HR: 1340h
AN: PP43A-0623 [Abstracts]
TI: Sediment thickness and Holocene erosion rates derived from a seismic survey of Hv¡t rvatn, central
Iceland
AU: * Black, J L
EM: jblack@colorado.edu
AF: INSTAAR and Geological Sciences, University of Colorado, 1560 30th St., 450 UCB, Boulder, CO 80309-0450
United States
AU: Miller, G H
EM: gmiller@colorado.edu
AF: INSTAAR and Geological Sciences, University of Colorado, 1560 30th St., 450 UCB, Boulder, CO 80309-0450
United States
AU: Geirsdottir, A
EM: age@hi.is
AF: Dept. of Geosciences, University of Reykjavik, Reykjavik, 101
Iceland
AU: Manley, W
EM: William.Manley@colorado.edu
AF: INSTAAR and Geological Sciences, University of Colorado, 1560 30th St., 450 UCB, Boulder, CO 80309-0450
United States
AU: Bjornsson, H
EM: hb@raunvis.hi.is
AF: Dept. of Geosciences, University of Reykjavik, Reykjavik, 101
Iceland
AB:
More than 100 km of seismic reflection profiles of the sediment fill in the glacier-dominated lake Hv¡t rvatn, 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. Compiled data were entered into a Geographic Information System
(GIS) for further analysis of changes in bathymetry and unit thicknesses, using ArcGIS v8.2. Isopach maps of the
lithostratigraphic units exhibit different spatial patterns, suggesting significant changes in the primary sediment delivery
systems through the Holocene. The mass of sediment in the lake is estimated to be between 55 x 1010 kg and 109 x 1010 kg.
Suspended sediment loss from the lake currently averages 5 x 107 kg of fine sediment each year. From these figures the
average Holocene bedrock erosion rate across the catchment is calculated to be between 2 and 5 cm ka-1.
DE: 3344 Paleoclimatology
DE: 1815 Erosion and sedimentation
DE: 1845 Limnology
DE: 1600 GLOBAL CHANGE (New category)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting