In this study, the morphotectonic features of the Yenişehir pull-apart basin in Bursa in northwestern Turkey were analysed. The faults in the region are the most important structural elements that characterize the morphology of the Yenişehir pull-apart basin. The aim of this study is to show the deformation effects of these active faults on the geomorphology with some basic morphometric indices. The morphotectonic features were evaluated using the hypsometric curve and hypsometric integral (Hi), drainage basin asymmetry (the asymmetry factor (AF) and the transverse topographic symmetry factor (T)), river length gradient index, mountain front sinuosity, and valley floor ratio. The morphometric indices that play an important role in the analysis of catchment areas are the Hi, AF, and T indices, which indicate tilting and erosion activities. According to the results of the hypsometric curve and hypsometric integral, the Yenişehir Basin is a young basin with a uniform topography as expected in an active pull-apart basin formed by faulting in the Quaternary. The relative tectonic activity index (Iat) of the study area was calculated using the values of hypsometric integral, transverse topographic symmetry factor, asymmetry factor, mountain front sinuosity, valley floor ratio and stream length gradient index. The Iat values indicate the tectonic activity of the basin from Pliocene to Recent. Three different tectonic classes were identified in the study area. These are class 1 (high relative tectonic activity), class 2 (moderate relative tectonic activity), and class 3 (low relative tectonic activity). The Iat classification data show that the impact of tectonic activity on the geomorphology is lower in the Iat class 3 indices than in the others. The Iat data show high tectonic activity in the region where active faults of the North Anatolian Fault Zone southern branch are located.
{"title":"Tectonic evolution of Bursa Yenişehir Basin, Turkey from the Neogene to the Quaternary using a morphotectonic approach","authors":"K. Ömer Taş, Günay Beyhan, H. Haluk Selim","doi":"10.1111/bor.12671","DOIUrl":"https://doi.org/10.1111/bor.12671","url":null,"abstract":"<p>In this study, the morphotectonic features of the Yenişehir pull-apart basin in Bursa in northwestern Turkey were analysed. The faults in the region are the most important structural elements that characterize the morphology of the Yenişehir pull-apart basin. The aim of this study is to show the deformation effects of these active faults on the geomorphology with some basic morphometric indices. The morphotectonic features were evaluated using the hypsometric curve and hypsometric integral (<i>H</i><sub>i</sub>), drainage basin asymmetry (the asymmetry factor (<i>A</i><sub>F</sub>) and the transverse topographic symmetry factor (<i>T</i>)), river length gradient index, mountain front sinuosity, and valley floor ratio. The morphometric indices that play an important role in the analysis of catchment areas are the <i>H</i><sub>i</sub>, <i>A</i><sub>F</sub>, and <i>T</i> indices, which indicate tilting and erosion activities. According to the results of the hypsometric curve and hypsometric integral, the Yenişehir Basin is a young basin with a uniform topography as expected in an active pull-apart basin formed by faulting in the Quaternary. The relative tectonic activity index (Iat) of the study area was calculated using the values of hypsometric integral, transverse topographic symmetry factor, asymmetry factor, mountain front sinuosity, valley floor ratio and stream length gradient index. The Iat values indicate the tectonic activity of the basin from Pliocene to Recent. Three different tectonic classes were identified in the study area. These are class 1 (high relative tectonic activity), class 2 (moderate relative tectonic activity), and class 3 (low relative tectonic activity). The Iat classification data show that the impact of tectonic activity on the geomorphology is lower in the Iat class 3 indices than in the others. The Iat data show high tectonic activity in the region where active faults of the North Anatolian Fault Zone southern branch are located.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 1","pages":"125-139"},"PeriodicalIF":2.4,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12671","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143112289","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}
Eirini Anagnostou, Johan Linderholm, Kerstin Lidén
The middle of the first millennium AD in Sweden witnessed significant changes in the archaeological record, prompting various discussions about the underlying causes. This paper reviews the research developments surrounding the global climate cooling, which was caused by severe volcanic eruptions in AD 536/540 and is referred to as the Late Antique Little Ice Age or Fimbulwinter, and its potential impacts, with a specific focus on Swedish Iron Age societies, drawing upon published climatic and archaeological data. Furthermore, it discusses the research gaps that impede a comprehensive understanding of the potential relationship between the AD 536/540 event and socioeconomic changes in Iron Age Sweden. Additionally, it suggests that isotopic analysis will offer additional insights and help bridge the research gap.
{"title":"The AD 536/540 climate event in Sweden – a review","authors":"Eirini Anagnostou, Johan Linderholm, Kerstin Lidén","doi":"10.1111/bor.12672","DOIUrl":"https://doi.org/10.1111/bor.12672","url":null,"abstract":"<p>The middle of the first millennium AD in Sweden witnessed significant changes in the archaeological record, prompting various discussions about the underlying causes. This paper reviews the research developments surrounding the global climate cooling, which was caused by severe volcanic eruptions in AD 536/540 and is referred to as the Late Antique Little Ice Age or Fimbulwinter, and its potential impacts, with a specific focus on Swedish Iron Age societies, drawing upon published climatic and archaeological data. Furthermore, it discusses the research gaps that impede a comprehensive understanding of the potential relationship between the AD 536/540 event and socioeconomic changes in Iron Age Sweden. Additionally, it suggests that isotopic analysis will offer additional insights and help bridge the research gap.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"54 1","pages":"1-13"},"PeriodicalIF":2.4,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143112185","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}
Kim J. Krahn, Brigitte Urban, Sylvia Pinkerneil, David J. Horne, Mario Tucci, Andreas Koutsodendris, Antje Schwalb
The Middle Pleistocene Reinsdorf sequence at the Lower Palaeolithic sites of Schöningen offers the opportunity to reconstruct a rarely well-preserved post-Holsteinian environmental transition from an interglacial into a glacial phase along with its highly dynamic interjacent climatic oscillations. Combining biological proxies, element composition and stable isotope ratios of two lakeshore sequences at excavation site 13 II, we demonstrate repeated variations in climate, hydrology and catchment vegetation cover. New ostracod-based quantitative mean summer and winter air temperature reconstructions with the Mutual Ostracod Temperature Range (MOTR) method provide the first detailed information about the temperature evolution. The interglacial temperature maximum, probably corresponding to Marine Isotope Stage 9e, is followed by a first dry phase and, during the younger part of the Reinsdorf sequence, by a second dry period. Both were marked by lower precipitation/evaporation ratios, reduced vegetation cover in the catchment and increased surface inflows from springs. Temperature reconstructions of these two steppe (open woodland) phases yield very narrow ranges for mean January (−4–0 °C) and July (+17–19 or +17–21 °C) air temperatures, demonstrating that, while summers were similar to those of today, winters were at least 1 °C colder, hinting at a more pronounced continental climate. Precise temperature estimates for the interjacent woodland and steppe (woodland) phase are hindered by generally wider ranges produced by the MOTR method (January mean −4–3 °C, July mean +15–21 °C). The development of a more extensive vegetation cover, reducing surface runoff and erosion in favour of increased river and groundwater discharge, as indicated by a shift in microfossil and stable isotope records, suggests generally more humid climates with higher precipitation/evaporation ratios as well as reduced seasonal temperature variations.
舍宁根下层旧石器时代遗址的中更新世莱恩斯多夫序列为重建保存完好的后荷尔斯泰因环境从间冰期向冰川期的过渡及其高度动态的相邻气候振荡提供了机会。结合 13 II 号发掘地点两个湖岸序列的生物代用指标、元素组成和稳定同位素比值,我们展示了气候、水文和流域植被覆盖的反复变化。利用相互梭形目动物温度范围(MOTR)方法,基于新的梭形目动物定量重建了夏季和冬季平均气温,首次提供了有关气温演变的详细信息。冰期温度最高值(可能与海洋同位素阶段 9e 相对应)之后是第一个干燥期,在莱因斯多夫序列的较年轻部分则是第二个干燥期。这两个时期的特点都是降水/蒸发比降低、集水区植被覆盖减少以及地表泉水流入量增加。这两个草原(疏林地)阶段的气温重建结果显示,1 月平均气温(-4-0 °C)和 7 月平均气温(+17-19 或 +17-21 °C)的范围很窄,这表明,虽然夏季与今天的气温相似,但冬季至少要冷 1 °C,暗示着大陆性气候更加明显。对相邻的林地和草原(林地)阶段气温的精确估算受到 MOTR 方法产生的较宽范围(一月平均气温-4-3 °C,七月平均气温+15-21 °C)的影响。微化石和稳定同位素记录的变化表明,植被覆盖面积扩大,地表径流和侵蚀减少,河流和地下水排放量增加,这表明气候总体上更加湿润,降水/蒸发比增加,季节性温度变化减少。
{"title":"Temperature and palaeolake evolution during a Middle Pleistocene interglacial–glacial transition at the Palaeolithic locality of Schöningen, Germany","authors":"Kim J. Krahn, Brigitte Urban, Sylvia Pinkerneil, David J. Horne, Mario Tucci, Andreas Koutsodendris, Antje Schwalb","doi":"10.1111/bor.12670","DOIUrl":"10.1111/bor.12670","url":null,"abstract":"<p>The Middle Pleistocene Reinsdorf sequence at the Lower Palaeolithic sites of Schöningen offers the opportunity to reconstruct a rarely well-preserved post-Holsteinian environmental transition from an interglacial into a glacial phase along with its highly dynamic interjacent climatic oscillations. Combining biological proxies, element composition and stable isotope ratios of two lakeshore sequences at excavation site 13 II, we demonstrate repeated variations in climate, hydrology and catchment vegetation cover. New ostracod-based quantitative mean summer and winter air temperature reconstructions with the Mutual Ostracod Temperature Range (MOTR) method provide the first detailed information about the temperature evolution. The interglacial temperature maximum, probably corresponding to Marine Isotope Stage 9e, is followed by a first dry phase and, during the younger part of the Reinsdorf sequence, by a second dry period. Both were marked by lower precipitation/evaporation ratios, reduced vegetation cover in the catchment and increased surface inflows from springs. Temperature reconstructions of these two steppe (open woodland) phases yield very narrow ranges for mean January (−4–0 °C) and July (+17–19 or +17–21 °C) air temperatures, demonstrating that, while summers were similar to those of today, winters were at least 1 °C colder, hinting at a more pronounced continental climate. Precise temperature estimates for the interjacent woodland and steppe (woodland) phase are hindered by generally wider ranges produced by the MOTR method (January mean −4–3 °C, July mean +15–21 °C). The development of a more extensive vegetation cover, reducing surface runoff and erosion in favour of increased river and groundwater discharge, as indicated by a shift in microfossil and stable isotope records, suggests generally more humid climates with higher precipitation/evaporation ratios as well as reduced seasonal temperature variations.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 4","pages":"504-524"},"PeriodicalIF":2.4,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12670","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141660000","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}
Daniel Gademann, Nino Ustiashvili, Luka Adikashvili, Levan Navrozashvili, Nathaniel Erb-Satullo, W. Marijn van der Meij, Giorgi Kirkitadze, Tiiu Koff, Mikheil Elashvili, Helmut Brückner, Hannes Laermanns
Lake Paravani, located on the volcanic Javakheti Plateau in the central part of the Lesser Caucasus at 2073 m a.s.l., forms a unique geo-bio-archive for palaeoenvironmental reconstructions in this remote region. Based on sediment cores from the southwestern part of the lake we expand the existing palynological and sedimentological records beyond the Last Glacial Maximum (LGM). For the first time, it is possible to reconstruct the palaeoenvironment in this part of the Lesser Caucasus back to c. 28 cal. ka BP. Our study shows that until 16 cal. ka BP glacial conditions dominated (Phase I) in the region; there is, however, proof that the lake already existed during the LGM. In the following transitional Phase II from 16 until 6 cal. ka BP, cold and arid conditions with sparse steppe vegetation and a lowered lake level prevailed. Around 10 cal. ka BP, tree pollen started to expand while herbaceous pollen, especially Chenopodiaceae, declined. In Phase III, since 6 cal. ka BP, mixed forest probably represented the Holocene climatic optimum. Fluctuating lake levels indicate shifting climatic conditions. The minor changes of arboreal pollen hin the uppermost part of Phase II may be an indication of human activity. The more humid, vegetation-rich environment and mild climate around 4.5–2 cal. ka BP correlate with the expansion of the Late Bronze Age settlements in this area (from ~3.5 cal. ka BP/~1.5 ka BC). The proliferation of sites on the plateau, along with even higher-altitude sites possibly dating to the same period, may indicate that this climate amelioration played an important role in enabling more sustained human occupation. The results extend the record on Lake Paravani by several millennia beyond the LGM and complement the palaeo-lake reconstructions of the wider region, e.g. at Lake Van (Türkiye) or Lake Sevan (Armenia).
{"title":"The Lake Paravani archive – a contribution to the late Quaternary landscape evolution of the Lesser Caucasus (Georgia)","authors":"Daniel Gademann, Nino Ustiashvili, Luka Adikashvili, Levan Navrozashvili, Nathaniel Erb-Satullo, W. Marijn van der Meij, Giorgi Kirkitadze, Tiiu Koff, Mikheil Elashvili, Helmut Brückner, Hannes Laermanns","doi":"10.1111/bor.12669","DOIUrl":"10.1111/bor.12669","url":null,"abstract":"<p>Lake Paravani, located on the volcanic Javakheti Plateau in the central part of the Lesser Caucasus at 2073 m a.s.l., forms a unique geo-bio-archive for palaeoenvironmental reconstructions in this remote region. Based on sediment cores from the southwestern part of the lake we expand the existing palynological and sedimentological records beyond the Last Glacial Maximum (LGM). For the first time, it is possible to reconstruct the palaeoenvironment in this part of the Lesser Caucasus back to <i>c.</i> 28 cal. ka BP. Our study shows that until 16 cal. ka BP glacial conditions dominated (Phase I) in the region; there is, however, proof that the lake already existed during the LGM. In the following transitional Phase II from 16 until 6 cal. ka BP, cold and arid conditions with sparse steppe vegetation and a lowered lake level prevailed. Around 10 cal. ka BP, tree pollen started to expand while herbaceous pollen, especially Chenopodiaceae, declined. In Phase III, since 6 cal. ka BP, mixed forest probably represented the Holocene climatic optimum. Fluctuating lake levels indicate shifting climatic conditions. The minor changes of arboreal pollen hin the uppermost part of Phase II may be an indication of human activity. The more humid, vegetation-rich environment and mild climate around 4.5–2 cal. ka BP correlate with the expansion of the Late Bronze Age settlements in this area (from ~3.5 cal. ka BP/~1.5 ka BC). The proliferation of sites on the plateau, along with even higher-altitude sites possibly dating to the same period, may indicate that this climate amelioration played an important role in enabling more sustained human occupation. The results extend the record on Lake Paravani by several millennia beyond the LGM and complement the palaeo-lake reconstructions of the wider region, e.g. at Lake Van (Türkiye) or Lake Sevan (Armenia).</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 4","pages":"655-672"},"PeriodicalIF":2.4,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12669","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141701629","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}
Josh R. Leigh, Richard S. Jones, Chris R. Stokes, David J. A. Evans, J. Rachel Carr, Liss M. Andreassen
Here we present the first Lateglacial and Holocene glacial history from Rotsunddalen, northern Troms and western Finnmark county, northern Norway, based on both relative and numerical moraine dating using Schmidt hammer, soil chronosequencing and terrestrial cosmogenic nuclide dating. We combine these chronological data with a regional map of the glacial geomorphology to hypothesize key events in the glacial history from around 14 ka to present. Our reconstruction shows that, following deglaciation of the main ice sheet across central Troms and Finnmark, mountain glaciers were terminating on land, close to the coast, between around 12.1 and 10.6 ka. Continued recession of the main Fennoscandian Ice Sheet margin towards the SE led to the isolation of several large plateau icefields and outlet glaciers that generated moraines at around 10.2–9.2 ka, which we ascribe to the Erdalen Event, and 8.4–8.2 ka, which is broadly contemporaneous with the 8.2 ka cold event. Although the latter corresponds with the Scandinavian Finse Event, very few moraines have been dated to this time and we therefore view it as a tentative hypothesis for future work to test. During the Holocene Thermal Maximum (~6.6 to 6.3 ka) most (if not all) glaciers in the region disappeared, but then regrew during the Neoglaciation and produced large moraines dated to around 4.7 ka that lie a few hundred metres distal to the prominent Little Ice Age moraines (previously dated to AD 1810s–1870s). Given the limitations of our dating approach, the preservation of moraines dated to this period in northern Norway also warrants further investigation. We also highlight that terrestrial cosmogenic nuclide dating of the moraines is not consistent with other dating approaches and the widely established deglaciation history of the region, probably owing to cosmogenic inheritance and insufficient glacial erosion.
在此,我们首次介绍了挪威北部特罗姆斯岛北部和芬马克郡西部罗森达伦(Rotsunddalen)的大冰期(Lateglacial)和全新世(Holocene)冰川史,其依据是使用施密特锤(Schmidt hammer)进行的相对和数值冰碛测年、土壤年代测序和陆地宇宙成因核素测年。我们将这些年代学数据与冰川地貌区域图相结合,假设了从大约 14 ka 年至今的冰川历史中的关键事件。我们的重建结果表明,在横跨特罗姆斯和芬马克中部的主冰原消融之后,大约在 12.1 ka 到 10.6 ka 之间,山地冰川在靠近海岸的陆地上终止。芬诺斯坎迪亚主冰原边缘向东南方向的持续后退导致了几个大型高原冰原和出口冰川的分离,这些冰川在大约 10.2-9.2 ka(我们将其归于厄尔达伦事件)和 8.4-8.2 ka(与 8.2 ka 寒冷事件大致同时)产生了冰碛。尽管后者与斯堪的纳维亚芬斯事件(Scandinavian Finse Event)相吻合,但很少有冰碛被测定为这一时期,因此我们将其视为一个暂定假设,有待未来工作的检验。在全新世热极盛期(约 6.6 至 6.3 ka),该地区的大部分(如果不是全部)冰川消失,但在新冰期又重新生长,并产生了年代约为 4.7 ka 的大型冰碛,这些冰碛位于著名的小冰期冰碛(以前的年代为公元 1810 年代至 1870 年代)的几百米远处。鉴于我们测年方法的局限性,挪威北部保存的这一时期的冰碛也值得进一步研究。我们还强调,这些冰碛的陆地宇宙成因核素年代测定与其他年代测定方法以及该地区广泛确定的冰川消融历史并不一致,这可能是由于宇宙成因继承和冰川侵蚀不充分造成的。
{"title":"Reconstructing the Holocene glacial history of northern Troms and western Finnmark, Arctic Norway","authors":"Josh R. Leigh, Richard S. Jones, Chris R. Stokes, David J. A. Evans, J. Rachel Carr, Liss M. Andreassen","doi":"10.1111/bor.12668","DOIUrl":"10.1111/bor.12668","url":null,"abstract":"<p>Here we present the first Lateglacial and Holocene glacial history from Rotsunddalen, northern Troms and western Finnmark county, northern Norway, based on both relative and numerical moraine dating using Schmidt hammer, soil chronosequencing and terrestrial cosmogenic nuclide dating. We combine these chronological data with a regional map of the glacial geomorphology to hypothesize key events in the glacial history from around 14 ka to present. Our reconstruction shows that, following deglaciation of the main ice sheet across central Troms and Finnmark, mountain glaciers were terminating on land, close to the coast, between around 12.1 and 10.6 ka. Continued recession of the main Fennoscandian Ice Sheet margin towards the SE led to the isolation of several large plateau icefields and outlet glaciers that generated moraines at around 10.2–9.2 ka, which we ascribe to the Erdalen Event, and 8.4–8.2 ka, which is broadly contemporaneous with the 8.2 ka cold event. Although the latter corresponds with the Scandinavian Finse Event, very few moraines have been dated to this time and we therefore view it as a tentative hypothesis for future work to test. During the Holocene Thermal Maximum (~6.6 to 6.3 ka) most (if not all) glaciers in the region disappeared, but then regrew during the Neoglaciation and produced large moraines dated to around 4.7 ka that lie a few hundred metres distal to the prominent Little Ice Age moraines (previously dated to AD 1810s–1870s). Given the limitations of our dating approach, the preservation of moraines dated to this period in northern Norway also warrants further investigation. We also highlight that terrestrial cosmogenic nuclide dating of the moraines is not consistent with other dating approaches and the widely established deglaciation history of the region, probably owing to cosmogenic inheritance and insufficient glacial erosion.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 4","pages":"619-654"},"PeriodicalIF":2.4,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12668","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141353004","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}
Rebecca E. Lee, Rodrigo A. Narro Pérez, Carolyn H. Eyles
Glacial deposits are important sources of palaeoclimatic information but not all deposits are formed by processes that reflect the overall climatic conditions of a region; surge-type glaciers undergo periodic episodes of rapid ice movement, often unrelated to ambient climatic conditions. This study examines the glacier forefields of Öldufellsjökull and western Sléttjökull, two outlet glaciers of the Mýrdalsjökull Ice Cap in southern Iceland, to identify landform characteristics indicative of past episodes of fast flow. Previous studies suggest episodes of fast flow at these glaciers in the past century. Remotely sensed data and field investigations were combined to complete a landsystem analysis of the forefields of these glaciers and an uncrewed aerial vehicle was used to collect high-resolution imagery of areas of particular interest. Two assemblages of landsystems are identified on each forefield, which pass from streamlined landforms containing abundant flutes close to the glacier to spatially restricted bands of arcuate moraines with associated glaciofluvial and glaciolacustrine deposits more distally. This distribution of landsystem tracts has limited similarity to the current surge-type glacier landsystem model, suggesting that other processes are controlling the development of landform–sediment assemblages. Using a high-resolution digital elevation model of an area within the 1984 ice margin, two distinct landform types were identified that were not apparent on the coarse resolution imagery: hummocky moraine and a circular feature hypothesized to have formed as a result of water escape caused by changing hydrological regimes. The forefields of Öldufellsjökull and western Sléttjökull lack many of the characteristics typical of surge-type landsystems and instead are more similar to the active temperate landsystem common in Iceland.
{"title":"Landsystem analysis of temperate non-surging glaciers on the Mýrdalsjökull Ice Cap, southern Iceland","authors":"Rebecca E. Lee, Rodrigo A. Narro Pérez, Carolyn H. Eyles","doi":"10.1111/bor.12667","DOIUrl":"10.1111/bor.12667","url":null,"abstract":"<p>Glacial deposits are important sources of palaeoclimatic information but not all deposits are formed by processes that reflect the overall climatic conditions of a region; surge-type glaciers undergo periodic episodes of rapid ice movement, often unrelated to ambient climatic conditions. This study examines the glacier forefields of Öldufellsjökull and western Sléttjökull, two outlet glaciers of the Mýrdalsjökull Ice Cap in southern Iceland, to identify landform characteristics indicative of past episodes of fast flow. Previous studies suggest episodes of fast flow at these glaciers in the past century. Remotely sensed data and field investigations were combined to complete a landsystem analysis of the forefields of these glaciers and an uncrewed aerial vehicle was used to collect high-resolution imagery of areas of particular interest. Two assemblages of landsystems are identified on each forefield, which pass from streamlined landforms containing abundant flutes close to the glacier to spatially restricted bands of arcuate moraines with associated glaciofluvial and glaciolacustrine deposits more distally. This distribution of landsystem tracts has limited similarity to the current surge-type glacier landsystem model, suggesting that other processes are controlling the development of landform–sediment assemblages. Using a high-resolution digital elevation model of an area within the 1984 ice margin, two distinct landform types were identified that were not apparent on the coarse resolution imagery: hummocky moraine and a circular feature hypothesized to have formed as a result of water escape caused by changing hydrological regimes. The forefields of Öldufellsjökull and western Sléttjökull lack many of the characteristics typical of surge-type landsystems and instead are more similar to the active temperate landsystem common in Iceland.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 4","pages":"593-618"},"PeriodicalIF":2.4,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12667","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141353347","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}
Pub Date : 2024-06-10eCollection Date: 2024-01-01DOI: 10.14744/nci.2022.47124
Gulistan Huriye Bozdag Baskaya
Neck cysts can be classified as congenital, infectious-inflammatory, and neoplastic. Hydatid disease is a parasitic infection caused by Echinococcus, is usually seen in the liver and lung and, is rare in the head and neck region even in endemic areas. If not treated, a life-threatening condition may be encountered. In this study, a case of hydatid cyst operated due to a cystic lesion with a diameter of approximately 8 cm in the neck was presented by reviewing the literature.
{"title":"A rare pathology in the neck: Hydatid cyst.","authors":"Gulistan Huriye Bozdag Baskaya","doi":"10.14744/nci.2022.47124","DOIUrl":"10.14744/nci.2022.47124","url":null,"abstract":"<p><p>Neck cysts can be classified as congenital, infectious-inflammatory, and neoplastic. Hydatid disease is a parasitic infection caused by Echinococcus, is usually seen in the liver and lung and, is rare in the head and neck region even in endemic areas. If not treated, a life-threatening condition may be encountered. In this study, a case of hydatid cyst operated due to a cystic lesion with a diameter of approximately 8 cm in the neck was presented by reviewing the literature.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"50 1","pages":"258-260"},"PeriodicalIF":0.9,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11237831/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80441847","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}
This contribution summarizes the most informative loess–palaeosol sequences (LPS) and fluvial terrace records from the late Middle Pleistocene (LMP) of northern France demonstrating the reliability of the cyclostratigraphic approach for the interpretation of pedosedimentary sequences controlled by major glacial–interglacial climatic cycles. In this area, continental mollusc assemblages from interglacial fluvial silts and calcareous tufas are particularly rich and diverse and marker species define the malacological signatures of each interglacial optimum for Marine Isotope Stages (MIS) 11, 9 and 5e. This approach shows that the forest was less developed during MIS 7, suggesting that climatic conditions were either drier and/or cooler than during other Pleistocene interglacials. In the Somme basin, the terrace system shows that two alluvial formations were deposited between early MIS 8 and late MIS 7. In some LPS, the occurrence of two pedosedimentary sub-cycles (IIa and IIb), separated by a relatively long (~12 ka) and cold period, corresponding to an ‘aborted glacial’ (MIS 7d), underlines the complex pattern of this unusual ‘interglacial’. Overall, during the LMP, each soil complex corresponding to interglacial and early-glacial periods from MIS 11 to MIS 5 is broadly made up of the same soil facies but exhibits a specific succession pattern or signature. Throughout the area, LPS show a huge change in both the deposition rates and the geographical extent of typical calcareous loess at the beginning of MIS 6. This so-called ‘Loess Revolution’ probably reflects a change in the palaeogeography of the southern North Sea and eastern Channel source areas at times marked by the coalescence of the British and Scandinavian ice sheets. MIS 6 is also characterized by the oldest evidence of permafrost development in the area. In addition, this work allows the age of the Lower/Middle Palaeolithic boundary to be confirmed, with the oldest occurrence of Levallois technology being around 300 ka.
这篇论文总结了法国北部中更新世晚期(LMP)最翔实的黄土-古溶胶序列(LPS)和河流阶地记录,证明了循环地层学方法在解释受主要冰川-间冰期气候周期控制的沉积岩序列方面的可靠性。在这一地区,来自冰期河道淤泥和钙质泥灰岩的大陆软体动物组合特别丰富多样,标记物种确定了海洋同位素阶段(MIS)11、9 和 5e 的每个冰期最佳的哺乳动物特征。这种方法表明,森林在 MIS 7 期间不太发达,这表明当时的气候条件比其他更新世间冰期更干燥和/或更凉爽。在索姆河盆地,阶地系统显示,在 MIS 8 早期和 MIS 7 晚期之间有两个冲积层沉积。在一些 LPS 中,出现了两个沉积亚周期(IIa 和 IIb),中间相隔一个相对较长(约 12 ka)的寒冷时期,相当于一个 "中止的冰期"(MIS 7d),这突出了这个不寻常的 "间冰期 "的复杂模式。总体而言,在晚期冰期,从 MIS 11 到 MIS 5,与间冰期和早冰期相对应的每个土壤复合体大致由相同的土壤面层组成,但表现出特定的演替模式或特征。在整个地区,LPS 显示,在 MIS 6 开始时,典型钙质黄土的沉积速率和地理范围都发生了巨大变化。 这场所谓的 "黄土革命 "可能反映了北海南部和英吉利海峡东部源区古地理的变化,当时的标志是英国和斯堪的纳维亚冰盖的融合。MIS 6 也是该地区永冻土发展的最古老证据。此外,这项研究还证实了旧石器时代下/中叶边界的年龄,最古老的列瓦鲁瓦技术出现在大约 300 ka。
{"title":"Late Middle Pleistocene (MIS 10–6) glacial–interglacial records from loess–palaeosol and fluvial sequences from northern France: a cyclostratigraphic approach","authors":"Pierre Antoine, Nicole Limondin-Lozouet","doi":"10.1111/bor.12662","DOIUrl":"https://doi.org/10.1111/bor.12662","url":null,"abstract":"<p>This contribution summarizes the most informative loess–palaeosol sequences (LPS) and fluvial terrace records from the late Middle Pleistocene (LMP) of northern France demonstrating the reliability of the cyclostratigraphic approach for the interpretation of pedosedimentary sequences controlled by major glacial–interglacial climatic cycles. In this area, continental mollusc assemblages from interglacial fluvial silts and calcareous tufas are particularly rich and diverse and marker species define the malacological signatures of each interglacial optimum for Marine Isotope Stages (MIS) 11, 9 and 5e. This approach shows that the forest was less developed during MIS 7, suggesting that climatic conditions were either drier and/or cooler than during other Pleistocene interglacials. In the Somme basin, the terrace system shows that two alluvial formations were deposited between early MIS 8 and late MIS 7. In some LPS, the occurrence of two pedosedimentary sub-cycles (IIa and IIb), separated by a relatively long (~12 ka) and cold period, corresponding to an ‘aborted glacial’ (MIS 7d), underlines the complex pattern of this unusual ‘interglacial’. Overall, during the LMP, each soil complex corresponding to interglacial and early-glacial periods from MIS 11 to MIS 5 is broadly made up of the same soil facies but exhibits a specific succession pattern or signature. Throughout the area, LPS show a huge change in both the deposition rates and the geographical extent of typical calcareous loess at the beginning of MIS 6. This so-called ‘Loess Revolution’ probably reflects a change in the palaeogeography of the southern North Sea and eastern Channel source areas at times marked by the coalescence of the British and Scandinavian ice sheets. MIS 6 is also characterized by the oldest evidence of permafrost development in the area. In addition, this work allows the age of the Lower/Middle Palaeolithic boundary to be confirmed, with the oldest occurrence of Levallois technology being around 300 ka.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 4","pages":"476-503"},"PeriodicalIF":2.4,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12662","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525680","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}
Sofia E. Kjellman, Elizabeth K. Thomas, Wesley R. Farnsworth, Owen C. Cowling, Lis Allaart, Skafti Brynjólfsson, Anders Schomacker
Svalbard spans large climate gradients, associated with atmospheric circulation patterns and variations in ocean heat content and sea ice cover. Future precipitation increases are projected to peak in the northeast and to mainly occur in winter, but uncertainties underscore the need for reconstructions of long-term spatial and temporal variations in precipitation amounts and seasonality. We use lipid biomarkers from four sedimentary lake records along a climatic gradient from western to northeastern Svalbard to reconstruct Holocene water cycle changes. We measured the leaf wax hydrogen isotopic composition of long-chain (terrestrial) and mid-chain (aquatic) n-alkanoic acids, reflecting δ2H of precipitation (δ2Hprecip) and lake water (δ2Hlake), respectively. δ2Hprecip values mainly reflect summer precipitation δ2H and evapotranspiration, whereas δ2Hlake values can reflect various precipitation seasonality due to varying lake hydrology. For one lake, we used the difference between δ2Hprecip and δ2Hlake (εprecip-lake) to infer summer evapotranspiration changes. Relatively 2H-enriched δ2Hprecip values and higher εprecip-lake in the Early and Middle Holocene suggest warm summers with higher evapotranspiration, and/or more proximal summer moisture. After c. 6 cal. ka BP, 2H-depleted δ2Hprecip values and lower εprecip-lake indicate summer cooling, less evapotranspiration, or more distally derived moisture. Early to Middle Holocene decrease in δ2Hlake values in two northern Spitsbergen lakes reflects an increase in the proportion of winter relative to summer precipitation, associated with regional warming and increased moisture supply, which may be due to increased distal moisture supply and/or reduced sea ice cover. Our northern Svalbard δ2Hlake records suggest great Late Holocene climate variability with periodic winter precipitation increases or decreases in summer precipitation inflow to the lakes. We find that Holocene summer precipitation δ2H values mainly follow changes in summer insolation and temperature, whereas the seasonal distribution of precipitation is sensitive to catchment hydrology, regional ocean surface conditions, and moisture source changes.
斯瓦尔巴横跨巨大的气候梯度,这与大气环流模式以及海洋热含量和海冰覆盖率的变化有关。据预测,未来降水量的增加将在东北部达到峰值,并且主要发生在冬季,但不确定性突出表明需要重建降水量和季节性的长期时空变化。我们利用斯瓦尔巴群岛西部到东北部气候梯度上的四个沉积湖记录中的脂质生物标志物来重建全新世的水循环变化。我们测量了长链(陆生)和中链(水生)正烷酸的叶蜡氢同位素组成,分别反映了降水(δ2Hprecip)和湖水(δ2Hlake)的δ2H。δ2Hprecip值主要反映夏季降水δ2H和蒸发蒸腾作用,而δ2Hlake值则可反映因湖泊水文条件不同而导致的不同降水季节性。对于一个湖泊,我们利用 δ2Hprecip 与 δ2Hlake 之间的差值(εprecip-lake)来推断夏季蒸散量的变化。全新世早期和中期相对富集的 2H δ2Hprecip值和较高的εprecip-lake表明夏季温暖,蒸散量较大,和/或夏季水分较多。在约 6 cal. ka BP 之后,2H 贫化的 δ2Hprecip 值和较低的εprecip-lake 表明夏季变冷、蒸散量减少或远端水分增加。斯匹次卑尔根群岛北部两个湖泊全新世早期至中期δ2Hlake值的下降反映了冬季降水相对于夏季降水比例的增加,这与区域变暖和水分供应增加有关,可能是由于远端水分供应增加和/或海冰覆盖减少所致。我们的斯瓦尔巴群岛北部 δ2Hlake 记录表明,全新世晚期的气候变化很大,流入湖泊的冬季降水量周期性增加或夏季降水量周期性减少。我们发现,全新世夏季降水δ2H 值主要随夏季日照和气温的变化而变化,而降水的季节分布则对集水区水文、区域海洋表面条件和水汽源变化非常敏感。
{"title":"Seasonal precipitation variability on Svalbard inferred from Holocene sedimentary leaf wax δ2H","authors":"Sofia E. Kjellman, Elizabeth K. Thomas, Wesley R. Farnsworth, Owen C. Cowling, Lis Allaart, Skafti Brynjólfsson, Anders Schomacker","doi":"10.1111/bor.12661","DOIUrl":"https://doi.org/10.1111/bor.12661","url":null,"abstract":"<p>Svalbard spans large climate gradients, associated with atmospheric circulation patterns and variations in ocean heat content and sea ice cover. Future precipitation increases are projected to peak in the northeast and to mainly occur in winter, but uncertainties underscore the need for reconstructions of long-term spatial and temporal variations in precipitation amounts and seasonality. We use lipid biomarkers from four sedimentary lake records along a climatic gradient from western to northeastern Svalbard to reconstruct Holocene water cycle changes. We measured the leaf wax hydrogen isotopic composition of long-chain (terrestrial) and mid-chain (aquatic) <i>n</i>-alkanoic acids, reflecting δ<sup>2</sup>H of precipitation (δ<sup>2</sup>H<sub>precip</sub>) and lake water (δ<sup>2</sup>H<sub>lake</sub>), respectively. δ<sup>2</sup>H<sub>precip</sub> values mainly reflect summer precipitation δ<sup>2</sup>H and evapotranspiration, whereas δ<sup>2</sup>H<sub>lake</sub> values can reflect various precipitation seasonality due to varying lake hydrology. For one lake, we used the difference between δ<sup>2</sup>H<sub>precip</sub> and δ<sup>2</sup>H<sub>lake</sub> (ε<sub>precip-lake</sub>) to infer summer evapotranspiration changes. Relatively <sup>2</sup>H-enriched δ<sup>2</sup>H<sub>precip</sub> values and higher ε<sub>precip-lake</sub> in the Early and Middle Holocene suggest warm summers with higher evapotranspiration, and/or more proximal summer moisture. After <i>c</i>. 6 cal. ka BP, <sup>2</sup>H-depleted δ<sup>2</sup>H<sub>precip</sub> values and lower ε<sub>precip-lake</sub> indicate summer cooling, less evapotranspiration, or more distally derived moisture. Early to Middle Holocene decrease in δ<sup>2</sup>H<sub>lake</sub> values in two northern Spitsbergen lakes reflects an increase in the proportion of winter relative to summer precipitation, associated with regional warming and increased moisture supply, which may be due to increased distal moisture supply and/or reduced sea ice cover. Our northern Svalbard δ<sup>2</sup>H<sub>lake</sub> records suggest great Late Holocene climate variability with periodic winter precipitation increases or decreases in summer precipitation inflow to the lakes. We find that Holocene summer precipitation δ<sup>2</sup>H values mainly follow changes in summer insolation and temperature, whereas the seasonal distribution of precipitation is sensitive to catchment hydrology, regional ocean surface conditions, and moisture source changes.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 3","pages":"430-452"},"PeriodicalIF":2.4,"publicationDate":"2024-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12661","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141624592","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}
Ernst Johnson, Carl Regnéll, Peter D. Heintzman, Anna Linderholm
The postglacial recolonization of Fennoscandian flora and fauna was initiated when the land became accessible as the last ice sheet retreated. In northern Sweden, plants are represented in pollen and macrofossil records, but there is no genetic evidence from the first plants, animals or humans in the region, mainly owing to an absence of osteological finds. The questions of who the first postglacial peoples, or pioneers, were and where they came from therefore remain unanswered. Previous palaeogenomic analyses from remains from adjacent regions have suggested that two main routes into Sweden could have been taken by the pioneers, one from the SW through modern-day Denmark and Norway, and one from the east via Finland. However, no direct genetic evidence from the pioneers of northern Sweden exists. Modern technology has provided the ancient DNA field with an updated toolbox that could allow for novel approaches for revealing the origin and genetic profiles of the first Scandinavians, of which sedimentary ancient DNA (sedaDNA) is well placed. Lake sediments are now a routine source of sedaDNA that have been used to record environmental changes and detect species that lived in the surrounding lake catchment. This review will provide context and background, a summary of the ground-breaking studies within the field of lacustrine sedaDNA, and relevant methodology to address the scientific questions at hand. We conclude that the field is mature enough to provide insight into the origins and arrival times of the first postglacial humans that migrated into northern Sweden.
冰川期后,随着最后一块冰原的消退,这片土地变得可以进入,芬诺斯坎迪亚动植物群开始重新定居。在瑞典北部,植物在花粉和大型化石记录中都有体现,但没有该地区最早的植物、动物或人类的遗传证据,这主要是由于缺乏骨骼方面的发现。因此,关于谁是冰川期后的第一批人或先驱者以及他们来自哪里的问题仍然没有答案。以前对邻近地区遗骸进行的古基因组分析表明,先驱者进入瑞典可能有两条主要路线,一条是从西南部经过现代的丹麦和挪威,另一条是从东部经过芬兰。然而,瑞典北部的先民并没有直接的遗传证据。现代技术为古 DNA 领域提供了一个更新的工具箱,可以用新的方法揭示第一批斯堪的纳维亚人的起源和遗传特征,其中沉积古 DNA(sedaDNA)是一个很好的工具。目前,湖泊沉积物是沉积 DNA 的常规来源,已被用于记录环境变化和检测生活在周围湖泊集水区的物种。本综述将介绍相关背景,总结湖泊沉积 DNA 领域的突破性研究,以及解决当前科学问题的相关方法。我们的结论是,该领域已经足够成熟,可以让我们深入了解第一批迁徙到瑞典北部的冰川期后人类的起源和抵达时间。
{"title":"The potential of lacustrine sedimentary ancient DNA for revealing human postglacial recolonization patterns in northern Sweden – a review","authors":"Ernst Johnson, Carl Regnéll, Peter D. Heintzman, Anna Linderholm","doi":"10.1111/bor.12660","DOIUrl":"https://doi.org/10.1111/bor.12660","url":null,"abstract":"<p>The postglacial recolonization of Fennoscandian flora and fauna was initiated when the land became accessible as the last ice sheet retreated. In northern Sweden, plants are represented in pollen and macrofossil records, but there is no genetic evidence from the first plants, animals or humans in the region, mainly owing to an absence of osteological finds. The questions of who the first postglacial peoples, or pioneers, were and where they came from therefore remain unanswered. Previous palaeogenomic analyses from remains from adjacent regions have suggested that two main routes into Sweden could have been taken by the pioneers, one from the SW through modern-day Denmark and Norway, and one from the east via Finland. However, no direct genetic evidence from the pioneers of northern Sweden exists. Modern technology has provided the ancient DNA field with an updated toolbox that could allow for novel approaches for revealing the origin and genetic profiles of the first Scandinavians, of which sedimentary ancient DNA (sedaDNA) is well placed. Lake sediments are now a routine source of sedaDNA that have been used to record environmental changes and detect species that lived in the surrounding lake catchment. This review will provide context and background, a summary of the ground-breaking studies within the field of lacustrine sedaDNA, and relevant methodology to address the scientific questions at hand. We conclude that the field is mature enough to provide insight into the origins and arrival times of the first postglacial humans that migrated into northern Sweden.</p>","PeriodicalId":9184,"journal":{"name":"Boreas","volume":"53 3","pages":"347-359"},"PeriodicalIF":2.4,"publicationDate":"2024-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12660","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141624593","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}