The compressibility of antigorite has been determined up to 8.826(8) GPa, for the first time by single crystal X-ray diffraction in a diamond anvil cell, on a specimen from Cerro del Almirez. Fifteen pressure–volume data, up to 5.910(6) GPa, have been fit by a thirdorder Birch–Murnaghan equation of state, yielding V0 = 2,914.07(23) A ° 3, KT0 = 62.9(4) GPa, with K0 = 6.1(2). The compression of antigorite is very anisotropic with axial compressibilities in the ratio 1.11:1.00:3.22 along a, b and c, respectively. The new equation of state leads to an estimation of the upper stability limit of antigorite that is intermediate with respect to existing values, and in better agreement with experiments. At pressures in excess of 6 GPa antigorite displays a significant volume softening that may be relevant for very cold subducting slabs
Nestola, F., Angel, R., Zhao, J., Garrido, C., Lopez Sanchez Vizcaino, V., Capitani, G., et al. (2009). Antigorite equation of state and anomalous softening at 6 GPa: an in-situ single-crystal X-ray diffraction study. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, 160(1), 33-43 [10.1007/s00410-009-0463-9].
Antigorite equation of state and anomalous softening at 6 GPa: an in-situ single-crystal X-ray diffraction study
CAPITANI, GIANCARLO;
2009
Abstract
The compressibility of antigorite has been determined up to 8.826(8) GPa, for the first time by single crystal X-ray diffraction in a diamond anvil cell, on a specimen from Cerro del Almirez. Fifteen pressure–volume data, up to 5.910(6) GPa, have been fit by a thirdorder Birch–Murnaghan equation of state, yielding V0 = 2,914.07(23) A ° 3, KT0 = 62.9(4) GPa, with K0 = 6.1(2). The compression of antigorite is very anisotropic with axial compressibilities in the ratio 1.11:1.00:3.22 along a, b and c, respectively. The new equation of state leads to an estimation of the upper stability limit of antigorite that is intermediate with respect to existing values, and in better agreement with experiments. At pressures in excess of 6 GPa antigorite displays a significant volume softening that may be relevant for very cold subducting slabs
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
