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Mechanical properties of simulated Mars materials: gypsum-rich sandstones and lapilli tuff

November 21, 2013

Observations by the Mars Exploration Rover (MER) Opportunity, and other recent studies on diagenesis in the extensive equatorial layered deposits on Mars, suggest that the likely lithologies of these deposits are gypsum-rich sandstones and tuffaceous sediments (for example, Murchie and others, 2009; Squyres and others, 2012; Zimbelman and Scheidt, 2012). Of particular interest is how the diagenesis history of these sediments (degree of cementation and composition) influences the strength and brittle behavior of the material. For instance, fractures are more common in lower porosity materials under strain, whereas deformation bands, characterized by distributed strain throughout a broader discontinuity in a material, are common in higher porosity sedimentary materials. Such discontinuities can either enhance or restrict fluid flow; hence, failure mode plays an important role in determining the mechanics of fluid migration through sediments (Antonellini and Aydin, 1994; 1995; Taylor and Pollard, 2000; Ogilvie and Glover, 2001). As part of a larger study to characterize processes of fault-controlled fluid flow in volcaniclastic and gypsum-rich sediments on Mars, we have completed a series of laboratory experiments to focus on how gypsum clast content and degree of authigenic cementation affects the strength behavior of simulated Mars rocks. Both axial deformation and hydrostatic pressure tests were done at room temperature under dry conditions.

Citation Information

Publication Year 2013
Title Mechanical properties of simulated Mars materials: gypsum-rich sandstones and lapilli tuff
DOI 10.3133/ofr20131242
Authors Carolyn Morrow, David Lockner, Chris Okubo
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2013-1242
Index ID ofr20131242
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center