THE NATURE OF THE MOHOROVICIC DISCONTINUITY (Mo-ho chieh-mien ti hsing-chih),
Abstract
The paper discusses the various theories on the nature of the Mohorovicic discontinuity and the difficulties encountered by the phase-change hypothesis. By examining the velocity distribution data recently obtained by use of seismic body and surface waves, the following conclusions can be made: (1) The Mohorovicic discontinuity, either under the continents of the oceans, cannot be interpreted as a surface of phase transition. (2) The chemical composition of the upper mantle is not homogeneous in the vertical direction. The low-velocity layer in the upper mantle is probably caused by a change in composition rather than by the temperature effects. (3) The top surface of the asthenospheric low-velocity layer is deeper under the oceans than under the continents. (4) The chemical composition of the upper mantle, according to the data of radioactive measurements, may be some mixtures of eclogites or other ultra-basic rocks, their change of velocity due to temperature effects being very small. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1969
- Accession Number
- AD0692100
Entities
People
- Jung-sheng Tseng
Organizations
- Aeronautical Chart and Information Center