Institute of Geophysics of the CAS, v. v. i.

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Magma emplacement

One of the most important mechanisms of crustal differentiation arises from anatexis, collection of melt and its accumulation in magma chambers. The melt transfer in Earth’s crust is closely spatially associated with rock deformation in all levels of its ascent path (1. separation from its source by melting reactions and grain-scale melt migration in intergranular pockets, 2. coalescence of melt in shear zones, 3. accumulation of melt in large magmatic bodies, and 4. further transport of magma in shallower levels of the Earth’s crust). The melt/magma is transported upwards through complex plumbing systems and rises towards the Earth’s surface, generating various magmatic bodies at different crustal levels (plutons, laccoliths, lava domes). We study the internal fabrics of magmatic (plutonic bodies, lava domes and flows) to understand processes leading to their formation. Shape and internal fabrics of plutons reflect the relationship between the magmatic and tectonic processes at various geotectonic settings.

Our research involves field-oriented structural geology, microstructural analysis and analogue modelling, which is combined with petrologic, geochemical, and numerical studies. Our research is focused on (i) structural geology and tectonics of magmatic bodies and their host rocks, (ii) emplacement mechanisms and development of internal fabrics, (iii) microscale processes controlling the viscous flow, (iv) origin and development of brittle structures in plutonic and volcanic bodies and their relationship with magmatic fabrics and analysis of possible fluid migration pathways.

Magmatic fabric in the Land’s End granite (SW England)

Current research topics:

* Granite plutons – internal fabrics, brittle structures, emplacement processes (Castle Crags and Caribou Mountain plutons in Klamath Mountains, California, USA; Západokrušnohorský granite pluton in Bohemian massif).

* Volcanic bodies – internal fabric patterns in volcanic bodies, such as volcanic domes, laccoliths and lava flows (Cenozoic volcanics of the Bohemian Massif, Three Sisters lava flows in Cascades, California; Phonolite lavas in Wyoming – Missouri Buttes and Devils Tower).

* Analogue modelling – evolution, final shapes and the internal fabric development within various intrusive and extrusive bodies using AMS (anisotropy of magnetic susceptibility) and dyke swarm development in rifted crust.

Research team: Zuzana Roxerová, Prokop Závada, Matěj Machek and Petr Brož.

This research is carried out in cooperation with research teams from both the Czech republic and other countries. Details can be found on web pages of the individual projects.