Seminar - News and views on host inclusion barometry - Matteo Alvaro

Lundi 19 mars 2018, 10 h 30

IMPMC - Sorbonne Université - 4 place Jussieu, 75005 Paris, tour 23, 4e étage, couloir 22-23, salle 401

Matteo Alvaro - University of Pavia

Abstract

Protected by their host minerals that prevent post-formation alteration, solid fluid and melt inclusions preserve a geological record fundamental for the correct interpretation of processes occurring at depth within the Earth that otherwise would remain invisible at the whole rock scale. Recent developments of experimental protocols and theoretical tools have resulted in many new and more detailed methods to extract this information.
We can now collect crystallographic data on crystalline solid-state inclusions “in situ” while still entrapped in their mineral host by means of x-ray diffraction and micro-Raman spectroscopy. Interpretation of these results using elasticity theory (e.g. Equation of State) ab-initio simulation (e.g. DFT) and numerical simulation (e.g. FEM) allows us place crucial constraint to unravel several fundamental geological processes. For example, we can shed light on possible formation processes for host-inclusion systems investigating their reciprocal crystallographic orientation. We can determine the remnant strains on the inclusions to infer the strains at the moment of entrapment in the host at depth within the Earth thus providing constraints on the environment of growth for the inclusion and the host at different scales from the micrometric sub-micrometric crystal size to the metric outcrop size. Examples of the crystallographic tools employed to retrieve this information will be illustrated for some geological relevant cases.