Erratum: Sediment thickness and Holocene erosion rates derived from a seismic survey of Hvítárvatn, central Iceland

Abstract

More than 100 km of seismic reflection profiles of the sediment fill in the glacier-dominated lake Hvítárvatn, central Iceland, reveal over 65 m of stratified postglacial sediment in the main depositional basin. Five diagnostic seismostratigraphic units, defined on the basis of acoustic properties tied to lithostratigraphic breaks in sediment cores from the lake, can be traced throughout the sediment fill. Isopach maps of these units exhibit different spatial patterns, suggesting significant changes in the primary sediment delivery systems throughout the Holocene, and implying significant changes in the size and position of Langjökull. The mass of sediment in the lake is estimated to be between 35x1013 g and 121x1013 g. Suspended sediment loss from the lake currently averages 5x1010 g of fine sediment each year. The averageHolocene bedrock erosion rate across the catchment is calculated to be between 2 and 5 cm ka−1, although actual erosion rates under Langjökull are probably much higher, whereas erosion across the non-glaciated portion of the catchment is presumably significantly less.