The lateral growth and coalesence of magma systems royalsocietypublishing.org/journal/rsta Juliet Biggs1 and Catherine Annen1,2 1School of Earth Sciences, University of Bristol, Queen’s Road, Bristol, BS8 1RJ, UK Research 2Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, Cite this article: Biggs J, Annen C. 2019 The ISTerre, 38000 Grenoble, France lateral growth and coalesence of magma JB, 0000-0002-4855-039X systems . Phil.Trans.R.Soc.A377: 20180005. http://dx.doi.org/10.1098/rsta.2018.0005 Thermal and mechanical models of magma reservoir growth need to be reconciled with deformation patterns and structural relationships observed at Accepted: 16 October 2018 active magma systems. Geophysical observations provide a series of short time-scale snap-shots (100– One contribution of 15 to a Theo Murphy 102 years) of the long-term growth of magmatic 3 6 meeting issue ‘Magma reservoir architecture bodies (10 –10 years). In this paper, we first review evidence for the growth of magmatic systems along and dynamics’. structural features and the associated deformation patterns. We then define three distinct growth stages, Subject Areas: (1) aligned melt pockets, (2) coalesced reservoirs, (3) volcanology, geophysics highly evolved systems, which can be distinguished using short-term surface observations. We use Keywords: two-dimensional thermal models to provide first- thermal models, surface deformation, order constraints on the time scales and conditions transcrustal magmatic systems associated with coalescence of individual magma bodies into large-scale reservoirs. We find that closely spaced intrusions (less than 1 km apart) can develop Author for correspondence: combined viscoelastic shells over time scales of 10s kyr Juliet Biggs and form laterally extensive mush systems over time e-mail:
[email protected] scales of 10–100 kyr.