Rock analogs for structural geology

This is a compilation of the properties of different analog materials used to simulate deformational processes in structural geology. Such experiments are often called analog or analogue models. The organization of this page follows the review of rock analog materials in structural geology and tectonics of Reber et al. 2020.

Materials used to simulate upper crustal deformation

These materials need to exhibit brittle deformation upon failure as well as elastic and viscous deformation before failure.

Materials that simulate upper crustal deformation

Material	Applications	Studies
Plexiglas and glass	Plexiglas and glass is useful for many applications. Some of which are: stress analysis of grains fracturing earthquake dynamics	Erdogan & Sih 1963; Thomas and Pollard 1993; Cooke & Pollard,1996; Daniels & Hayman, 2008; Lu, Lapusta & Rosakis, 2007; Owens & Daniels, 2011; Rubino, Rosakis, & Lapusta, 2019
Gelatin	Gelatin has been used to simulate: tensile fracturing thrust faults dyke and sill emplacement	Bot, vanAmerongon, Groot, Hoekstra, & Agterof, 1996; Brizzi, Funiciello, Corbi, Di Giuseppe, & Mojoli, 2016; Canon-Tapia and Merle, 2006; Corbi et al., 2011; Corbi et al., 2013; Di Giuseppe et al., 2009; Hyndman & Alt, 1987; Kavanagh, Menand, & Daniels, 2013; Kavanagh, Menand, & Sparks, 2006; Kervyn, Ernst, de Vires, Mathieu, & Jacobs, 2009; Kobchenko et al., 2014; Lee, Reber, Hayman, & Wheeler, 2016; Menand & Tait, 2002; Pollard, 1973; Rivalta, Bottinger, & Dahm, 2005; Touvet, Balmforth, Craster, & Sutherland, 2011; van Otterloo & Cruden, 2016
Foam	Foam is mostly used as an analog simulating elastic loading on the crust between earthquake events. If the foam used has a low stiffness, it can be dynamically scaled to preexisting fault surfaces' and earthquake cycles	Anooshehpoor & Brune, 1999; Anooshehpoor, Heaton, Shi & Brune, 1999; Brune,1973; Caniven et al., 2015; Rosenau et al., 2017; Rosenau, Lohrmann, & Oncken, 2009; Rosenau & Oncken, 2009
Clays	Clay is used to simulate deformation in the upper crust through distributed deformation and localized failure. The properties of clay depend on the mineralogy, grain size distribution and water content.	Bonanno, et al., 2017; Bonini et al., 2016; Cooke and van der Elst, 2012; DeGroot & Lunne, 2007; Eisenstadt & Sims, 2005; Hatem, Cooke, & Toeneboehn, 2017; Henza, Withjack, & Schlische, 2010; Kenny, 1967; Mitra & Paul, 2011; Paul & Mitra, 2013; Toeneboehn, 2017; Toeneboehn, 2018; White, 1949; Withjack, Henza, & Schlische, 2017

Materials used to simulate deformation of the lower crust and mantle

Various fluids are used to simulate deformation of the lower crust and mantle, such as: linear, non-linear, and yield stress fluids.

Fluid type	Material	Application	Studies
Linear viscous fluids	Silicone Oils/Polymers	Silicone oils/polymers can have varying viscosities, which can be changed by adding fillers or colic acid. In combination with brittle model materials, silicone oils/polymers can investigate many processes in salt tectonics, including the deformation of sediments adjacent and above a salt body.	Boutelier, Schrank, & Cruden, 2008; ten Grotenhuis et al., 2002; Weijermars, 1986; Brun & Fort, 2004; Brun & Mauduit, 2009; Cobbold, Szatmari, Demercian, Coelho, & Rossello, 1995; Dooley & Hudec, 2017; Dooley et al., 2009; Dooley, Jackson & Hudec, 2013; Dooley, Jackson & Hudec, 2015; Duffy et al., 2018; Letouzey, Colletta, Vially & Chermette, 1995; Smit, Brun, Fort, Cloetingh, & Ben-Avraham, 2008; Vendeville & Jackson, 1992; Weijermars, 1986; Weijermars, Jackson, & Vendeville, 1993
Linear viscous fluids	Honey*	Honey, glucose syrup, and molasses exhibit strain independent deformation. The viscosity depends on the sugar content and temperature of the material. This makes them suitable to simulate the lower crust and mantle. *Honey can also be used as a non-linear viscous fluid under certain conditions.	Schellart, 2011
Linear viscous fluids	Glucose Syrup	Honey, glucose syrup, and molasses exhibit strain independent deformation. The viscosity depends on the sugar content and temperature of the material. This makes them suitable to simulate the lower crust and mantle. *Honey can also be used as a non-linear viscous fluid under certain conditions.	Schellart, 2011
Linear viscous fluids	Molasses	Honey, glucose syrup, and molasses exhibit strain independent deformation. The viscosity depends on the sugar content and temperature of the material. This makes them suitable to simulate the lower crust and mantle. *Honey can also be used as a non-linear viscous fluid under certain conditions.	Schellart, 2011
Linear viscous fluids	Gum Rosin	Gum rosin was used to study thermomechanical processes in the lithospheric mantle.	Cobbold & Jackson, 1992
Linear viscous fluids	Water	Water has been used to model any low viscosity material.	Paola et al., 2006
Non-linear viscous fluids	Silicone Oils/Polymers	Silicone is also used as a non-linear viscous material by adding high amounts of filler. The most common filler material used is plasticine.	Boutelier et al., 2008; Rudolf, Boutelier, Rosenau, Schreurs, & Oncken, 2016
Bingham fluid	Paraffin Wax	Paraffin wax can be used in analog experiments as a linear or non-linear yield stress fluid. By mixing paraffin wax with petrolatum, the yield stress, shear thinning, and shear softening behavior can be modified.	Duarte et al., 2014; Rossetti et al., 1999
Bingham fluid	Petrolatum	Petrolatum is commonly used as: A filler with paraffin wax A lubricant At this time, pure petrolatum has not been used for analog material.	Cobbold, 1975; Duarte et al., 2014; Neurath and Smith, 1892
Hershel-Bulkley fluid	Carbopol	Carbopol has been used in analogue models of: Gravity driven flow Rayleigh-Benard-like convection Localized shear zones Thermal intrusions Semi-brittle processes	Balmforth & Rust, 2009; Birren & Reber, 2019; Davaille et al., 2013; Di Federico et al., 2017; Reber et al., 2015; Schrank, Boutelier, & Cruden, 2008

Materials used to simulate deformation of the middle crust

Composite Model Materials

Composite materials combine phases with different physical properties. A common composite mixture contains dry granular materials and fluids. These analog materials have been used:

Sediment transport using low viscosity fluids
Dynamics in the middle crust employing high viscosity fluids
Stick-slip dynamics
Strain softening and hardening processes

The most commonly used granular materials in composite mixtures are:

Sand
Glass beads
Acrylic discs

Common fluids used in composite mixtures are:

Carbopol
Silicone
Wax, which can behave as a brittle or viscous material depending on the melting temperature

Visco-elasto-plastic model materials

Visco-elasto-plastic deformation exhibits a combination of elastic, viscous, and plastic deformation at the same time. Various asphalts and bituminous materials demonstrate visco-elasto-plastic deformation but they are rarely as modeling materials.Common modeling materials demonstrating complex rheology are;

Carbopol
Kaolinite clay