Elastic properties of anorthite and the nature of the lunar crust |
| |
| Authors: | Robert C Liebermann AE Ringwood |
| |
| Institution: | Research School of Earth Sciences, Australian National University, Canberra, A.C.T. Australia |
| |
| Abstract: | A polycrystalline specimen of anorthite has been hot-pressed atP = 15kbar andT = 1000°C in a piston-cylinder apparatus. Compressional(νp)and shear(νs) velocities are determined as a function of pressure to 7.5 kbar at room temperature by an ultrasonic pulse transmission technique. The specimen is less than 0.5% porous and is elastically isotropic within 1%. The velocities at 7.5 kbar areνp = 7.29km/secandνs = 3.85km/sec. These data are consistent with those for most terrestrial and lunar plagioclase rocks but not for certain anisotropic rocks and single crystals. The measured velocities demonstrate, moreover, that it is impossible to distinguish between rocks of gabbro, anorthositic gabbro, or anorthosite compositions for the 20–55 km layer of the lunar crust on the basis of seismic data alone. The mean composition of the crust could well be that of a gabbro (17% Al2O3) rather than of an anorthositic gabbro(～25%Al2O3) as assumed in some current models. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
