Water-Related Diffusion and Deformation Effects in Quartz at Pressures of 1500 and 300 MPA
- Robert N. Schock
Published Online: 18 MAR 2013
Copyright 1985 by the American Geophysical Union.
Point Defects in Minerals
How to Cite
Mackwell, S. J. and Paterson, M. S. (1985) Water-Related Diffusion and Deformation Effects in Quartz at Pressures of 1500 and 300 MPA, in Point Defects in Minerals (ed R. N. Schock), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM031p0141
- Published Online: 18 MAR 2013
- Published Print: 1 JAN 1985
Print ISBN: 9780875900568
Online ISBN: 9781118664070
- Mineralogical chemistry—Congresses;
Natural and synthetic quartz specimens have been hydrothermally treated at 1500 MPa, 900°C and the diffusion profile of the water-related species determined by serial sectioning and infrared absorption measurements. The diffusion coefficient D is found to be around 10−12 to 10−11 m2s−1 and the solubility of the order of 1000 H/106Si at 1500 MPa, 900°C. The solubility therefore appears not to have increased greatly from 300 MPa to 1500 MPa whereas D has increased about six orders of magnitude, thereby explaining why quartz has been successfully weakened by diffusing water into it at 1500 MPa but not at 300 MPa. It has also been found that heat treatment of hydroxyl-rich synthetic quartz at 1500 MPa, 900°C, with and without added water, leads to a large increase in strength, suggesting that some sort of equilibration or re-arrangement of the hydroxyl has occurred and throwing into question the significance of the low flow stresses measured on synthetic quartz at low pressures.