Petrophysical properties are directly connected to the minerals which form the rock. Mafic rocks in the Earth’s crust containing minerals such as pyroxene, amphibole, and feldspar, have a lower density than, e.g., an eclogite, which contains garnet and omphacite. The geometric arrangement of the minerals, their abundances, and the structure in rocks influences many other bulk rock petrophysical properties such as compressibility, shear moduli, porosity, and permeability. These properties directly affect the seismic signals which are obtained by seismologists from geophysical measurements. For a detailed insight into geological processes at depth it is therefore crucial to understand how mineral reactions affect the seismic signal so that geophysical data can be interpreted correctly. By direct petrophysical measurements on minerals and rocks found in exhumed rocks and using averaging techniques by acknowledging the entire field relations, we may develop a more complete understanding of how small scale petrophysical properties from a natural observation influence the seismic signal that may be recorded at the Earth’s surface. By doing so, we may also better understand what happens at depth beneath an orogen.

Further reading: Zertani et al. (2019a); Zertani et al. (2019b); Zertani et al. (2020);