UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Compactive Deformation of Sandstone under Crustal Pressure and Temperature Conditions

Jefferd, M; Brantut, N; Meredith, PG; Mitchell, TM; Plümper, O; (2021) Compactive Deformation of Sandstone under Crustal Pressure and Temperature Conditions. Journal of Geophysical Research: Solid Earth 10.1029/2020jb020202. (In press). Green open access

[img]
Preview
Text
Brantut_Compactive Deformation of Sandstone under Crustal Pressure and Temperature Conditions_AAM.pdf - Accepted version

Download (4MB) | Preview

Abstract

The transition from macroscopically brittle to macroscopically ductile deformation in porous sandstones is known to be pressure dependent, with compactive, ductile behavior occurring only once significant effective pressures have been reached. Within the crust, such effective pressures are associated with burial depths in the range 0.5 to 6 km, where the temperature is likely 35 ◦C to 200 ◦C. To test the importance of such elevated temperature on the strength and deformability of sandstone, a series of constant strain rate, triaxial deformation experiments were performed on three different water saturated sandstones at either ambient temperature or 150 ◦C. For each sandstone, an effective pressure range was used which spanned both the brittle and ductile deformation regimes, up to a maximum of 120 MPa. In the brittle regime, we observed a temperature‐dependent lowering of the yield stress of between 8 and 17%. Within the ductile regime, we observed an even greater reduction in the yield stress of between 9 and 37%. A further notable observation is that the transition from dilatant, brittle behavior to compactive, ductile behavior tends to occur at a lower effective pressure at elevated temperature. The weakening observed at elevated temperature can be explained by a reduction in fracture toughness, which is shown mathematically to cause greater weakening in the ductile regime than in the brittle regime. The apparent reduction in toughness at elevated temperature is potentially driven by a combination of a reduction in surface energy and, to a minor extent, an increase in subcritical crack growth rate.

Type: Article
Title: Compactive Deformation of Sandstone under Crustal Pressure and Temperature Conditions
Open access status: An open access version is available from UCL Discovery
DOI: 10.1029/2020jb020202
Publisher version: https://doi.org/10.1029/2020JB020202
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/10121408
Downloads since deposit
21Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item