| 9040 |
Creator |
4989dd10527e94ef140e45e8c9fb07e6 |
| 9040 |
Creator |
f0065c1ec7d49eb264923727f8e1b946 |
| 9040 |
Creator |
ext-c758a8466e122cc4780cdac824f8518b |
| 9040 |
Creator |
ext-4eca8e0c407f545e75492c1656b90bd2 |
| 9040 |
Creator |
ext-5485b143a77e905098d012806b291d65 |
| 9040 |
Creator |
ext-fbeb5b3240dd7477358da832c1be8842 |
| 9040 |
Date |
2006-02 |
| 9040 |
Is Part Of |
repository |
| 9040 |
Is Part Of |
p02588900 |
| 9040 |
abstract |
The Katla subglacial caldera is one of the most active and hazardous volcanic centres
in Iceland as revealed by its historical volcanic activity and recent seismic unrest
and magma accumulation. A petrologic and geochemical study was carried out on a suite
of mid-Pleistocene to Recent lavas and pyroclastic rocks originated from the caldera.
The whole series is characterised by a bimodal composition, including Fe-Ti transitional
alkali basalts and mildly alkalic rhyolites. Variations in trace-element composition
amongst the basalts and rhyolites show that their chemical differentiation was mainly
controlled by fractional crystallisation and possible assimilation. The petrology
and chemistry of the few intermediate extrusive rocks show that they were derived
from magma mingling or hybridisation. The absence of extrusive rocks of true intermediate
magmatic composition and the occurrence of amphibole-bearing felsic xenoliths support
the hypothesis of partial melting of the hydrated basalt crust as the main process
leading to the generation of rhyolites. The 143Nd/144Nd and 87Sr/86Sr values of Katla
volcanic rocks fit the general isotopic array defined by late Quaternary to Recent
lavas from Iceland. A few rock specimens are distinguished by low 143Nd/144Nd values
suggesting assimilation and mixing of much older crustal material. Despite their similar
whole-rock chemical compositions, the postglacial rhyolitic extrusives differ from
the felsic xenoliths by their glass composition and the absence of amphibole. This,
together with the general chemical trend of volcanic glasses, indicates that the postglacial
rhyolitic extrusives were probably derived by a process involving late reheating and
partial melting of crustal material by intrusion of basaltic magmas. |
| 9040 |
authorList |
authors |
| 9040 |
issue |
4 |
| 9040 |
status |
peerReviewed |
| 9040 |
volume |
69 |
| 9040 |
type |
AcademicArticle |
| 9040 |
type |
Article |
| 9040 |
label |
Lacasse, C.; Sigurdsson, H.; Carey, S. N.; Johannesson, H.; Thomas, L. E. and
Rogers, N. W. (2006). Bimodal volcanism at the Katla subglacial caldera, Iceland:
insight into the geochemistry and petrogenesis of rhyolitic magmas. Bulletin of Volcanology,
69(4) pp. 373–399. |
| 9040 |
label |
Lacasse, C.; Sigurdsson, H.; Carey, S. N.; Johannesson, H.; Thomas, L. E. and Rogers,
N. W. (2006). Bimodal volcanism at the Katla subglacial caldera, Iceland: insight
into the geochemistry and petrogenesis of rhyolitic magmas. Bulletin of Volcanology,
69(4) pp. 373–399. |
| 9040 |
Title |
Bimodal volcanism at the Katla subglacial caldera, Iceland: insight into the geochemistry
and petrogenesis of rhyolitic magmas |
| 9040 |
in dataset |
oro |