Jökull - 01.01.2005, Side 120

Erratum: Sediment thickness and Holocene erosion rates
derived from a seismic survey of Hvítárvatn, central Iceland.
Jessica Black1, Gifford Miller1, Áslaug Geirsdóttir2, William Manley1 and Helgi Björnsson2
1Institute of Arctic and Alpine Research and University of Colorado, Boulder, Colorado 80309, USA
2Institute of Earth Sciences, University of Iceland, Askja, Sturlugata 7, IS-101 Reykjavík, Iceland
Jessica.L.Black@colorado.edu; gmiller@colorado.edu; age@hi.is; William.Manley@colorado.edu; hb@raunvis.hi.is
In our paper, there were inaccuracies in both Tables
1 and 2. These were in part related to the transcrip-
tion of the original digital files. However, the esti-
mated mass of sediment accumulation in the lake was
erroneously based on the average wet bulk density of
the sediment, rather than the dry bulk density. Both
of these errors are corrected on the new versions of
the tables included with this note. The main impact
of these changes is that the calculated erosion rates
are reduced by 20–35%. These changes do not effect
the primary conclusions of the paper, that the average
Holocene erosion rates in Iceland are relatively low.
Table 1. Calculated sediment volume and sediment mass derived from the seismic survey of Hvítarvatn.
– Setrúmmál og þyngd reiknað út frá upplýsingum af endurvarpsmælingum á Hvítárvatni.
Sediment within the Seismic Survey area Whole lake estimates
Seismic Whole-
Hvítárvatn Seismic Seismic Seismic Seismic Survey Southern lake
Unit 1 Unit 2 Unit 3 Unit 4 Total Shallows LIA Scour total
Area (m2) 9.3x106 9.3x106 9.3x106 9.3x106 9.3x106 13.7x106 6.3x106 29.3x106
Vol. (m3) 11.7x107 2.6x107 9.7x107 8.1x107 32.1x107 13.3x107 19.1x107 64.5x107
Mass1 (g) 13.8x1013 3.1x1013 11.4x1013 9.6x1013 37.9x1013 15.7x1013 22.5x1013 76.1x1013
1Based on an average dry bulk density of 1.18 g cm−3 through the sediment fill in Hvítárvatn.
Table 2. Holocene erosion rates for the Hvítarvatn catchment based on sediment accumulation within the lake
and estimates of suspended sediment loss through the outflow stream Hvítá. – Rofhraði á vatnasviði
Hvítárvatns á nútíma byggt á setupphleðslu innan vatnsins og mati á svifaur sem tapast við útstreymi
Hvítárvatns í Hvítá.
Sediment fill in Estimated sediment fill Total fill since Suspended Total sediment
Units 2,3 and 4 since deglaciation regional sedim. lost delivered by
of the Seismic Survey Southern shallows LIA Scour deglaciation from lake catchment
Volume (m3) 20.4x107 8.5x107 12.2x107 41.1x107
Mass (g) 24.1x1013 10.0x1013 14.4x1013 48.5x1013 50.8x1013 99.3 x1013
Erosion 1.1 cm ka−1 2.2 cm ka−1 4.5 cm ka−1
rate1 (min. rate) (max. rate)
1Based on an average bulk density of bedrock in the Hvítárvatn catchment of 2.7 g cm−3.
120 JÖKULL No. 55