Bedload geochemical and petrophysical signature of the Algal and Bohemian streams, James Ross Island, Antarctic Peninsula

This study presents the first geochemical and petrophysical data on the composition of the bedload sediments transported by the Algal and Bohemian Stream, and the latter’s prominent tributary: the Dirty Stream. The catchments of these rivers are partially glacierised, with only 2% and 6% ice cover in the Algal and Bohemian stream catchments, respectively. Therefore, the primary sources of liquid water to these rivers are snowmelt and active layer thawing. This study shows that the Cretaceous marine sedimentary rocks deposited in the back-arc James Ross Basin, which underlies the studied rivers, represent the main constituent of fluvial bedload. This is in contrast to suspended sediment loads, whose composition is a mixture of volcanic rocks from the surrounding James Ross Island Volcanic Group. This also suggests that bedload is only transported for a distance of few hundreds of metres, while suspended sediment load is transported throughout the Algal and Bohemian streams to the sea. It is anticipated that this work will serve as the source of data for further studies from fluvial geomorphology to river ecology.