OCGC Seminar - Bridging volcanic gas monitoring and the geological context of ore deposits: from Italy to Canada


Dr. Philippe Robidoux, 
Visiting Researcher at the University of Ottawa  

Thursday, October 20th 

123 Marion Hall 
University of Ottawa  



Volatiles in volcano-magmatic systems are investigated for their abundance, role and behavior in three general depth zones: (1) eruption and shallow magma interaction levels with atmosphere and hydrosphere, (2) crustal stagnation and differentiation of magma and (3) root zone where magma is generated and rises in the mantle.

I have investigated the abundance of primitive volatile contents (H2O, CO2, S, Cl) in these different «depth zones» in order to quantify the volatile budget before and after they are discharged as gases to the atmosphere during eruptive events and quiescent degassing periods.

To fully respond to these tasks, I therefore present different techniques I have learnt from the Istituto Nazionale de Geofisica e Vulcanologia (INGV) in Italy, where I specialized in a multidisciplinary melt inclusion/gas monitoring approach that combines (A) field instrumentations and (B) laboratory facility. These different approaches integrate data on volatiles from melt inclusions and temporal variation of gases from the central crater plume and fumarole fields. Field surveys were carried out in different countries found along volcanic arc environments (Italy, Mexico, Nicaragua, Costa Rica and Chile).

Sooner or later, when geologists try to spatially and temporally evaluate the volatile budget of volcanoes, they realize that during crystallization of magmas in the crust, exsolution and discharge of most volatiles feed hydrothermal systems. After all, when volatiles are lost and concentrated in the upper parts of magma reservoirs, they participate in a complex series of chemical reactions with mixed fluids and therefore can induce mineralization of different types of economic ore deposits, such as in porphyry-epithermal mineral systems. Canada has a historical expertise in mineral exploration and entire structures of mineralized «fossil» magmatic environments are found in this country. Therefore, in collaboration with U. Ottawa, I decided to develop an approach to improve the model of magmatic fluid circulations in active and fossil volcanic environments which will be resumed at the end of this presentation.