Project Details
Projekt
Multi-scale calibrations of electrical properties to probe the deep crust
Applicant
Professorin Dr. Virginia Toy
Subject Area
Geology
Term
since 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 497338887
Our research contributes to, and advances, the likely outcomes of the ICDP-supported project DIVE (Drilling the Ivrea-Verbano ZonE). In it, we will calibrate mid- to lower-crustal metamorphic rocks’ compositions, micro- to macrostructures, and fluid contents to their electrical properties as measured by laboratory, field, and borehole methods across mm- to km-scales. The results will dramatically change geologists’ and geophysicists’ ability to interpret the distribution of mineralized rock types and circulating (e.g. geothermal) fluids within the globally-unique sequence and structures surrounding the DIVE DT-1a and DT-1b drillsites from electrical survey data. They will also be able to be applied more broadly to better understand the distribution of these sort of geological resources at depth in other orogenic belts worldwide.Our methodology comprises; (i) Measurement of the electrical properties of representative rocks from the Ivrea-Verbano Zone both in the laboratory at a range of pressures and temperatures similar to those likely encountered at depth in the boreholes, and in new coupled borehole-surface electrical surveys(ii) Characterisation of the structures and compositions of those same rocks at microscale using electron microscopy and synchrotron computer tomography, at mesoscale through CT scanning of drillcores and automated image analysis of those results, and at kilometer scale by field analysis, (iii) Calibration of computed electrical responses of the observed micro- to macrostructures to our various real measurements allowing prediction of electrical responses of structurally-different materials, and (iv) Calculation of bulk properties of representative volumes of the various heterogeneous materials to dramatically refine the ability to invert for fine structural and lithological variations from coarser resolution surveys. Our work will be complementary to other comparisons of petrological and geophysical datasets (e.g., seismic velocity, density, thermal parameters) planned during DIVE. The overall collaboration will provide an exceptional and novel calibration of petrophysical data to rock mass properties in lower crust and upper mantle lithologies
DFG Programme
Infrastructure Priority Programmes
International Connection
Austria, Switzerland, USA
Co-Investigators
Professor Dr. Andreas Junge; Dr. Kevin Klimm
Cooperation Partners
Dr. Andrew Greenwood; Professor Dr. Matteo Lupi; Dr. Mattia Pistone
