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Axial Transport and Sources of Fluvial Gravel in Munindalen, Svalbard

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ONDRÁČKOVÁ Lenka HANÁČEK Martin NÝVLT Daniel

Rok publikování 2018
Druh Konferenční abstrakty
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Citace
Popis In order to study the effect of axial transport and lateral inputs on sediment characteristics in High Arctic proglacial streams we focused on the sediments of Munindalen in central Svalbard. Muninelva River is ~6 km long; its channel belt is 50-250 m wide and has a valley-train character, which changes into a braided outwash fan at the mouth. The river is dominantly pebble-cobble gravely along the entire stream with predominant sandstone and limestone clasts from two main sources according to their position in respect to the main stream: I) axial head source - Muninbreen Glacier and its terminal moraine-mound complexes; II) lateral sources - colluvial and alluvial fans, terminoglacial outwash fan from a lateral glacier and bedrock in the channel belt banks. Our results show that the axial head source is crucial for the origin of cobble fraction, whereas lateral sources contribute by large amount of pebble material and overwhelms thus the downstream trend in pebble clasts' roundness. On the contrary, the amount of cobbles transported from the lateral sources is smaller; therefore the downstream trend of cobble clasts roundness is not masked by lateral inputs. Pebbles are highly mobile both in river transport and on lateral fans; therefore lateral inputs hides the downstream roundness trend in Muninelva River sediments, which was not found for cobbles. This study emphasized the importance of material sources on sedimentary characteristics in proglacial streams.
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