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Rheological tests of viscous material mixtures used as lithosphere analogues

This dataset contains rheological and density measurements of viscous material mixtures used to simulate the lithosphere in analogue modeling of tectonic processes. Simulating lithospheric deformation occurring in nature over geological time scales requires appropriately scaled materials for the laboratory experiments. Here, we characterize viscous materials that can exhibit Newtonian and/or non-Newtonian behavior depending on the applied strain rate. We conducted rotational tests in controlled shear rate mode (i.e., shear rate was increased while keeping the temperature constant) and temperature ramp tests (i.e., temperature was varied while keeping temperature constant) on eight different materials, including pure Polydimethylsiloxane (PDMS), pure plastiline (Hartum Color Plaxtin Soft), and mixtures of these materials with fillers (iron powder and/or silicone oil). This publication results from work conducted under the transnational access/national open access action at the Laboratory of Experimental Tectonics of the University Roma Tre supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

Rheometric Analysis of Viscous Material Mixtures Used in the Tectonic Laboratory (TecLab) at Utrecht University, Netherlands

This dataset contains measurements of viscous and viscoelastic materials that are used for analogue modelling. Proper density and viscosity scaling of ductile layers in the crust and lithosphere, requires materials like Polydimethylsiloxane (PDMS), to be mixed with fillers and low viscoity silicone oils. Changing the filler content and filler material, the density, viscosity and power-law coefficient can be tuned according to the requirements. All materials contain a large amount of PDMS and all but one a small amount of an additional silicone oil. Adding plasticine or barium sulfate lead to shear thinning rheologies with power-law exponents of p<0.95. Adding corundum powder only has a minor effect on the power-law exponent. Some mixtures also have an apparent yield point but all are in the liquid state in the tested range. In general, the rheologies of the materials are very complex and in some cases strongly temperature dependent. However, in the narrow range of relevant strain rates, the behaviour is well defined by a power-law relation and thus found suitable for simulating ductile layers in crust and lithosphere.

Ring-shear test data of wheat flour used for analogue experiments in the laboratory of the Institute of Geophysics of the Czech Academy of Science, Prague

This dataset provides friction data from ring-shear tests (RST) for wheat flour used as a fine-grained, cohesive analogue material for simulating brittle upper crustal rocks in the analogue labor-atory of the Institute of Geophysics of the Czech Academy of Science (IGCAS). It is characterized by means of internal friction coefficients µ and cohesion C. According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak friction coefficients µP of the tested material is ~0.72, dynamic friction coeffi-cients µD is ~0.67 and reactivation friction coefficients µR is ~0.70. Cohesions of the material range between 27 and 50 Pa. The material shows a minor rate-weakening of ~1.5% per ten-fold change in shear velocity v and a stick-slip behaviour at low shear velocities.

Ring shear test data of iron powder – quartz sand mixture: a new marker material for analog modelling in a CT scanner at Utrecht University (The Netherlands) (EPOS TNA call 2017)

This dataset provides friction data from ring-shear tests (RST) on an iron powder – quartz sand mixture (weight ratio 1:3). This material is used in particular as marker material in analogue experiments that are monitored with CT-scanners in the Tectonic Laboratory (TecLab) at Utrecht University (NL) (Pueyo et al., 2017; 2018). The material has been characterized by means of internal friction coefficients µ and cohesions C as a remote service by the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam in the framework of the EPOS (European Plate Observing System) Transnational Access (TNA) call of the Thematic Core Service (TCS) Multi-scale Laboratories (MSL) in 2017.According to our analysis the material behaves as a Mohr-Coulomb material characterized by a linear failure envelope. Peak, dynamic and reactivation friction coefficients are µP = 0.65, µD = 0.53, and µR = 0.62, respectively. Cohesions C are in the range of 70 to 100 Pa. A minor rate-weakening of ~3% per ten-fold change in shear velocity v is evident.

Ring-shear test data of quartz sand – silicate cenospheres mixtures used for analogue experiments at the Institute of Geophysics of the Czech Academy of Science, Prague

This dataset provides friction data from ring-shear tests (RST) for mixtures of quartz sand and sili-cate cenospheres, which are used for analog experiments in the laboratory of the Institute of Geo-physics of the Czech Academy of Science (IG CAS) (Warsitzka et al., 2021). The mixtures have been characterized by means of internal friction coefficients µ and cohesion C as a remote service by the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam. According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak friction coefficients µP of the tested materials range between 0.55 and 0.75, dynamic friction coefficients µD between 0.47 and 0.60 and reactivation friction coefficients µR be-tween 0.52 and 0.65. Cohesions of the materials vary between 20 and 120 Pa. The materials show a minor rate-weakening of <1.2% per ten-fold change in shear velocity v.

Ring-shear test data of quartz sand used for analogue experiments in the laboratory of the Institute of Geophysics of the Czech Academy of Science, Prague

This dataset provides friction data from ring-shear tests (RST) for a quartz sand used in analogue experiments at the Institute of Geophysics of the Czech Academy of Science (IGCAS) (Kratinová et al., 2006; Zavada et al., 2009; Lehmann et al., 2017; Krýza et al., 2019). It is characterized by means of internal friction coefficients µ and cohesion C.According to our analysis the materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak friction coefficients µP of the tested material is ~0.75, dynamic friction coeffi-cients µD is ~0.60 and reactivation friction coefficients µR is ~0.64. Cohesions of the material range between 90 and 130 Pa. The material shows a minor rate-weakening of <1% per ten-fold change in shear velocity v.

Data supplement to: New analogue materials for nonlinear lithosphere rheology, with an application to slab break-off

This dataset provides strain and strain rate data on mixtures of plasticine, silicone oils and iron powder that has been used in slab break-of analogue experiments in the Tectonic Laboratory (TecLab) at Utrecht University (NL) as an analogue for viscously deforming lithosphere. The materials have been analyzed in a creep and recovery test, applying a parallel plate setup using an AR-G2 rheometer (by TA Instruments).The materials can in general be described as viscoelastic materials with a power-law rheology (see previous work on plasticine-silicone polymer mixtures Weijermars [1986], Sokoutis [1987], Boutelier et al. [2008]). For a couple of the tested materials we find a complementary Newtonian behavior at the low end of the tested stress levels, with a transition to power-law behavior at increasing stress. Furthermore, the materials exhibit elastic and anelastic (recoverable) deformation. The corresponding paper (Broerse et al., 2018) describes the rheology, while this supplement describes the raw data and important details of the measurement setup. The raw data concerns mostly (uncorrected) strain and strain rate data. The rheometry has been performed at the Advanced Soft Matter group at the Department of Chemical Engineering, Delft University of Technology, The Netherlands.

Ring shear test data of feldspar sand and quartz sand used in the Tectonic Laboratory (TecLab) at Utrecht University for experimental Earth Science applications

This dataset provides friction data from ring-shear tests (RST) on feldspar sand and quartz sand, which are used to simulate brittle behaviour in crust- and lithosphere-scale analogue experiments at the Tectonic Laboratory (TecLab), Utrecht University (NL) (Willingshofer et al., 2005; Willingshofer & Sokoutis, 2009; Athmer et al., 2010; Luth et al., 2010; Fernández-Lozano et al., 2011; Leever et al., 2011; Sokoutis & Willingshofer, 2011; Fernández-Lozano et al., 2012; Luth et al., 2013; Munteanu et al., 2013; Willingshofer et al., 2013; Munteanu et al., 2014; Calignano et al., 2015a, b; Ortner et al., 2015; Gabrielsen et al., 2016; Calignano et al., 2017; van Gelder et al., 2017; Wang et al., 2017; Beniest et al., 2018 ). The materials have been characterized by means of internal friction coefficients µ and cohesions C as a remote service by the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam.According to our analysis both materials show a Mohr-Coulomb behaviour characterized by a linear failure envelope. Peak, dynamic and reactivation friction coefficients of the feldspar sand are µP = 0.68, µD = 0.55, and µR = 0.61, respectively. Friction coefficients of the quartz sand are µP = 0.63, µD = 0.48, and µR = 0.52, respectively. Cohesions of the feldspar sand and the quartz sand are in the order of few tens of Pa. A minor rate-weakening of 1% per ten-fold rate change is evident for the feldspar sand, whereas the quartz sand shows a significant rate weakening of ~5%.Further information about materical characteristics, measurement procedures, sample preparation, the RST (Ring-shear test) and VST (Velocity stepping test) procedure, as well as the analysed method is proviced in the data description file. The list of files explains the file and folder structure of the data set.

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