| 1. |
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| 2. |
- Bennike, Ole, et al.
(författare)
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New interglacial deposits from Copenhagen, Denmark : marine Isotope Stage 7
- 2019
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Ingår i: Boreas. - : Wiley-Blackwell. - 0300-9483 .- 1502-3885. ; 48:1, s. 107-118
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Tidskriftsartikel (refereegranskat)abstract
- During a pre-site survey and construction of a new metro route and station in Copenhagen, fossiliferous organic-rich sediments were encountered. This paper reports on multidisciplinary investigations of these organic sediments, which occurred beneath a sediment succession with a lower till, glacifluvial sand and gravel, an upper till and glacifluvial sand. The organic sediments were underlain by glacifluvial sand and gravel. The organic-rich sediments, which were up to 0.5 m thick, accumulated in a low-energy environment, possibly an oxbow lake. They were rich in plant fossils, which included warmth-demanding trees and other species, such as Najas minor, indicating slightly higher summer temperatures than at present. Freshwater shells were also frequent. Bithynia opercula allowed the sediments to be put into an aminostratigraphical framework. The amino acid racemization (AAR) ratios indicate that the organic sediments formed during Marine Isotope Stage 7 (MIS 7), which is consistent with optically stimulated luminescence dating that gave ages of 206 and 248 ka from the underlying minerogenic deposit. The assemblages from Trianglen are similar to interglacial deposits from the former Free Port (1.4 km away) in Copenhagen, except that Corbicula and Pisidium clessini were not found at Trianglen. The presence of these bivalves at the Free Port and the ostracod Scottia tumida at Trianglen indicates a pre-Eemian age. AAR data from archived Bithynia opercula from the Free Port were almost identical to those from Trianglen, indicating that the two sites are contemporary. We suggest the Trianglen interglacial be used as a local name for the MIS 7 interglacial deposits in Copenhagen. MIS 7 deposits have rarely been documented from the region, but MIS 7 deposits may have been mistaken for other ages. The use of AAR ratios in Bithynia opercula has a great potential for correlation of interglacial non-marine deposits in mainland northern Europe.
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| 3. |
- Borzenkova, Irena, et al.
(författare)
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Climate Change During the Holocene (Past 12,000 Years)
- 2015
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Ingår i: Second Assessment of Climate Change for the Baltic Sea Basin. - Cham : Springer. - 9783319160054 - 9783319160061 ; , s. 25-49
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Bokkapitel (refereegranskat)abstract
- This chapter summarises the climatic and environmental information that can be inferred from proxy archives over the past 12,000 years. The proxy archives from continental and lake sediments include pollen, insect remnants and isotopic data. Over the Holocene, the Baltic Sea area underwent major changes due to two interrelated factors—melting of the Fennoscandian ice sheet (causing interplay between global sea-level rise due to the meltwater and regional isostatic rebound of the earth’s crust causing a drop in relative sea level ) and changes in the orbital configuration of the Earth (triggering the glacial to interglacial transition and affecting incoming solar radiation and so controlling the regional energy balance). The Holocene climate history showed three stages of natural climate oscillations in the Baltic Sea region: short-term cold episodes related to deglaciation during a stable positive temperature trend (11,000–8000 cal year BP); a warm and stable climate with air temperature 1.0–3.5 °C above modern levels (8000–4500 cal year BP), a decreasing temperature trend; and increased climatic instability (last 5000–4500 years). The climatic variation during the Lateglacial and Holocene is reflected in the changing lake levels and vegetation , and in the formation of a complex hydrographical network that set the stage for the Medieval Warm Period and the Little Ice Age of the past millennium.
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| 4. |
- Buckland, Philip I., 1973-, et al.
(författare)
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Explaining Late Quaternary beetle extinctions in the UK using palaeoenvironmental databases for quantitative environmental reconstruction
- 2015
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Konferensbidrag (refereegranskat)abstract
- The comparison of palaeoenvironmental and archaeological records of fossil insects with modern red data books can provide a picture of local extinctions. Buckland & Buckland (2012) performed such a study on the Coleoptera of the British Isles, using the BugsCEP database for the fossil data, and looking at broad chronological divisions. The ecology of these regionally extinct beetles, all of which are extant in other parts of the World, may be used to investigate the environmental and climatic changes which may have lead to their extirpation. This process can be semi-automated and habitats quantified through the use of ecological classification and a database infrastructure which links fossil and modern ecological and climate data (Buckland & Buckland 2006; http://www.bugscep.com). Preliminary results indicate that the majority of extirpated species with mid-Holocene records were dependent on woodland environments (Buckland 2014). These investigations can be refined by using narrower time-slices, interpolating dating evidence and including more comprehensive archaeological dating evidence. The expansion of the analysis to include the full assemblages found in the samples containing the extirpated species also allows for a more comprehensive picture of the long-term relationships between biodiversity, environmental and climatic change and human activity.
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| 5. |
- Cui, Qiao-Yu, et al.
(författare)
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A case study of the role of climate, humans, and ecological setting in Holocene fire history of northwestern Europe
- 2015
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Ingår i: Science China. Earth Sciences. - : Springer Science and Business Media LLC. - 1674-7313 .- 1869-1897. ; 58:2, s. 195-210
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Tidskriftsartikel (refereegranskat)abstract
- We present the major results from studies of fire history over the last 11000 years (Holocene) in southern Sweden, on the basis of palaeoecological analyses of peat sequences from three small peat bogs. The main objective is to emphasize the value of multiple, continuous sedimentary records of macroscopic charcoal (macro-C) for the reconstruction of local to regional past changes in fire regimes, the importance of multi-proxy studies, and the advantage of model-based estimates of plant cover from pollen data to assess the role of tree composition and human impact in fire history. The chronologies at the three study sites are based on a large number of C-14 dates from terrestrial plant remains and age-depth models are achieved using Bayesian statistics. Fire history is inferred from continuous records of macro-C and microscopic charcoal counts on pollen slides. The Landscape Reconstruction Algorithm (LRA) for pollen-based quantitative reconstruction of local vegetation cover is applied on the three pollen records for plant cover reconstruction over the entire Holocene. The results are as follows: (1) the long-term trends in fire regimes are similar between sites, i.e., frequent fires during the early Holocene until ca. 9 ka BP, low fire frequency during the mid-Holocene, and higher fire frequency from ca. 2.5 ka BP; (2) this broad trend agrees with the overall fire history of northwestern and western Europe north of the Mediterranean area, and is due to climate forcing in the early and mid-Holocene, and to anthropogenic land-use in the late Holocene; (3) the LRA estimates of plant cover at the three sites demonstrate that the relative abundance of pine played a primordial role in the early and mid-Holocene fire history; and (4) the between-site differences in the charcoal records and inferred fire history are due to local factors (i.e., relative abundance of pine, geomorphological setting, and anthropogenic land-use) and taphonomy of charcoal deposition in the small peat bogs. It is shown that continuous macro-C records are most useful to disentangle local from regional-subcontinental fire history, and climate-induced from human-induced fire regimes, and that pollen-based LRA estimates of local plant cover are more adequate than pollen percentages for the assessment of the role of plant composition on fire history.
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| 6. |
- Gaillard, Marie-José, et al.
(författare)
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The potential of pollen-based quantitative vegetation reconstructions in studies of past human settlements and use of resources – examples from Europe
- 2015
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Ingår i: Geophysical Research Abstracts.
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Konferensbidrag (refereegranskat)abstract
- There is a long tradition of collaboration between palaeoecologists and archaeologists in many parts of the world with the purpose of reconstructing the environment of humans through time and the study of the interactions between humans and their environment. Vegetation (i.e. vegetated landscapes and plants) has long been one of the most important parts of the environment for humans’ resources. Thanks to the interpretation of palaeoecological data such as pollen and plant macrofossils, it is well known that humans have used plants for their subsistence and formed many landscapes of the Earth through their activities over many millennia. Pollen analysis in particular has been used to reconstruct the landscapes of humans in order i) to learn something on their use of the landscape for building material, grazing and food (e.g. woods, grazed land, cultivated fields), and ii) to understand their influence on the landscape through deforestation in particular. Pollen data as proxy records of vegetation have been very useful to provide qualitative descriptions of cultural landscapes through time in terms of the presence of major tree, shrub and herb species, and the character of the landscape, wooded, “half-wooded” (or partly wooded), and primarily open (poorly wooded) (1). Efforts to calibrate pollen onto land-use in the 1990ies has made possible to provide more precise and detailed interpretation of pollen records in terms of land-use type (2). However, when it came to questions related to the size of cultivated land or grazed land in relation to wooded land, interpretation of pollen records has been problematic until recently. The non-linear relationship between pollen and vegetation due to inter-taxonomic differences in pollen productivity and pollen dispersion and deposition characteristics of plant taxa has long hampered estimation of the percentage cover of plant taxa or landscape units in the past. Thanks torecent developments in pollen-vegetation modelling, a new approach - the Landscape Reconstruction Algorithm (LRA) (3, 4) - makes it possible to estimate the cover of plant taxa or landscape units at both regional and local spatial scales using pollen records. The LRA has been tested and applied in various types of studies in Europe in particular. Examples from Europe and Scandinavia show that pollen-based quantitative reconstructions of vegetation cover, in combination with other palaeoecological records such as insect and plant macroremains, show the great potential of such studies to provide new insights on the use of landscapes and vegetation by humans in the past and its environmental consequences at both regional and local spatial scales (5, 6). These results provide a new environmental framework for the discussion and testing of hypotheses based on archaeological data.
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| 7. |
- Houmark-Nielsen, Michael, et al.
(författare)
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Evidence of ameliorated Middle Weichselian climate and sub-arctic environment in the western Baltic region : coring lake sediments at Klintholm, MOn, Denmark
- 2016
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Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 45:2, s. 347-359
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Tidskriftsartikel (refereegranskat)abstract
- Coring through glaciotectonically stacked Quaternary sediments situated below sea level on the island of MOn, Denmark, recovered a succession of interstadial sediments of Middle Weichselian age. Plant and animal remains including insects found in laminated sand and mud indicate deposition in a lake surrounded by dwarf shrubs, herbs, mosses and rare trees. The insect fauna indicates a mean July temperature of 8-12 degrees C, suggesting an arctic to sub-arctic environment, while winter temperatures around -8 to -22 degrees C suggest periglacial conditions with permafrost. Luminescence dating of sediment samples gave ages from 48-29ka, and radiocarbon dating indicates deposition of plant fragments between 45 and 36ka BP. The fossil assemblage from MOn shows close resemblance to those from other sites with similar ages found in the vicinity of the western Baltic Basin.
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| 8. |
- Möller, Per, et al.
(författare)
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Data set on sedimentology, palaeoecology and chronology of Middle to Late Pleistocene deposits on the Taimyr Peninsula, Arctic Russia
- 2019
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Ingår i: Data in Brief. - : Elsevier. - 2352-3409. ; 25, s. 1-35
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Tidskriftsartikel (refereegranskat)abstract
- This Data in Brief paper contains data (including images) from Quaternary sedimentary successions investigated along the Bol'shaya Balakhnya River and the Luktakh-Upper Taimyra-Logata river system on southern Taimyr Peninsula, NW Siberia (Russia). Marine foraminifera and mollusc fauna composition, extracted from sediment samples, is presented. The chronology (time of deposition) of the sediment successions is reconstructed from three dating methods; (i) radiocarbon dating of organic detritus (from lacustrine/fluvial sediment) and molluscs (marine sediment) as finite ages (usually <42 000 years) or as non-finite ages (>42 000-48 000 years) on samples/sediments beyond the radiocarbon dating limit; (ii) Electron Spin Resonance (ESR) dating on marine molluscs (up to ages >400 000 years); (iii) Optically Stimulated Luminescence (OSL) dating, usually effective up to 100-150 0000 years. Terrestrial Cosmogenic Nuclide (TCN) exposure dating has been applied to boulders resting on top of moraine ridges (Ice Marginal Zones). See (Moller et al., 2019) (doi.org/10.1016/j.earscirev.2019.04.004) for interpretation and discussion of all data. (c) 2019 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 9. |
- Möller, Per, et al.
(författare)
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Glacial history and palaeo-environmental change of southern Taimyr Peninsula, Arctic Russia, during the Middle and Late Pleistocene
- 2019
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Ingår i: Earth-Science Reviews. - : Elsevier. - 0012-8252 .- 1872-6828. ; 196
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Forskningsöversikt (refereegranskat)abstract
- We here reconstruct a glacial and climate history of arctic NW Siberia for the last similar to 600,000 years, based on the stratigraphy and chronology of 35 studied river sections on the southern Taimyr Peninsula. From this strati graphic mosaic we have identified four glacial events, marked by tills/glaciotectonics, which are intercalated with mainly marine sediments deposited in proglacial settings during transitions from glacial conditions into subsequent interglacials/interstadials. The traces of early shelf-based Kara Sea Ice Sheet (KSIS) glaciations in marine isotope stages (MIS) 12-14 and 8 are sparsely preserved, but these ice advances are suggested to have terminated far south into the central Siberian uplands, as also was the case with the younger Taz glaciation (MIS 6). The inception phase of the latter glaciation was complex, with ice advancing into a proglacial marine basin both from the south (Putorana - Anabar uplands) and the north. The deglaciation leading into the Karginsky interglacial (MIS 5e) was marked by the development of the southerrunost ice-marginal zones (IMZs) on the Taimyr lowlands - the Urdakh and Sampesa IMZs. The most recent (late Pleistocene) glacial cycle is recorded by three successively smaller KSIS advances from the Kara Sea shelf onto Taimyr, of which only the first, during Early Zyryanka (MIS 5d), reached south of the Byrranga Mountains, with its maximum extent marked by the Jangoda - Syntabul - Severokokorsky IMZ. Retreat of the ice margin during MIS 5c-b was accompanied by deposition of glaciomarine sediment in the proglacial basin and deposition of large successions of delta sediments in the foothills of the Byrranga Motmtains, reaching a >= 100 m above present sea level. The region north of the Byrranga Mountains was subjected to two subsequent KSIS glaciations, during MIS 4 and MIS 2, while the area south of the Byrranga Mountains transitioned to a terrestrial environment from the Middle into the Lower Zyryanka, as evidenced by deposition of fluvial, aeolian and ice-complex (Yedoma) sediments.
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