| 9079 |
Creator |
169f034520be3a0d0aff86e4441f6f0e |
| 9079 |
Creator |
d20cef2603fde6377721d3c97ed06c20 |
| 9079 |
Creator |
ext-4a9ae3edbf524520d800ff838ac5a2bb |
| 9079 |
Creator |
ext-684d20f92ed7e9c3e50ed8fedaa7bccb |
| 9079 |
Creator |
ext-8465b504cfa00fa8e92a9aaaa727294d |
| 9079 |
Creator |
ext-8b640c8f7839b9e42059163e7798eb32 |
| 9079 |
Date |
2006-11 |
| 9079 |
Is Part Of |
p0012821X |
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Is Part Of |
repository |
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abstract |
This study presents U and Li isotope and major and trace element data for the dissolved
load, suspended particulates and bedload for Icelandic rivers draining predominantly
basaltic catchments. Physical erosion rates range from 920 to 2084 t/km2/yr, with
the higher values associated with glacier-fed rivers. Chemical erosion rates range
from 45 to 91 t/km2/yr, with lower rates being associated with glacier-fed rivers.
Uranium activity ratios, (234U/238U), are close to secular equilibrium in the suspended
and bedloads, but all dissolved load samples show values greater than unity, ranging
from 1.13 to 2.41. The highest (234U/238U) values are found in glacier-fed rivers,
and can be attributed to α-recoil effects, as grinding by glaciers locally enhances
rates of physical weathering. Activity ratios in glacial rivers decrease with distance
from the glacial source due to input from non-glacial tributaries which have high
levels of dissolved uranium and lower activity ratios. In contrast, in non-glacial
rivers, uranium activity ratios increase with distance downstream due to continued
weathering in soils and of bedrock. The δ7Li value of the suspended load is always
lower than that of the bedload due to preferential retention of 6Li in secondary minerals
during weathering. In turn, the δ7Li value of the dissolved load is always greater
than that of the bedload, ranging from 17.0 to 43.7‰. δ7Li for the dissolved load
decreases with increasing levels of dissolved silicon, and the saturation index of
secondary minerals, which suggests that δ7Li decreases with increasing chemical weathering.
There is no correlation between δ7Li values and uranium activity ratios for the dissolved
load for non-glacial rivers, but for glacier-fed rivers there is an increase in δ7Li
with increasing (234U/238U), suggesting that where physical comminution of mineral
grains by glaciers is high, chemical weathering is suppressed, and vice-versa. |
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authorList |
authors |
| 9079 |
issue |
1-2 |
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status |
peerReviewed |
| 9079 |
volume |
251 |
| 9079 |
type |
AcademicArticle |
| 9079 |
type |
Article |
| 9079 |
label |
Pogge von Strandmann, P. A. E; Burton, K. W.; James, R. H.; van Calsteren, P. ;
Gislason, S. R. and Mokadem, F. (2006). Riverine behaviour of uranium and lithium
isotopes in an actively glaciated basaltic terrain. Earth and Planetary Science Letters,
251(1-2) pp. 134–147. |
| 9079 |
label |
Pogge von Strandmann, P. A. E; Burton, K. W.; James, R. H.; van Calsteren, P. ; Gislason,
S. R. and Mokadem, F. (2006). Riverine behaviour of uranium and lithium isotopes
in an actively glaciated basaltic terrain. Earth and Planetary Science Letters, 251(1-2)
pp. 134–147. |
| 9079 |
Title |
Riverine behaviour of uranium and lithium isotopes in an actively glaciated basaltic
terrain |
| 9079 |
in dataset |
oro |