Change search
Refine search result
1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Massuanganhe, Elidio A.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Universidade Eduardo Mondlane, Moçambique.
    Berntsson, Annika
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Westerberg, Lars-Ove
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Christiansson, Marie
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Achimo, Mussa
    Palaeogeography and dynamics of the deltaic wetland of Save River, Mozambique2018In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 489, p. 64-73Article in journal (Refereed)
    Abstract [en]

    Many mangrove wetland systems in deltaic environments are negatively affected by massive sedimentation fromriver inflows. In this paper we use the example of the Save River delta to assess the palaeogeographic distributionof mangrove wetlands and to analyze their dynamics. To track past occurrences of mangrove wetlands in thestudy area we have integrated sedimentological data with siliceous microfossil analysis combined with AMSradiocarbon and OSL dating. The results show a fine-grained deposit with an approximate thickness of 2 m,present at different sampling sites. In the upper deltaic plain, the deposit is interbedded between sand layers,while in the lower deltaic plain the deposit occupies the uppermost stratigraphic position. In most of thesampling sites the deposit shows a succession with brackish-marine diatoms at the bottom of the sequence whilethe upper part shows only scattered occurrences. Based on sedimentological and microfossil characteristics wehave interpreted the layer to represent a mangrove wetland deposit. The development of the deposit in the studyarea is suggested to have been initiated around 3100 cal. yr BP, induced by sea-level rise. Thereafter, the developmentfollowed the combined effect of a sea-level fall and delta progradation processes. In some areas,particularly in the proximal part of the delta, the mangrove deposit has developed progressively on top of thedelta-front. From around 1300 years ago (OSL) onwards, massive alluvial sedimentation impacted the mangroveecosystem. However, the retreat of mangrove wetland coincided with a regional fall of sea level. At the edges ofthe alluvial deposit, the current mangrove ecosystem has reclaimed the habitat in some sectors where gullyerosion has exposed the once extinct mangrove habitat.

  • 2.
    Massuanganhe, Elidio
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Universidade Eduardo Mondlane, Moçambique.
    Westerberg, Lars-Ove
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Achimo, Mussa
    Geomorphology and landscape evolution of Save River delta, South-central MozambiqueManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    The Save River delta has well-preserved geomorphological and sedimentological features with potential to reveal its evolution as well as past regional environmental changes, which are anticipated to integrate into other data at a global scale. In this study we mapped and integrated these features to understand the environmental processes that drove the late evolution of the delta. The results suggest that the present configuration of the delta was primarily dominated by a delta-front protruding into the sea, in a faulted coast section that may have favoured the formation of the depocenter. The development of the delta-front was initiated prior to c. 3100 cal. yrs BP, and around this age, fine-grained sediments started to accumulate on it forming a mangrove wetland deposit that expanded from the proximal sector of the delta to the current position shown in a geomorphological map. The results show successive dune ridges in the southern sector of the delta which indicate a series of consecutive shorelines over time as the delta prograded towards the current position. These dunes have created favourable conditions for accumulation of fine-grained sediments in the back-barrier sectors, contributing to the development of the mangrove wetland. An alluvial floodplain developed during the last millennium, probably a result of high precipitation the catchment area.

  • 3. Muru, Merle
    et al.
    Rosentau, Alar
    Preusser, Frank
    Plado, Juri
    Sibul, Ivo
    Joeleht, Argo
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Aunap, Raivo
    Kriiska, Aivar
    Reconstructing Holocene shore displacement and Stone Age palaeogeography from a foredune sequence on Ruhnu Island, Gulf of Riga, Baltic Sea2018In: Geomorphology, ISSN 0169-555X, E-ISSN 1872-695X, Vol. 303, p. 434-445Article in journal (Refereed)
    Abstract [en]

    Holocene shore displacement and the palaeogeography of Late Mesolithic and Late Neolithic settlements on Ruhnu Island, Gulf of Riga, were reconstructed using foredune sequence luminescence dating, sedimentological data supported by ground-penetrating radar analysis, and GIS-based landscape modelling. The foredune ridges consist of very well to well sorted fine-to medium-grained aeolian sand and are underlain by seaward dipping foreshore sediments. The studied sequence of 38 ridges was formed between 6.91 +/- 0.58 ka and 2.54 +/- 0.19 ka ago, and represents a period of falling relative sea level. Foredune plain progradation, with average rates of 0.3-0.6 m per year, was controlled by isostatic land uplift, which caused a continuous withdrawal of shorelines to lower elevations. The dated foredune succession was used to reconstruct the coastal palaeogeography of the island. Palaeogeographical reconstructions show that during two phases of Late Mesolithic habitation, at ca. 7.2 cal. ka BP and 6.2 cal. ka BP, seal hunters settled the coastal zone of Ruhnu Island. Based on tool material and pottery type they could have originated from Saaremaa Island, which according to palaeoreconstruction of the Gulf of Riga, was located approximately 70 km northwest of Ruhnu Island during the Late Mesolithic. Later signs of human occupation, radiocarbon dated to ca. 4.7 cal. ka BP, were from the centre of the island, hundreds of metres away from the shore at about 8 m above its contemporary sea level. This Late Neolithic habitation shows a clearly different pattern than earlier coastal settlement, and suggests a shift in subsistence strategy towards agriculture and animal husbandry.

  • 4.
    Norström, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences. Navarino Environmental Observatory, Greece.
    Katrantsiotis, Christos
    Stockholm University, Faculty of Science, Department of Physical Geography. Navarino Environmental Observatory, Greece.
    Finné, Martin
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography. Navarino Environmental Observatory, Greece.
    Smittenberg, Rienk H.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Biomarker hydrogen isotope composition (D) as proxy for Holocene hydroclimatic change and seismic activity in SW Peloponnese, Greece2018In: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417, Vol. 33, no 5, p. 563-574Article in journal (Refereed)
    Abstract [en]

    We present a 6000-year-long record tracing hydroclimate changes in SW Greece, based on hydrogen isotope composition of aquatic plant-derived n-C-23 alkanes (D-C23) in a sediment core from the Messenian plain, Peloponnese. The D-C23 record co-varies with other eastern Mediterranean records, suggesting relatively wetter conditions c. 6-4.5ka, followed by progressively drier conditions leading up to maximum aridity c. 2.8 ka. This arid phase was interrupted by a shift in D-C23 between 3.3 and 3.1ka inferring wetter conditions and/or tentative responses to anthropogenic water regulating activities during the Late Bronze Age. After 2.7ka, a return to more humid conditions was followed by increased dryness and stronger seasonality contrasts from c. 2.0ka. The D-C23 record shows three short-lived excursions (5.7, 5.3, 2.8ka), where isotope values dropped by >20 parts per thousand and immediately stabilized again. The events were paralleled by abrupt increases in sedimentation rates. We hypothesize that the isotopic shifts represent a response to mixing of ground water systems during tectonic events, followed by sealing of seismically derived cracks in the active fault. The outcome of the study is promising for future expansion of isotope-based proxies on sediments in the region, to reconstruct both hydroclimate and past seismic activity.

  • 5. Vilumaa, Kadri
    et al.
    Tonisson, Hannes
    Sugita, Shinya
    Buynevich, Ilya V.
    Kont, Are
    Muru, Merle
    Preusser, Frank
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Vaasma, Tiit
    Vandel, Egert
    Molodkov, Anatoly
    Järvelill, Johanna I.
    Past extreme events recorded in the internal architecture of coastal formations in the Baltic Sea Region2016In: Journal of Coastal Research, ISSN 0749-0208, E-ISSN 1551-5036, no SI 75, p. 775-779Article in journal (Refereed)
    Abstract [en]

    The postglacial uplift and transgressive-regressive phases of the Baltic Sea have affected the formation and displacement of sandy accumulation forms in the region. The dune-ridge complexes preserve a geological record of past sea-level fluctuations, coastal evolution, and extreme events, and offer insights into major driving mechanisms. This study aims to improve methodologies for identifying different storm signatures in coastal deposits using examples from Estonia and Latvia. The paleo-beach ridges are typically covered by aeolian sand, and the inter-ridge swales are mostly filled with organic sediments. Ground-penetrating radar surveys corroborate distinct textural patterns in sand layers underneath the ridges and swales. In the ridges, sharp seaward-dipping reflections represent storm scarps. The ridge sequences without dipping reflections suggest either aeolian origin or longshore transport; smaller sandy ridges, which are buried under peat layers, reflect prolonged, calmer phases. Compound dunes with ridges in their cores indicate major coastal events or shifts in atmospheric conditions that would have exposed wide sand areas to wind and facilitated dune development. This study demonstrates that the aeolian processes and changes in storminess have played an important role in the genesis of ridge-swale complexes in the Baltic Sea Region.

1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf