Sediment and carbon accumulation rates off the southern coast of Finland

Vallius, Henry

doi:10.5200/baltica.2015.28.08

Cited by 7 publications

(15 citation statements)

References 5 publications

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“…A cosmogenic 10 Be age of 12 500 ± 700 for the ice-margin retreat supports the varve chronology (Rinterknecht et al, 2004). The First Salpausselkä was deposited as a narrow ridge of contiguous meltwater fans and local feeding eskers that were formed along the ice-margin grounding line (Virkkala, 1963;Glückert, 1986;Fyfe, 1990;Kujansuu et al, 1993) in an icecontact lake that was more than 100 m deep in Hanko (Fyfe, 1990). After the ice-margin retreat, the till and subaqueous ice-contact fan deposits were successively covered by glaciolacustrine rhythmically alternating (varved) silt and clay, and postglacial lacustrine poorly bedded clay (Virtasalo et al, 2007(Virtasalo et al, , 2014.…”

Section: Study Areasupporting

confidence: 57%

“…The top of the ice-marginal formation was exposed to waves and eventually to wind as it gradually rose from the sea. The original ridge morphology became truncated and flattened from the top, the glaciolacustrine and postglacial lacustrine silts and clays were removed, and the underlying subaqueous icecontact fan deposits were reworked by wind waves and currents (Virkkala, 1963;Glückert, 1986;Fyfe, 1990;Kujansuu et al, 1993). Fine sand was redeposited as beach ridges on the south side of the peninsula and partially reworked into aeolian dunes (Fyfe, 1990).…”

Section: Study Areamentioning

confidence: 99%

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Submarine groundwater discharge site in the First Salpausselkä ice-marginal formation, south Finland

et al. 2019

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Abstract. Submarine groundwater discharge (SGD) has been implicated as a significant source of nutrients and potentially harmful substances to the coastal sea. Although the number of reported SGD sites has increased recently, their stratigraphical architecture and aquifer geometry are rarely investigated in detail. This study analyses a multifaceted dataset of offshore seismic sub-bottom profiles, multibeam and side-scan sonar images of the seafloor, radon measurements of seawater and groundwater, and onshore ground-penetrating radar and refraction seismic profiles in order to establish the detailed stratigraphical architecture of a high-latitude SGD site, which is connected to the Late-Pleistocene First Salpausselkä ice-marginal formation on the Hanko Peninsula in Finland. The studied location is characterized by a sandy beach, a sandy shore platform that extends 100–250 m seaward sloping gently to ca. 4 m water depth, and a steep slope to ca. 17 m water depth within ca. 50 m distance. The onshore radar and offshore seismic profiles are correlated based on unconformities, following the allostratigraphical approach. The aquifer is hosted in the distal sand-dominated part of a subaqueous ice-contact fan. It is interpreted that coarse sand interbeds and lenses in the distal fan deposits, and, potentially, sandy couplet layers in the overlying glaciolacustrine rhythmite, provide conduits for localized groundwater flow. The SGD takes place predominantly through pockmarks on the seafloor, which are documented on the shore platform slope by multibeam and side-scan sonar images. Elevated radon-222 activity concentrations measured 1 m above seafloor confirm SGD from two pockmarks in fine sand sediments, whereas there was no discharge from a third pockmark that was covered with a thin organic-rich mud layer. The thorough understanding of the local stratigraphy and the geometry and composition of the aquifer that have been acquired in this study are crucial for successful hydrogeological modelling and flux studies at the SGD site.

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Section: Study Areasupporting

confidence: 57%

Section: Study Areamentioning

confidence: 99%

Submarine groundwater discharge site in the First Salpausselkä ice-marginal formation, south Finland

et al. 2019

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“…Due to the strength of the signal the gammaspectrometry method is very well usable in the Gulf of Finland and the Gulf of Bothnia along the trajectory of the fall out of the Chernobyl nuclear power plant accident. Results on accumulation rates have been published amongst other GTK results from the different cruises, but especially in Vallius (2015b). Other results especially from the third cruise have been published in several different papers (Vallius 1999;Vallius 1999b;Vallius 2012;Vallius, Leivuori 1999;Vallius, Leivuori 2003).…”

mentioning

confidence: 86%

“…First data of these studies were published from the western part of the area where indications of permanent seafloor anoxia in coastal accumulation basins were reported (Vallius 2006). Maps with arsenic and heavy metal distribution in the modern soft surface sediments of the coastal area were later published by Vallius (2009) and an evaluation of the quality of the sediments based on American sediment quality guidelines a few years later (Vallius 2015b). The issue of the quality of the sediments has grown in importance during the last years mainly due to the increased activities at sea, which are affecting the seafloor, and knowledge of the state of the sediments is then crucial.…”

Section: Later International Projectsmentioning

confidence: 99%

Sediment geochemistry studies in the Gulf of Finland and the Baltic Sea : a retrospective view

Vallius¹

2016

Baltica

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Our recent knowledge of the chemistry of the seafloor of the Baltic Sea has been gained during the last century only and most of it during the last three to four decades. When thinking about the start of the industrialization it seems unfortunately late. However, fortunately the seafloor archives all environmental changes in the sedimentary column like pages in a book and they can be later observed and interpreted. The Geological Survey of Finland has performed seabed geochemistry studies for decades. The first studies were performed onboard cruises of the old research vessel Aranda and later on the new Aranda as well as on the surveys on our own vessels Geola, Kaita, and Geomari. A great part of the work has been done as collaboration in international research programmes, but especially the Marine Ecogeological Patrol by the A. P. Karpinsky Russian Geological Research Institute has been of great importance for Gulf of Finland studies and as a trigger for later studies in the Gulf of Finland as well as the Baltic Sea.

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“…Bedrock in the northern archipelago of the GoF consists of Paleoproterozoic crystalline basement rocks. Due to complex and fragmented sea floor, many small semi-enclosed basins are characteristic in this area [42,43].…”

Section: Research Area and Sediment Samplingmentioning

confidence: 99%

Phosphorus exchange in eutrophied coastal brackish water sediments—sorption pattern, potential and factors affecting them

et al. 2019

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Phosphorus (P) exchange in clayey mud sediments was investigated with desorption-sorption isotherms at 22 coastal sites in the eutrophied brackish Gulf of Finland, the Baltic Sea. The aim was to gain information on P sorption potential and pattern of oxygenated surface sediments and to elucidate factors explaining them. Modified Freundlich equation was fitted to the isotherm data and used for calculation of the P exchange parameters EPC 0 (equilibrium P concentration at zero net sorption), k EPC0 , k 15 and k 100 (P buffering capacities at early, middle and high sorption stages, respectively). They were further used to assess the P sorption potential and pattern of the sediments. Sediment properties explaining the P sorption potential at different sorption stages were identified. The greatest sorption potentials were recorded in originally poorly oxic sediments in the inner archipelago with accumulated fine particulate material, high in adsorbents for P, transported from the watersheds. After oxygenation, they were high in amorphous Fe-oxyhydroxides, which explained their efficient P sorption (k EPC0 > 1.32 l g −1). Poorer P sorption (k EPC0 0.45-0.84 l g −1) was recorded in fine sediments abundant in Al-oxyhydroxides, presumably due to their higher original P occupation degree. The lowest sorption potentials were found in the outer archipelago sediments. Their lowest specific surface areas and highest original P contents referred to scarcity of adsorbents and high occupation degree of the existing ones. These results suggest that the coastal clayey mud sediments investigated possess high P sorption potential, which can be markedly diminished by eutrophicationinduced hypoxia but recovered if oxygen conditions improve.

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Sediment and carbon accumulation rates off the southern coast of Finland

Cited by 7 publications

References 5 publications

Submarine groundwater discharge site in the First Salpausselkä ice-marginal formation, south Finland

Submarine groundwater discharge site in the First Salpausselkä ice-marginal formation, south Finland

Sediment geochemistry studies in the Gulf of Finland and the Baltic Sea : a retrospective view

Phosphorus exchange in eutrophied coastal brackish water sediments—sorption pattern, potential and factors affecting them

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