| 1. |
- Alexanderson, Helena, et al.
(författare)
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A sedimentary model for transverse inland dunes in central Scandinavia
- 2018
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Konferensbidrag (refereegranskat)abstract
- The largest dune fields in Sweden and Norway are small in international comparison but still form distinct parts of this previously glaciated landscape. The dunes formed c.10.5-9 ka ago, shortly after the last deglaciation, when winds close to the ice sheet were strong and vegetation was largely absent [1-4]. Since then they have been more or less stable and today they are covered by forest. Most of the dunes are curvi-linear in shape and formed transverse to the wind [5]. Here we present a sedimentary model for these transverse inland dunes, based on geophysical and sedimentological investigations of dunes at Skattungheden, Bonäsheden and Starmoen in central Sweden and south-eastern Norway. Ground-penetrating radar profiles reveal the main architectural elements of the dunes, while logging of sediment exposures in the dunes provide information on sedimentary structures. Grain-size analysis and scanning electron microscope studies of individual grains give us more detail on sediment characteristics.The main dune body, consisting of cross beds generally dipping 25-30°, makes up the largest part of the dunes; minor elements include windward side cover, dune-crest superimposed features and dune-toe apron (Fig. 1). The dominating sediment structures are planar parallel lamination, massive to vaguely stratified beds and a few types of secondary structures, such as bioturbation or physical disturbances. Few large erosional discordances are seen, and the dominating depositional processes are wind-ripple migration and some grain fall on the sloping lee sides. The sediments are well-sorted fine-to-medium sand, dominated by quartz, but with significant amounts of feldspar as well as some lithic fragments, micas and heavy minerals. Most grains are angular to subrounded and their surfaces display few traces of aeolian transport. Overall, the dune sands show large similarities to their source material (glacifluvial deposits), which suggests only short transport and brief reworking by aeolian processes.References[1] Alexanderson, H. and M. Bernhardson, OSL dating and luminescence characteristics of aeolian deposits and their source material in Dalarna, central Sweden Boreas, 2016. 45: p. 876-893.[2] Alexanderson, H. and M. Henriksen, A short-lived aeolian event during the Early Holocene in southeastern Norway. Quaternary Geochronology, 2015. 30: p. 175-180.[3] Bernhardson, M. and H. Alexanderson, Early Holocene NW-W winds reconstructed from small dune fields, central Sweden. Boreas, 2018.[4] Alexanderson, H. and D. Fabel, Holocene chronology of the Brattforsheden delta and inland dune field, SW Sweden. Geochronometria, 2015. 42: p. 1-16.[5] Bernhardson, M. and H. Alexanderson, Early Holocene dune field development in Dalarna, central Sweden: A geomorphological and geophysical case study. Earth Surface Processes and Landforms, 2017. 42: p. 1847-1859.
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| 2. |
- Alexanderson, Helena, et al.
(författare)
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Aeolian activity in Sweden: an unexplored environmental archive
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- During the course of this three-year project, we have studied aeolian deposits at 70 sites within sixteen areas in south-central Sweden. Inland dunes have been the focus, but some sites with coversand and coastal dunes have also been investigated. We have mapped dune morphology, mainly by LiDAR-based remote sensing, studied the internal sediment architecture by ground-penetrating radar profiling and in sediment exposures, documented the sedimentology of the deposits with field and laboratory methods as well as determined the age of the deposits with luminescence and radiocarbon dating. In this scientific report to the Geological Survey of Sweden, who funded the project, we present a summary of the project and its results. The largest and best developed dune fields are found at glacifluvial deposits in Värmland and Dalarna, while in areas south thereof there are mainly scattered dunes or coversand deposits. A range of dune types has been observed, but transverse dunes seem to be dominating and the majority of these are oriented roughly NE-SW. The bulk of the aeolian deposits were formed shortly after the local deglaciation and, once stabilised, do not appear to have been significantly reworked during the Holocene. Most Mid- and Late-Holocene aeolian deposits consist of coversand, apart from in coastal areas where e.g. young foredunes are found.Our results thus largely confirm the hypothesis of previous investigators but we do add a significant amount of new information. We provide, for the first time for most of our study areas, numerical ages for the aeolian deposits and thus provide the timing and duration of sand-drift events in south-central Sweden. The ages, in combination with detailed geomorphological mapping, allow us to distinguish phases of dune-field development, which are likely due to changes in wind patterns and vegetation cover, and also to correlate Swedish aeolian deposits to regional storminess periods. Based on sedimentological information we are able to reconstruct dominating depositional processes, transport paths and sediment sources. Additional outcomes of the project are e.g. methodological developments (LiDAR mapping, luminescence dating) and pilot studies of potential relevance for applied geology (coastal development).
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| 3. |
- Kalinska-Nartisa, Edyta, et al.
(författare)
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Age and sedimentary record of inland eolian sediments in Lithuania, NE European Sand Belt
- 2015
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Ingår i: Quaternary Research. - : Cambridge University Press (CUP). - 0033-5894 .- 1096-0287. ; 84:1, s. 82-95
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Tidskriftsartikel (refereegranskat)abstract
- We present a study based on four inland eolian locations in Eastern, Central and Southeastern Lithuania belonging to the northeastern part of the 'European Sand Belt' (ESB). Although there have been several previous studies of the ESB, this north-eastern extension has not been investigated before in any detail. The sedimentary structural-textural features are investigated and a chronology was derived using optically stimulated luminescence on both quartz and feldspar. The sedimentary structures and the rounding and surface characteristics of the quartz grains argue for a predominance of eolian transport. Additionally, some structural alternations and a significant contribution of non-eolian grains are interpreted as inherited local glacial/glaciofluvial-bearing lithologies. Three main (glaciolacustrine-) eolian phases are distinguished based on the position in the landscape and the luminescence ages: (1) An older eolian series around 15 to 16 ka, possibly correlated with the cold GS-2a event according to the GRIP stratigraphy, and (2) a younger eolian series around 14.0 ka, possibly representing the GI-Id and 1c events. The older eolian series is underlain by (3) a glaciolacustrine-eolian series for which the period of deposition remains uncertain due to the significant discrepancy between the ages based on quartz and feldspar. (C) 2015 University of Washington. Published by Elsevier Inc. All rights reserved.
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| 4. |
- Kalinska-Nartisa, Edyta, et al.
(författare)
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Luminescence dating of aeolian–coastal events on the Kristianstad plain, SE Sweden
- 2017
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Ingår i: Holocene. - : SAGE Publications. - 0959-6836. ; 27:1, s. 85-97
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Tidskriftsartikel (refereegranskat)abstract
- Aeolian–coastal sediments and landforms are excellent palaeoenvironmental archives, but chronological studies of coastal records are scarce in Sweden. In this study, we provide luminescence and radiocarbon ages of aeolian activity and coastal landscape evolution on the Kristianstad plain, SE Sweden, based on the investigations of two foredunes and two inland dunes at Åhus and Vittskövle. Additionally, we do a laboratory intercomparison of five young luminescence samples. The comparison shows a significant age difference most likely due to an instrumental difference. The equivalent dose cannot be determined accurately with the low irradiation times, and therefore, the results obtained from the reader with a lower dose rate are favoured and are largely supported by historical records. The oldest age, 11.6 ka, is from littoral sediments underlying an aeolian dune at Vittskövle and represents deposition in the Baltic Ice Lake. These deposits are topped by an organic horizon, which developed between AD 1476 and 1637, a time that partially corresponds with a short and abrupt climate warming in the ‘Little Ice Age’. The aeolian deposits are all younger. Sand mobilisation in the inland dunes took place around AD 1686–1799, related to forest destruction during war, intense cultivation of land or/and the coldest phase of the ‘Little Ice Age’. The foredunes are younger and were deposited at the beginning and in the end of the 20th century by easterly winds.
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| 5. |
- Kalińska-Nartiša, Edyta, et al.
(författare)
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Microtextural Inheritance on Quartz Sand Grains from Pleistocene Periglacial Environments of the Mazovian Lowland, Central Poland
- 2017
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Ingår i: Permafrost and Periglacial Processes. - : Wiley. - 1045-6740. ; 28:4, s. 741-756
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Tidskriftsartikel (refereegranskat)abstract
- Sand grains from Quaternary glacial, aeolian and fluvial deposits in the Mazovian Lowland, central Poland, were examined to characterize the effects of different Quaternary processes on sand-grain surfaces that experienced repeated cycles of intense polar-desert-like conditions during the Middle and Late Pleistocene. A cold, dry and windy periglacial environment prevailed here at least twice between the Saalian (Marine Isotope Stage (MIS) 6) and Holocene (MIS 1) stages. Because the surface characteristics of quartz sand grains can provide important palaeoenvironmental information, we examined grains extracted from sediment samples in different landforms to determine their surficial features from scanning electron microscope images. The grain surfaces were dominated by microtextures characteristic of aeolian-induced grain transformation, indicated by a high percentage of well-rounded, low-relief-worn grains with dish-shaped depressions, bulbous edges and upturned plates. Although remnants of previous sedimentary cycles were occasionally observed, aeolian effects were dominant even in glacial and fluvial settings. Quartz microtextures indicated that none of the examined grains represented their original setting, but rather suggested remobilisation under periglacial conditions.
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| 6. |
- Kalinska-Nartisa, Edyta, et al.
(författare)
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Sandy fan-like forms in the central-eastern mazovian lowland (central poland) : Textural record and chronology
- 2016
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Ingår i: Geografiska Annaler, Series A: Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 98:2, s. 111-127
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Tidskriftsartikel (refereegranskat)abstract
- A unique, continuous, fan-shaped belt of sandy landforms in the central-eastern Mazovian Lowland, Central Poland has been investigated using a multiproxy dataset of sediment physical properties and chronological framework. Although there are several previous studies of similar fan-like forms elsewhere in Central Poland, this central-eastern part has not been investigated in detail. A combined methodological approach, using grain-size distributions, the roundness, surface character and microtexture of quartz grains, and the mineral composition of the light and heavy fractions, indicate a predominantly aeolian origin for the fan-like forms. Overlying them are dunes, the sediment within which is derived mainly from the fan-like forms. Two main aeolian phases are distinguished based on luminescence ages: (1) between around 15 and 16 ka, possibly correlated with the Pomeranian Phase of the last (Vistulian) glaciation in Poland, and representing a phase with a poorly recorded deflation event; and (2) around 12 ka, associated with the Younger Dryas onset, when fresh, non-aeolian material was delivered to the system. Overall, the palaeoenvironmental pattern of the fan-like forms is controlled by the Upper Pleistocene aeolian trends.
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| 7. |
- Kalinska-Nartisa, Edyta, et al.
(författare)
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The fan-like forms in the southern margin of the Mazovian Lowland area (Central Poland) : a new high-resolution textural-timing study
- 2016
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Ingår i: International Journal of Earth Sciences. - : Springer Science and Business Media LLC. - 1437-3254 .- 1437-3262. ; 105:3, s. 885-903
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Tidskriftsartikel (refereegranskat)abstract
- An optically stimulated luminescence technique with a high-resolution sampling strategy, as well as a set of multiple proxies such as grain size distribution, shape, surface and microstructures of quartz grains, along with mineral composition of light and heavy fractions was used to investigate the age and origin of fan-like forms at the southern margin of Mazovian Lowland, Poland. The predominance of aeolian factors was observed throughout all of the investigated sites. However, the sedimentary variability of the grains reflected the superposed influence of multiple cold environmental factors such as snow/ice interbedded layers, cryoturbation processes or a “fluvial” transformation. Luminescence ages provide the first detailed chronology of the southern margin of the Mazovian Lowland. Deposition began after ca. 42 ka and onwards, and resulted in the depositional alternation of dry and humid environmental interactions. Between ca. 31 and 25 ka, the pre-LGM aeolian transformation took place. Finally, during the Pomeranian Phase in Poland at ~14 ka, polar desert environmental conditions prevailed.
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| 8. |
- Kalinska-Nartisa, Edyta, et al.
(författare)
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The north-eastern aeolian 'European Sand Belt' as potential record of environmental changes : A case study from Eastern Latvia and Southern Estonia
- 2016
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Ingår i: Aeolian Research. - : Elsevier BV. - 1875-9637. ; 22, s. 59-72
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Tidskriftsartikel (refereegranskat)abstract
- The Latvian and Estonian inland dunes belong to the north-eastern part of the 'European Sand Belt' (ESB). These dunes are widely distributed over broad glaciolacustrine plains and Late Glacial alluvial deltas, considered to be potential sources for the aeolian material. Little is known about these aeolian sediments and their substratum; here we present a detailed sedimentary structural and textural characterisation together with a luminescence-based chronology. Through a comparison between grain-size, rounding of quartz grains and surface characteristics in medium/coarse (0.5-0.8 mm) sand, and the light mineral content, we found an alternation of aeolian and periglacial components. Further, short-lasting aeolian abrasion and/or transportation periods, and a significant contribution of a nearby sediment source are suggested. Luminescence dating points to aeolian sand accumulation and dune formation between ~16 ka and ~9 ka. However, we also observed some presumably watertable controlled environmental conditions at ~13 ka; this corresponds with the occurrence of an ice-dammed/proglacial lake.
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| 9. |
- Kalinska-Nartisa, Edyta, et al.
(författare)
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Upper Pleistocene palaeoenvironmental changes at the Zwierzyniec site, Central Poland
- 2016
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Ingår i: Geological Quarterly. - : Polish Geological Institute - National Research Institute (PGI-NRI). - 1641-7291. ; 60:3, s. 610-623
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents the data on an Eemian-Late Glacial sedimentary sequence from the Zwierzyniec site, central Poland. A number of boreholes document one or two organic layers that occur beneath one or two horizons of clayey and silty deposits of ice-dammed lakes. This study demonstrates to which extent the Zwierzyniec site can contribute to a better understanding of the palaeoenvironmental changes during the Eemian-Vistulian time-frame in central Poland. To study it, a multi-proxy approach was applied, involving: palynological and plant macrofossil analysis, study of rounding of quartz grains and morphology of their surface, and investigations of sand mineralogy and till petrography. The results show that a till bed is overlain by a sandy series corresponding to the glacial-interglacial transition. Either one or two distinct peaks of organic accumulation are evidenced by peat horizons. The lower horizon records spectra with hazel and hornbeam, and did, therefore, accumulate in the Eemian. Observed only in some boreholes, the upper peat horizon marks the Brørup (or the lower part of the Rederstall stadial) represented by forest-steppe conditions with patchy mosaics of larch and further transition into sedges and herbaceous taxa. Localized in between the two peat sequences, the sandy horizon marks a long-lasting aeolian transformation with weathering by frost in the Early Vistulian. Again, significant changes of the palaeoenvironmental regime occurred, and are manifested in the one or two horizons of the glaciolacustrine sediments. This corresponded to the last glaciation in the region, when the ice-dammed lakes formed during the Main Stadial.
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| 10. |
- Lamsters, Kristaps, et al.
(författare)
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New luminescence ages reveal early to Middle Weichselian deposits in central Latvia
- 2017
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Ingår i: Geological Quarterly. - : Polish Geological Institute - National Research Institute (PGI-NRI). - 1641-7291. ; 61:2, s. 480-490
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Tidskriftsartikel (refereegranskat)abstract
- New optically stimulated luminescence (OSL) ages show that sandy deposits overlain by Late Weichselian subglacial till in central Latvia are of Early to Middle Weichselian age. The finer chronological resolution of unconsolidated sediment deposition in the Central Latvian Lowland (CLL) remains relatively unstudied, and here we provide a first characterisation of the deposits with respect to their age. Three OSL ages ranging between 84 ± 9 ka and 112 ± 11 ka suggest that the deposits studied in the CLL are of Early Weichselian age (MIS 5). We found no Middle Weichselian deposits in the CLL, and assume that any such younger sediments might have been eroded during the advance of the Zemgale Lobe in the Late Weichselian. One site, in the ice-marginal zone adjacent to the interlobate area, has nevertheless deposits dated to 44 ± 10 ka corresponding to the Middle Weichselian (MIS 3). Our results are compatible with existing ESR ages on three sets of Portlandia arctica shells from the central part of the lowland; the shells had been incorporated into glacial deposits during later glacial advances. Finally, our findings largely support ice-free conditions during the Early and Middle Weichselian in the middle and southern part of central Latvia.
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