Original paper

Experimental study of intragranular fracturing in concentrated magmatic suspensions

Forien, M.; Arbaree, L.; Burgisse, A.; Champallie, R.

Abstract

The intragranularfracturing is a mechanicalphenomenon observed along the borders of sub-volcanicdykes and at the base of lavas flow and experimentally reproduced in concentrated magmatic suspensions (crystal = 54%). A Crystal Size Distribution (CSD) analysis have been performed on polished sections of experimentallydeformed suspensions for experimentsbetween 500°C at 650°C at 3 kbar with a shear strain rate between 8.90xlO˙ 5 S˙lat 5.43xlO˙ 3 S˙l.We show that intragranular fracturing is observed only in sample kerb compatible with shear strain maximum. The temperature is evidenced as a factor of development of intragranular fracturing only throughout the image observations. Those observationsallow to define the role played by shear strain rate too. The exploration of higher temperature rate or again a finer analysis of y on intragranular fracturing in concentrated magmatic suspensionswill allow to complete this study.