The rock deformation labs at Brown University and MIT have formed a Collaborative Organization for Rock Deformation (CORD). The primary goal is to encourage and facilitate participation in experimental rock deformation studies by a broader spectrum of scientists within the Earth science community.
If you want to use the CORD laboratories for research, contact one of the PIs from the list below to discuss your project plans.
Matej Pec – mpec[at]mit.edu
Greg Hirth – Greg_Hirth[at]brown.edu
Reid Cooper – reid_cooper[at]brown.edu
Terry Tullis – terry_tullis[at]brown.edu
Brian Evans – brievans[at]mit.edu
Below is a brief description of available apparatus and their capabilities:
1. Equipment in the Rock Deformation Laboratory at MIT EAPS
1.1 Sanchez Technologies Solid Medium Deformation Apparatus: This apparatus (acquired in 2017) is currently installed in newly renovated laboratory space in the Department of Earth, Planetary and Atmospheric Sciences (EAPS) at MIT. It is one of three existing apparatuses of this type world-wide (Fig. 1). The apparatus is hydraulically driven by high-precision syringe pumps and is capable of reaching pressures of up to 2.5 GPa and temperatures of up to 1200˚C in a 1 inch diameter pressure vessel. Typical sample dimensions are 6.33 mm diameter and 12 mm length. Advanced controlling equipment allows precise control of the rate of pressurization, depressurization and heating, as well as constant load control with a nominal resolution of 0.1 MPa. The use of weak salt cells, molten salt and molten glass cells allows for a practical stress resolution of ~10 MPa. Long furnaces (50 mm) minimize temperature gradients in the sample. Data-logging equipment allows for recording of all pertinent variables (axial force, confining pressure, 2x axial displacement, temperature, heating current & voltage) at speeds up to 40kS/s per channel. This apparatus is currently being upgraded with a set of six piezoelectric needle sensors which will eventually allow us to record acoustic emission and conduct wave speed measurements in-situ during high temperature, high pressure deformation.
1.2 Paterson Gas Medium Deformation Apparatus: This apparatus is capable of reaching confining pressures up to 300 MPa and temperatures up to 1200˚C with Argon gas serving as the confining medium. It was designed by Prof. Mervyn Paterson and is one of 13 existing apparatuses of this type world-wide. This apparatus is uniquely suited for high resolution deformation experiments of relatively large samples up to 15 mm in diameter and 30 mm in length thanks to its internal load cell and compensated piston design which eliminates any seal friction from load measurements. The apparatus has a three-zone furnace with temperature gradients of <1 ˚C/mm and a hot-zone ~40 mm in length. Furthermore, it is equipped with a pore pressure system which allows for permeability measurements during deformation as well as introduction of various fluids into the deforming rocks at high pressures and temperatures.
1.3 NER Autolab 3000 Fluid Medium Deformation Apparatus: This apparatus was acquired in 2015 and is currently installed on the 7th floor of MIT EAPS. This triaxial testing machine uses silicon oil as confining medium and allows for simultaneous measurements of permeability, resistivity, acoustic velocities, and mechanical properties of rocks at reservoir conditions. The large sample size (10 cm diameter x 20 cm length) allows up to sixteen acoustic transducers to be attached to the exterior of the rock samples; each may be used in either active or passive modes. Four additional built-in acoustic sensors are located along the sample axis. Acoustic data are collected in continuous streaming mode at a rate of 250 Msample/s. The mean-lithostatic and pore-fluid pressures are independently controlled up to 120 MPa; axial loads up to 4.89 MN can also be applied. An external furnace produces temperatures of up to 120˚C. Tests of mechanical failure, joint reactivation, hydraulic transmissivity and permeability, and hydrofracturing can be performed. We can also measure changes in acoustic wave velocity, locate acoustic emissions, and analyze the moment tensors of the events.
1.4 Permeameters: In addition to the Sanchez, NER and Paterson deformation machines, we use two dedicated permeameters to measure hydraulic transmissivity in very tight rocks (k ≈ 10-20 m2) over periods of time of several weeks at pressures up to 200 MPa. One of these permeameters can also achieve temperatures of 200 ˚C.
2. Equipment in the Rock Deformation Laboratory at Brown University, DEEPS
2.1 Paterson Gas Medium Deformation Apparatus: This apparatus is a newer version of the apparatus described in 1.2. It is equipped with a with a torsion actuator which allows performing high-strain experiments in torsion.
2.2 Griggs-type Solid Medium Deformation Apparatuses: The Brown Rock Mechanics lab houses three Griggs-type deformation apparatus. These apparatuses operate at pressures up to 2.0 GPa and temperatures up to 1200˚C (easily) to 1400˚C. Experiments can be conducted at strain rates from 5e-4/s to 1e-9/s (with a practical limit of around 3e-8/s). Over the last several years, these apparatuses have been updated to allow monitoring of acoustic emissions, drainage of pore fluids, constant stress creep tests, and frictional experiments with variable rig stiffness. Stress measurements are made with a precision of ~1 MPa and an accuracy of ~10 MPa. Samples sizes are approximately 12.5 mm in length with a diameter of 6.25 mm. Experiments can be done in both axial compression and general shear (with shear strains up to ~6 to 7).
2.3 Tullis Large Volume, High Pressure Gas Medium, Rotary Shear Deformation Apparatus: This unique machine, built in 1980 and undergoing continued use and modification, has the design of a high-pressure conventional triaxial apparatus such as built by Paterson, Brace, and Byerlee with a vertical pressure vessel and a hydraulic ram beneath that moves an uncompensated piston into the pressure vessel. The unique aspect is that multiple driving systems are added that rotate the piston, thereby allowing torsional strain of samples or rotary shear of sample pairs. To date it has been used nearly exclusively to study friction using rotary shear of annular samples under confining pressure, employing a unique sliding jacket assembly to separate the gas that provides the confining pressure from the pore space of the sample. For years, this has been used to produce many meters of slip at confining pressures up to 200 MPa. The pressure vessel bore is 76 mm in diameter and 686 mm long, allowing inclusion of several internal transducers such as load and torque cells and a resolver and an LVDT for measuring relative rotational and vertical motion of sample halves. The pressure vessel is designed to operate at 1.0 GPa confining pressure and has been tested to 1.2 GPa. Independent pore pressure control up to 200 MPa is provided to both halves of the sample. This allows pore fluid flow through the sample for slip amounts of 200 mm. Indefinite slip with pore pressure is attainable, if only the top sample half is connected. To date only room temperature experiments have been done, but an internal furnace can allow controlled temperatures of 300˚C. Slip speeds from 0.001 microns/s to 10 mm/s are attainable with the long-available drive system, which can include servo control of slip speeds that substantially stiffen the machine. The ongoing addition of a 100 kW electric servo motor to the drive system, which will be complete by the time this grant will begin, will increase the slip speed to 4.5 m/s (1800 RPM) with positional motor control of 1 nm of slip.
2.4 Ambient-Pressure Deformation Apparatus at Brown: The labs at Brown use and maintain four ambient-pressure deformation apparatus: (1) an Instron 3100/8500 compression-tension, servomechanical-actuator machine; (2) an Instron 1332/8500 rotary shear, compression/tension, servohydraulic machine, (3) a custom designed/built, low-strain/high-strain-resolution reciprocating torsion machine; and (4) a custom designed/built deadweight machine.
(1) Instron 3100/8500: servomechanical actuation allows for high-precision creep, load-relaxation and low-frequency reciprocating uniaxial loading. The apparatus has, in the past, been outfitted with a high-temperature, controlled-atmosphere furnace and a gravity-fed mechanical extensometer and used for flexural attenuation experiments on silicate partial melts [e.g., Gribb and Cooper, 1995] and for load-relaxation studies of halite [Stone et al., 2004] and of olivine [Cooper et al., 2016] single crystals. The apparatus is currently outfitted with a custom designed/built cryostat capable of continuous operation at 100K; it is employed in experiments concerning the creep-affected, low-frequency attenuation in water ice and in ice-hydrate eutectics [e.g., McCarthy et al., 2011; Caswell et al., 2015; McCarthy & Cooper, 2016], as well as in ice fatigue/toughness experiments [Hammond et al., 2018]. With appropriately sized specimens, strain resolution is 10–7.
(2) Instron 1332/8500: at room or elevated temperature and/or one bar controlled composition atmosphere this servohydraulic apparatus allows rapid rotary and axial motion of the piston under electrohydraulic servo control of axial position or load and angular position or torque. The axial load capacity in tension or compression is 11,120 N and the torque capacity is 113 N-m. The rotary stroke is 90 degrees at a maximum speed that corresponds to 300 mm/s for rotary shear of sample pairs of 50 mm diameter. Although our use of this testing machine for the past 20 years has been limited to studies of friction in rotary shear [e.g., Kohli et al., 2011], it is versatile and can be used for many sample configurations.
(3) Custom Designed/Built Torsion Attenuation Apparatus: employing mechanical and extensometer fixturing manufactured from the molybdenum alloy TZM, the apparatus can torque small prismatic specimens of most silicates to perform shear microcreep and, particularly, shear attenuation. Capacitance displacement transducers under digital control allow for a strain resolution of 10–8; controlled-atmosphere furnace allows measurements to be made to 1500ºC for oxygen activities below the Mo:MoO buffer (nominally the same as Fe:FeO) [e.g., Gribb & Cooper, 1998].
(4) Custom Designed/Built Deadweight Creep Apparatus: employing a load train manufactured from oxide or carbide ceramics, a 1650ºC controlled-atmosphere furnace that incorporates a frictionless silicon-oil seal, high precision (in both stress and strain) creep experiments in controlled ¦O2 environments from well below the quartz-iron-fayalite (QIF) buffer to pure oxygen are possible. Stress precision has been emphasized in four-point flexural creep (transient and steady-state) experiments on mantle partial melts.
3. Analytical Equipment: Our laboratories are well equipped for basic characterization of experimental products using optical microscopy, confocal laser microscopy for pore-space and fracture network characterization in 3D, computer integrated polarized (CIP) microscopy for analysis of crystallographic preferred orientation of optically uniaxial minerals, and laser profilometry for analyzing surface roughness. All of these tools are present in-house at no additional cost to the PIs and visitors.
PIs and visitors have furthermore access to a number of state-of-the-art equipment which is available on a per hour charge basis with technical support as detailed in Facilities and Equipment part of this proposal. Nano- and microindentation tools are available in the Department of Materials Science and Engineering at MIT. The Center for Advanced Materials Research (CAMR) at Brown includes a Mechanical Testing Facility that includes four servohydraulic testing apparatus, two of which can operate at elevated temperature in either air (to ~1400oC) or high vacuum (to ~1800oC); these apparatuses operate at ambient pressure. One apparatus can simultaneously apply both axial and torsional loading, though the torsion actuator only operates to limited angles (±50o). A “mechanical microprobe” nanoindenter (Hysitron TriboScope), complete with atomic-force microscopy capability was added to the center in 2004.Micro- and nanofabrication using photolithography and electron beam lithography techniques is available in the Microsystem Technology Laboratories at MIT. Two electron microprobes are available at MIT for quantitative chemical analysis. Both MIT and Brown have excellent machine shops and analytical facilities consisting of a number of SEMs, TEMs, FIB-SEMs and AFMs. These tools are indispensable for conducting state-of-the-art experimental studies.