Single-crystal elastic properties of lawsonite and their variation with temperature

Details Single-crystal elastic properties of lawsonite and their variation with temperature Single-crystal elastic properties of lawsonite and their variation with temperature

Apr 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003pepi..136..107s&link_type=abstract

Physics of the Earth and Planetary Interiors, Volume 136, Issue 1-2, p. 107-118.

Physics

6

Scientific paper

We have measured the elastic wave velocities and single-crystal elastic moduli of lawsonite (CaAl2(Si2O7)(OH)2.H2O) by Brillouin spectroscopy at high temperatures to 450°C and at room pressure. Lawsonite is generally characterized by high longitudinal (vP) and shear (vS) elastic wave velocities. A number of the elastic properties increase with increasing temperature, including the shear modulus, G (∂G//∂T=+2.01GPa/100K), and the aggregate velocities vP and vS. These anomalous properties are likely related to a displacive phase transition at ~0°C. This is supported by the small value of the elastic modulus c66 (18(1)GPa at room temperature), and the fact that c66 softens as temperature is decreased approaching the ~0°C phase transition. The anomalous behavior in c66 leads to a decrease in vP/vS and Poisson's ratio with increasing temperature at 1atm pressure. Our results show that the aggregate bulk modulus (KS=125(2)GPa at 21°C) decreases monotonically with increasing temperature (∂KS//∂T=-1.8GPa/100K), in contrast to the results of Daneil et al. (1999) who observed a minimum in the bulk modulus at ~230°C. In general, the aggregate elastic wave velocities of lawsonite under high P-T conditions of a subducted slab are expected to remain comparable to those of anhydrous mafic silicates. This observation reinforces the notion that other hydrous minerals persist in subducted oceanic crust to considerable depth (~250km), in order to explain the low velocity layers observed in some subduction zones (e.g. Helffrich, 1996; Abers, 2000).

Affiliated with

Also associated with

No associations

Rating

Single-crystal elastic properties of lawsonite and their variation with temperature does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Single-crystal elastic properties of lawsonite and their variation with temperature, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Single-crystal elastic properties of lawsonite and their variation with temperature will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1325581