Shock compression of dolomite

Abstract

Shock compression studies on a dolomite rock (ρ0 = 2.84 g/cm3) have been conducted in the stress range 150–450 kbar. The entire loading and unloading history as well as the Hugoniot properties were investigated, using continuous recording piezoresistant stress gages. The following results were obtained: (1) The Hugoniot shock velocity‐particle velocity curve shows deviation from linearity in a region corresponding to stresses between 100 and 250 kbar. (2) Comparison of the experimental Hugoniot with a Murnaghan pressure‐volume relation extrapolated from low‐pressure ultrasonic data indicates anomalous compressibility. (3) Unloading experiments from peak stresses between 180 and 300 kbar show excessive hysteresis in the stress‐volume plane. (4) Shock compression to a peak stress in excess of 400 kbar is followed by immediate stress relaxation. (5) Overtaking relief wave velocities measured at the Hugoniot state are found to be considerably higher than extrapolated bulk sound velocities. Our interpretation of the results is a rate‐dependent, low‐ to high‐density phase transformation occurring in the stress range 100–500 kbar.

Equation of state of dolomite from shock Hugoniot and static compression studies

“…The Hugoniot data reported in Grady et al [5], although consistent with earlier data, exhibits more scatter. Measurements in this study lacked the long path length necessary to higher resolution Hugoniot state assessment.…”

“…The materials tested were reported to be greater than 95% dolomite mineral and with near dolomite stoichiometry. Further Hugoniot data are reported by Kalashnikov et al [4] and by Grady et al [5]. The latter was Blair dolomite from a Martinsburg, West Virginia Quarry.…”

“…Acceleration wave features on decompression are identified as (1) release arrival from back surface of the aluminium flier, and (2) onset of reverse transformation of a high-pressure phase. Consensus of the experiment, and analysis of the experimental data, is that shock compression of dolomite to the 40 GPa Hugoniot pressure level results in post-Hugoniot state, time-delayed transformation to a higher density phase [5]. Reverse transformation occurs on decompression at about 20-25 GPa.…”

Structural and mechanical properties of dolomite rock under high pressure conditions: A first‐principles study

“…The static studies concluded that dolomite is stable until 16 GPa at 300 K, with CO 3 group being notably incompressible. However, shock-compressed dolomite shows the presence of a rate dependent low-to high-density phase transformation initiating near 27 GPa [19]. A high-pressure phase transformation of dolomite was also suggested to occur near 9 GPa in the experimental work of Liu and Lin [21].…”

“…On the other hand, shock data (shock wave experiments) extends to 115 GPa on dolomite [19,20]. The static studies concluded that dolomite is stable until 16 GPa at 300 K, with CO 3 group being notably incompressible.…”