Ascent of volatile-rich felsic magma in dikes: a numerical model applied to deep-sourced porphyry intrusions

Ascent of volatile-rich felsic magma in dikes: a numerical model applied to deep-sourced porphyry intrusions Full article

Journal

Geophysical Journal International
ISSN: 0956-540X

Output data

Year: 2024, Volume: 236, Number: 3, Pages: 1863–1876 Pages count : 14 DOI: 10.1093/gji/ggae027

Tags

Dyke propagation model, Volatile exsolution, Magma viscosity, Buoyancy, Porphyry deposits

Authors

Abdullin R ^1,2 , Melnik O ^3,4 , Rust A ⁵ , Blundy J ⁶ , Lgotina E ² , Golovin S ^1,2

Affiliations

1	Lavrentyev Institute of Hydrodynamics SB RAS , Novosibirsk, Russia
2	Novosibirsk state university , Novosibirsk, Russia
3	Institut des Sciences de la Terre , Grenoble, France
4	Moscow State University , Moscow, Russia
5	University of Bristol , Bristol, UK
6	University of Oxford , Oxford, UK

Dyke propagation is a mechanism for more rapid ascent of felsic magmas through the crust than is possible via diapirs or percolative flow. As it ascends, the magma undergoes complex physical and chemical transformations induced by decompression and cooling. These processes dramatically change the magma density and viscosity, which in turn affect magma ascent rate and the depth at which the dyke arrests. We present a mathematical model of dyke propagation for silicic magmas taking into account the presence of multiple volatile species (H2O and CO2), bubble growth, heat advection and loss, crystallization and latent heat release. We consider conditions for dykes associated with porphyry ore deposits, which may represent an end-member in rapid ascent of felsic magmas from depth. In particular, we simulate the propagation of dykes launched from a deep (900 MPa), volatile-saturated magma source, testing the effects of the magma H2O/CO2 content, temperature and mass on its ascent rate and final emplacement depth. The model predicts short ascent times (hours to days), with a large increase in viscosity at shallow depth, leading to stagnation and solidification of the dyke. Higher initial water content, higher temperature and larger mass of the magma in the dyke promote faster propagation and shallower arrest. Volatile loss from ascending magma remains limited until the stagnation depth, providing a potential mechanism for transfer of deep volatiles to hypabyssal blind intrusions associated with porphyry ore deposits. Our findings are applicable to the problem of silicic magma ascent through the crust more generally.

Abdullin R. , Melnik O. , Rust A. , Blundy J. , Lgotina E. , Golovin S.
Ascent of volatile-rich felsic magma in dikes: a numerical model applied to deep-sourced porphyry intrusions
Geophysical Journal International. 2024. V.236. N3. P.1863–1876. DOI: 10.1093/gji/ggae027 WOS Scopus РИНЦ OpenAlex

Submitted:	Dec 22, 2023
Accepted:	Jan 17, 2024
Published print:	Jan 18, 2024

Web of science:	WOS:001154312800002
Scopus:	2-s2.0-85184075140
Elibrary:	65631951
OpenAlex:	W4391041949

DB	Citing
OpenAlex	2
Elibrary	1
Scopus	1
Web of science	2