Publication Date:
2013-10-02
Description:
Tuite, -Ca 3 (PO 4 ) 2 , is regarded as an important phosphate mineral in the deep mantle playing a crucial role as a host for rare earth elements, large ion lithophile elements, and phosphorus. In this study we report the thermoelastic properties of synthetic -Ca 3 (PO 4 ) 2 at simultaneously high pressures and temperatures of up to 35.4 GPa and 1300 K, respectively, as determined by means of in situ energy-dispersive X-ray diffraction in a large-volume multi-anvil apparatus. The pressure-volume-temperature data obtained for -Ca 3 (PO 4 ) 2 were fitted by the high-temperature Birch-Murnaghan equation of state to yield V 0 = 447.4(4) Å 3 , K T0 = 100.8(18) GPa, K ' T0 = 5.74(13), ( K T / T ) P = –0.020(1) GPa/K, and α T = 3.26(18) x 10 –5 + 1.76(24) x 10 –8 T . In addition, fitting the present data to the Mie-Grüneisen-Debye equation of state gives 0 = 1.35(6), 0 = 944(136) K, and q = 0.37(29). Based on the thermoelastic properties obtained in our study, the density profiles of -Ca 3 (PO 4 ) 2 tuite along typical cold and hot slab geotherms were calculated and are compared with those of the coexisting silicate minerals in subducting mid-ocean ridge basalt.
Print ISSN:
0003-004X
Electronic ISSN:
1945-3027
Topics:
Geosciences
Permalink