition, and transgression. These heterogeneities are often linked to variations in engineering properties, with important implications for the design and installation of offshore wind infrastructure. In this study we present an integrated geological characterization of the Sørlige Nordsjø II offshore wind site, located in waters of 50–70 m depth along the southern border of the Norwegian North Sea, focusing on the evolution of the area's depositional setting during the late Quaternary period and its implications for offshore wind development. We integrate interpretations from a marine geological data set acquired in 2022 with legacy 3D seismic data and a review of the current understanding of the southern North Sea's complex glacial history. A preliminary ground model and accompanying risk map for the site is presented with five main geological units: (i) homogeneous and layered marine sands covering most of the site, with patchy distribution and coarser-grained deposits in the east; (ii) buried, layered channel deposits containing organic material and possible associated shallow gas; (iii) buried, stiff glacilacustrine clay deposits; (iv) a buried, layered, glacitectonized unit incised by tunnel valleys, with a sandy marine infill; and (v) mounded tills and glacitectonized deposits containing boulders, exposed to shallowly buried in the east. Salt diapirism and gas migration were also found to be important potential geohazards at the site. Three-dimensional seismic attribute maps were found to be a powerful aid to understanding the distribution and genesis of seismic facies identified on 2D high-resolution sub-bottom profiles. This type of data integration is an under-utilized methodology for generating detailed preliminary ground models, which can inform more cost-effective site survey and early foundation concept planning at geologically complex offshore wind sites.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 2","pages":"186-226"},"PeriodicalIF":2.2,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12647","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139612220","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}