Total sediment budget of a transgressive barrier-spit,Skallingen, SW Denmark: A review |
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| Authors: | Christian Christiansen Troels Aagaard Jesper Bartholdy Merete Christiansen Jørgen Nielsen Niels Nielsen |
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| Institution: | 1. Institute of Geography, University of Copenhagen , ?ster Voldgade 10, 1350 , Copenhagen K. , Denmark E-mail: cc@geogr.ku.dk taa@geogr.ku.dk jb@geogr.ku.dk jn@geogr.ku.dk nn@geogr.ku.dk jtp@geogr.ku.dk nv@geogr.ku.dk;2. Wind Energy Department, Ris? National Laboratory , Frederiksborgvej 399, Build. 125. P.O. 49, 4000 , Roskilde , Denmark E-mail: merete.bruun.christiansen@risoe.dk |
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| Abstract: | Average sea-level rise in the northern part of the Danish Wadden Sea has been 1.3 mm a?1 during the last 100 years but during the last 25 years a rise of 4.2 mm a?1 was observed. Concurrent with the recent sea-level rise the Skallingen barrier spit has migrated landward by 3–5 m a?1. Long term sediment budgets for each of the morphological units involved in the migration are reviewed (e.g. onshore in the shore face +90.000 m3 a?1, longshore -641.000 m3 a?1, foredunes +65,000 m3 a?1, overwash fan including shorenormal dunes +11,000 m3 a?1, spit terminus -96,000 m3 a?1, tidal flat + 10,000 m3 a?1 and backbarrier salt marsh +33,000 m3 a?1) and used to establish the relative importance of sediment transport processes involved in barrier migration. Strong interannual variations exist in the long term budget making evaluation of barrier behaviour based on short term measurements doubtful. In a cross shore sense the barrier spit is accreting in spite of the sea level rise. This is specially pronounced at an active overwash fan. However, due to substantial sediment losses to longshore transport the barrier, gets narrower and shorter during its transgressive behaviour. This may indicate that preservation of barriers in the geological record during rapid sea level rise is promoted when sediment loss to longshore transport is insignificant. |
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| Keywords: | Barrier spit transgression sediment budget Skallingen Denmark |
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